For the past 20 years most of my research has been focused on investigating the potential health benefits of various dietary components or food patterns using randomized controlled trials. The interventions have involved vegetarian diets, soy, garlic, omega-3 fats/fish oil/flax oil, antioxidants, Ginkgo biloba, and popular weight loss diets. These trials have studied outcomes that include weight, blood lipids and lipoproteins, inflammatory markers, glucose, insulin, and body composition. Most of these trials have been NIH-funded. The most impactful of these is an NIH-funded weight loss diet study - DIETFITS (Diet Intervention Examining The Factors Interacting with Treatment Success) that involved randomizing 609 generally healthy, overweight/obese adults for one year to either Healthy Low-Fat or Healthy Low-Carb diet (JAMA, 2018).

In the past few years the interests of my research group have shifted to include three additional areas of inquiry. One of these is Stealth Nutrition. The central hypothesis driving this is that in order for more effective and impactful dietary improvements to be realized, health professionals need to consider adding non-health related approaches to their toolbox of strategies. Examples would be connections between food and 1) global warming and climate change, 2) animal rights and welfare, and 3) human labor abuses (e.g., slaughterhouses). An example is a summer Food and Farm Camp run in collaboration with the Santa Clara Unified School District since 2011. Every year ~125 kids 5-14 years of age come for a 1-week summer camp to tend, harvest, chop, cook, and eat vegetables...and play because it is summer camp! The objective is to study the factors influencing the behaviors and preferences that lead to maximizing vegetable consumption in kids.

A second area of interest and inquiry is institutional food. Universities, worksites, hospitals, and schools order and serve a lot of food, every day. If the choices offered are healthier, the consumption behaviors will be healthier. A key factor to success in institutional food is to make the food options "unapologetically delicious" a term I borrow from Greg Drescher, a colleague and friend at the Culinary Institute of America (the other CIA). Chefs in institutional food settings can be part of the solution to improving eating behaviors. In 2015 I helped to initiate a Stanford-CIA collaboration that now involves ~70 universities that have agreed to use their dining halls as living laboratories to study ways to maximize the synergy of taste, health and environmental sustainability. If universities, worksites, hospitals and schools change the foods they order and serve, that kind of institutional demand can change agricultural practices - a systems-level approach to achieving healthier dietary behaviors.

The third area is diet and the microbiome. Our lab has now partnered with the world renowned lab of Drs. Justin and Erica Sonnenburg at Stanford to conduct multiple human nutrition intervention studies. The most impactful of these studies was the Fe-Fi-Fo study (Fermented and Fiber-rich Foods) study published in Cell in 2021. In that 10-week intervention, study participants consuming more fermented foods increased their microbial diversity and decreased blood levels of ~20 inflammatory markers. Our ongoing Maternal and Offspring Microbiome Study (MOMS) is examining the transfer of the maternal microbiome to the infant among 132 pregnant women randomized to increase fiber, or fermented food, or both, or neither for their 2nd and 3rd trimester; the infants will be tracked for 18 months.

My long-term vision in this area is to help create a world-class Stanford Food Systems Initiative and build on the idea that Stanford is uniquely positioned geographically, culturally, and academically, to address national and global crises in the areas of obesity and diabetes that are directly related to our broken food systems.

Administrative Appointments

  • Leadership Committee, Lifestyle Council, American Heart Association (2019 - Present)
  • Sessions Planning Committee, American Heart Association (2018 - Present)
  • Director, Clinical and Translational Core, Stanford Diabetes Research Center (2017 - Present)
  • The Rehnborg Farquhar Professorship, Stanford University School of Medicine (2017 - Present)
  • Member, American Diabetes Association Dietary Guidelines Committee (2017 - 2019)
  • Scientific Advisory Committee, Culinary Institute of America (2012 - Present)
  • Director, Cardiovascular Epidemiology and Prevention Postdoctoral Training Fellowship, NIH/National Heart Lung and Blood Institute (2010 - Present)
  • Nutrition Committee, American Heart Association (2008 - 2012)

Honors & Awards

  • Outstanding Faculty Advisor, Program in Human Biology (2011-2012)
  • Teaching Award, Stanford Prevention Research Center (2011)
  • Teaching Award, Stanford Prevention Research Center (2005)
  • Distinguished Honorary Award, San Jose State University Department of Nutrition (2003)
  • Regents Fellowship, Univ. Cal. Berkeley (1988)

Boards, Advisory Committees, Professional Organizations

  • Scientific Advisory Board Member, Culinary Institute of America (2012 - Present)
  • Member, American Society of Nutrition (2011 - Present)
  • Member, Obesity Society (2008 - Present)
  • Member, American Heart Association: Nutrition Committee (2008 - 2012)
  • Member, American Heart Association Council on Nutrition, Physical Activity and Metabolism (2003 - Present)
  • Member, American Heart Association Council on Epidemiology and Prevention (1994 - Present)

Professional Education

  • PhD, Univ Cal Berkeley, Nutrition Science (1993)
  • B.A., Colgate University, Philosophy (1981)

Current Research and Scholarly Interests

For the past 20 years most of my research has been focused on investigating the potential health benefits of various dietary components or food patterns, which have been explored in the context of randomized controlled trials in free-living adult populations. Some of the interventions have involved vegetarian diets, soy foods and soy food components, garlic, omega-3 fats/fish oil/flax oil, antioxidants, Ginkgo biloba, and popular weight loss diets. These trials have ranged in duration from 8 weeks to a year, with study outcomes that have included weight, blood lipids and lipoproteins, inflammatory markers, glucose, insulin, blood pressure and body composition. Most of these trials have been NIH-funded. The most recent of these was an NIH funded weight loss diet study - DIETFITS (Diet Intervention Examining The Factors Interacting with Treatment Success) that involved randomizing 609 generally healthy, overweight/obese adults for one year to either a Healthy Low-Fat or a Healthy Low-Carb diet. The main findings were published in JAMA in 2018, and many secondary and exploratory analyses are in progress testing and generating follow-up hypotheses.

In the past few years the long-term interests of my research group have shifted to include two additional areas of inquiry. One of these is Stealth Nutrition. The central hypothesis driving this is that in order for more effective and impactful dietary improvements to be realized, public health professionals need to consider adding non-health related approaches to their strategies toolbox. Examples would be the connections between food and 1) global warming and climate change, 2) animal rights and welfare, and 3) human labor abuses (e.g., slaughterhouses, agriculture fields, fast food restaurants). An example of my ongoing research in this area is a summer Food and Farm Camp run in collaboration with the Santa Clara Unified School District since 2011. Every year ~125 kids between the ages of 5-14 years come for 1-week summer camp sessions led by Stanford undergraduates and an Education Director to tend, harvest, chop, cook, and eat vegetables...and play because it is summer camp! The objective is to study the factors influencing the behaviors and preferences that lead to maximizing vegetable consumption in kids.

A second area of interest and inquiry is institutional food. Universities, worksites, hospitals, and schools order and serve a lot of food, every day. If the choices offered are healthier, the consumption behaviors will be healthier. A key factor to success in institutional food is to make the food options to "unapologetically delicious" a term I borrow from Greg Drescher, a colleague and friend at the Culinary Institute of America (the other CIA). Chefs are trained to make great tasting food, and chefs in institutional food settings can be part of the solution to improving eating behaviors. In 2015 I helped to initiate a Stanford-CIA collaboration that now involves dozens of universities that have agreed to collectively use their dining halls as living laboratories to study ways to maximize the synergy of taste, health and environmental sustainability. If universities, worksites, hospitals and schools change the foods they serve, they will change the foods they order, and that kind of institutional demand can change agricultural practices - a systems-level approach to achieving healthier dietary behaviors.

My long-term vision in this area is to help create a world-class Stanford Food Systems Initiative and build on the idea that Stanford is uniquely positioned geographically, culturally, and academically, to address national and global crises in the areas of obesity and diabetes that are directly related to our broken food systems.

Clinical Trials

  • Adding Sleep Intervention to Traditional Diet and Exercise Approach to Weight Loss Not Recruiting

    The goal is to determine if improved sleep will increase/enhance weight loss among overweight adults with insomnia.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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  • Comparing Effects of 3 Sources of Garlic on Cholesterol Levels Not Recruiting

    The purpose of this study is to determine whether fresh garlic can positively affect cholesterol in adults with moderately high cholesterol levels. This study will also determine whether the same effects can be found for two main types of garlic supplements: a dried powdered garlic (designed to yield the same effect as fresh garlic) and an aged garlic extract preparation.

    Stanford is currently not accepting patients for this trial.

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  • Comparison of Popular Weight Loss Diets Not Recruiting

    This study will compare the safety and effectiveness of three popular weight loss plans. These plans will be compared with the USDA Dietary Guidelines.

    Stanford is currently not accepting patients for this trial.

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  • Contrasting Ketogenic and Mediterranean Diets in Individuals With Type 2 Diabetes and Prediabetes: The Keto-Med Trial Not Recruiting

    The objective of this study is to compare two metabolically distinct diets, WFKD vs Med-Plus, in order to examine the potential benefits, and unintended consequences, of going beyond a focus on maximally avoiding added sugars and refined grains, to also avoiding legumes, fruits, and whole grains.

    Stanford is currently not accepting patients for this trial. For more information, please contact Jennifer Robinson, PhD, 650-736-8577.

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  • Designing Food Voucher Programs to Reduce Disparities in Healthy Diets Not Recruiting

    Improving diets through increased food and vegetable (F\&V) consumption significantly reduces the risk of cardiovascular disease (CVD). Programs increasing the accessibility and affordability of F\&Vs among low-income Americans have been hindered by the food consumption cycle associated with poverty: the tendency to over-consume calories shortly after receiving funds at the beginning of each month, draining the budget for F\&V purchases, or for all food purchases, by month's end. An emerging theory about dietary behavior suggests that providing funds for food in smaller installments distributed throughout the month will smooth the consumption cycle and improve healthy eating-counteracting the tendency to respond to lump sum, once-monthly funding installments by purchasing calorie-dense foods immediately after funds are received. The theory also suggests that funds targeted toward specific healthy foods (e.g., F\&Vs) will improve diets more than untargeted funds, despite the inconvenience of utilizing targeted funds. We will rigorously test both hypotheses in a real-world setting by comparing alternative approaches for delivering food purchasing vouchers. We have established and tested the infrastructure to provide vouchers accepted by numerous food sellers (e.g., supermarkets, corner shops) in low-income neighborhoods. Leveraging this infrastructure, we will conduct a randomized trial with a two-by-two factorial design, comparing $20 of vouchers valid for one month to four $5 vouchers each valid for a sequential week of the month (lump sum versus distributed funding), and comparing vouchers restricted to F\&V purchases to vouchers redeemable for any food (targeted versus untargeted funding). Low-income adults (N=288) recruited through our community partners will be randomized to one of four 6-month interventions: monthly targeted, monthly untargeted, weekly targeted, or weekly untargeted vouchers. Participants will be assessed through efficient verbal 24-hour dietary recalls validated among low-literacy populations, to determine daily consumption of F\&Vs and metrics of overall dietary quality at months 0, 6 and 12 (6 months after vouchers end). Additional surveys will identify moderators and mediators of dietary improvement.

    Stanford is currently not accepting patients for this trial. For more information, please contact Sanjay Basu, (415) 881 - 7030.

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  • DIETFITS Study (Diet Intervention Examining the Factors Interacting With Treatment Success Not Recruiting

    Genomics research is advancing rapidly, and links between genes and obesity continue to be discovered and better defined. A growing number of single nucleotide polymorphisms (SNPs) in multiple genes have been shown to alter an individual's response to dietary macronutrient composition. Based on prior genetic studies evaluating the body's physiological responses to dietary carbohydrates or fats, the investigators identified multi-locus genotype patterns with SNPs from three genes (FABP2, PPARG, and ADRB2): a low carbohydrate-responsive genotype (LCG) and a low fat-responsive genotype (LFG). In a preliminary, retrospective study (using the A TO Z weight loss study data), the investigators observed a 3-fold difference in 12-month weight loss for initially overweight women who were determined to have been appropriately matched vs. mismatched to a low carbohydrate (Low Carb) or low fat (Low Fat) diet based on their multi-locus genotype pattern. The primary objective of this study is to confirm and expand on the preliminary results and determine if weight loss success can be increased if the dietary approach (Low Carb vs. Low Fat) is appropriately matched to an individual' s genetic predisposition (Low Carb Genotype vs. Low Fat Genotype) toward those diets.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, MS, RD, 650-736-8577.

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  • Effect of Fish Oil on Plasma Triglycerides in Adults Not Recruiting

    The purpose of this small, short pilot study is to determine the feasibility (e.g., recruitment, dose acceptance, retention) of a future longer trial comparing the effects of two types of omega-3 fats from fish oil on plasma triglycerides. The two types of fish oil are composed of (1) omega-3 fatty acids in triglyceride form; and (2) as esterified free fatty acids (i.e. ethyl esters). Although these two types of fish oil supplements are available to the public, it remains unclear whether they are equally effective in lowering plasma triglycerides.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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  • Effects of an Educational Planetary Plate Graphic on Meat Consumption Not Recruiting

    The objective of this research was to determine if adding a plate graphic depicting the components of the Eat Lancet Planetary Health diet (Figure 1) to food labels in Stanford University dining halls would lead to dining hall patrons making dietary decisions that better resemble the Planetary Health diet in comparison to a no signage control group. The study hypothesis was that presenting students with a plate graphic featuring the healthy reference diet would decrease objective measures of the amount of meat taken and therefore the environmental impact of student meals.

    Stanford is currently not accepting patients for this trial.

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  • Effects of Dietary Antioxidants on Cardiovascular Risk Factors Not Recruiting

    The aim of the Antioxidant Study was to compare the efficacy of foods naturally rich in antioxidants with that of antioxidants in a pill form on markers of inflammation and plasma cholesterol in healthy adults at risk of cardiovascular disease.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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  • Effects of Glutathione (an Antioxidant) and N-Acetylcysteine on Inflammation Not Recruiting

    The rationale for the potential role of antioxidants in the prevention of cardiovascular diseases (CVD) remains strong despite the disappointing results of recent trials with a few select antioxidant vitamins. Glutathione (GSH) is one of the body's most powerful antioxidant agents but there is a surprising paucity of data on its use as an interventional therapy. Glutathione, when taken orally, is immediately broken down into its constituent amino acids, of which cysteine is the only one to be essential. Available cysteine is the critical determinant of intracellular GSH concentrations. N-acetyl cysteine (NAC) is an antioxidant supplement that has been used to provide a source of cysteine to replete GSH levels. By replenishing endogenous glutathione, it is possible that NAC would exert the same effect(s) as exogenous GSH. However, there is a new delivery system, liposomal GSH, which keeps glutathione intact. In this study, the investigators propose to match the cysteine content of NAC and GSH and compare the effects of these two supplements, at two different doses, on markers of inflammation and oxidative stress.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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  • Effects of Omega-3 Fatty Acids on Markers of Inflammation Not Recruiting

    The major purpose of this study is to examine the effect of two sources of dietary omega-3 fatty acids, each given at two doses, on potential health benefits related to cardiovascular disease prevention. The two sources of dietary omega-3 fatty acids will be fish oil, and flaxseed oil.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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  • Effects of Raw Versus Other Milk Sources on Lactose Digestion Not Recruiting

    The purpose of this small, short pilot study is to determine the feasibility (e.g., recruitment, dose acceptance, retention) of a future longer trial comparing the effects of different types of milk (raw milk, cow's milk, nondairy-milk) on lactose maldigestion.

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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  • Effects of Soy Compounds on Breast Cancer, Prostate Cancer, and Bone Health Not Recruiting

    This study will determine the effects of soy products on in vitro surrogate cancer markers as well as bone density markers and quality of life parameters in men and women. This study will also determine concentrations of isoflavones (naturally occurring plant compounds that act like estrogen in the body) in prostate tissue that has been removed during prostatectomy, as well as in the blood.

    Stanford is currently not accepting patients for this trial.

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  • Study to Intervene With Nutrition for Gastroparesis Not Recruiting

    The study is a self-controlled study in which we will assess the nutritional effects of the Kate Farm Peptide 1.5 nutritional Formula in patients with gastroparesis, relative to their pre-enrollment nutritional diet regimen.

    Stanford is currently not accepting patients for this trial. For more information, please contact Brandon Lam, 650-725-0226.

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  • SWAP-MEAT: Study With Appetizing Plant Food - Meat Eating Alternatives Trial Not Recruiting

    This study aims to investigate the impact of replacing meat consumption with plant-based meat alternative consumption on cardiovascular health, the gut microbiome, and metabolic status.

    Stanford is currently not accepting patients for this trial. For more information, please contact Taylor Streaty, BS, 650-724-8310.

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  • The RAMP Study - Rejuvenation of the Aging Microbiota With Prebiotics Not Recruiting

    An individual's immune and metabolic status is coupled to consumed carbohydrates. Complex carbohydrates that are not digested by human enzymes may influence host biology by impacting microbiota composition and function, or act in a yet-unknown microbiota-independent manner. Prebiotics offer a promising safe route to influence host health, possibly via the microbiota. However, it remains largely unknown to what extent immune function and metabolism can be modulated by prebiotics.

    Stanford is currently not accepting patients for this trial. For more information, please contact Jennifer Robinson, PhD, 650-736-8577.

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  • Weight Loss Diet Study: Low Carb vs Low Fat Not Recruiting

    The traditional weight loss diet recommended by health professionals has been a low-fat, high-carbohydrate, calorie restricted diet. This recommendation has been challenged by a number of alternative dietary strategies, particularly low-carbohydrate diets. In several recent weight loss studies insulin resistant adults had more success with low- vs. high-carbohydrate diets, in contrast to insulin sensitive adults who had either more success or comparable success with the low-fat diets. The investigators enrolled 61 people with a wide range of insulin sensitivity/resistance. After determining their insulin resistance status, the investigators will split them in the middle and randomly assign them to one of four groups for six months: (1) Low-Carbohydrate/Insulin Resistant (LC/IR); (2) Low-Carbohydrate/Insulin Sensitive (LC/IS); (3) Low-Fat/Insulin Resistant (LF/IR); and (4) Low-Fat/Insulin Sensitive (LF/IS) (15 people/group). After 6 months the participants will switch diet for the following 6 months, i.e. those randomized to the Low-Carbohydrate diet will switch to the Low-Fat diet and vice-versa. The primary outcome of this study is to determine whether weight loss success can be increased if one follows the dietary approach appropriately matched to their insulin resistance status. Secondary outcomes include fasting insulin, glucose, lipids, and fatty acid composition. --------------------------------------------------------------------------------

    Stanford is currently not accepting patients for this trial. For more information, please contact Antonella Dewell, (650) 736 - 8577.

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2023-24 Courses

Stanford Advisees

All Publications

  • Switching diets after 6-months does not result in renewed weight loss: a secondary analysis of a 12-month crossover randomized trial. Scientific reports Landry, M. J., Ward, C. P., Cunanan, K. M., Fielding-Singh, P., Crimarco, A., Gardner, C. D. 2024; 14 (1): 9865


    Weight change trajectory from diet and lifestyle interventions typically involves rapid weight loss followed by a weight plateau after approximately 6 months. Changing from one weight-loss diet to another at the time of the plateau could instigate renewed weight loss. Therefore, our secondary analysis aimed to assess trajectory of weight loss in a 12-month, randomized, cross-over study. Forty-two adults were randomized to eat a healthy low-fat or healthy low-carbohydrate diet for 6 months then switched to the opposite diet for an additional 6 months. Regardless of diet assignment, participants experienced rapid initial weight loss, which slowed between 3 to 6 months. After switching diets at 6 months, weight modestly decreased until 9 months, but at a rate slower than the initial 3 months and slower than the rate from 3 to 6 months. This suggests that the weight loss plateau typically seen at 6 months is physiological and cannot be overcome by simply switching to a different weight-loss diet.

    View details for DOI 10.1038/s41598-024-60547-z

    View details for PubMedID 38684815

    View details for PubMedCentralID 5839290

  • Association of Dietary Adherence and Dietary Quality with Weight Loss Success among those Following Low-Carbohydrate and Low-Fat Diets: A Secondary Analysis of the DIETFITS Randomized Clinical Trial. The American journal of clinical nutrition Hauser, M. E., Hartle, J. C., Landry, M. J., Fielding-Singh, P., Shih, C. W., Qin, F., Rigdon, J., Gardner, C. D. 2023


    BACKGROUND: Eating a high-quality diet or adhering to a given dietary strategy may influence weight loss. However, these two factors have not been examined concurrently for those following macronutrient-limiting diets.OBJECTIVE: Determine whether improvement in dietary quality, change in dietary macronutrient composition, or the combination of these factors associated with differential weight loss when following a healthy low-carbohydrate (HLC) or healthy low-fat (HLF) diet.DESIGN: Generally healthy adults were randomized to HLC or HLF diets for 12-months (n=609) as part of a randomized controlled weight loss study. Participants with complete 24-hour dietary recall data at baseline and 12-months were included in this secondary analysis (total N=448; N=224 HLC, N=224 HLF). Participants were divided into four subgroups according to 12-month change in HEI-2010 score (above median = high-quality (HQ) and below median = low-quality (LQ)) and 12-month change in macronutrient intake (below median = high-adherence (HA) and above median = low-adherence (LA) for net carbohydrate (g) or fat (g) for HLC and HLF, respectively). Baseline to 12-month changes in mean BMI were compared for those in HQ/HA, HQ/LA, LQ/HA subgroups versus the LQ/LA subgroup within HLC and HLF.RESULTS: For HLC, changes (95 % CI) in mean BMI were -1.15 kg/m2 (-2.04, -0.26) for HQ/HA, -0.30 (-1.22, 0.61) for HQ/LA, and -0.80 (-1.74, 0.14) for LQ/HA compared with the LQ/LA subgroup. For HLF, changes (95% CI) in mean BMI were -1.11kg/m2 (-2.10, -0.11) for HQ/HA, -0.26 (-1.26, 0.75) for HQ/LA, and -0.66 (-1.74, 0.41) for LQ/HA compared with the LQ/LA subgroup.CONCLUSION: Within both HLC and HLF diet arms, 12-month decrease in BMI was significantly greater in HQ/HA subgroups relative to LQ/LA subgroups. Neither HQ nor HA alone were significantly different than LQ/LA subgroups. Results of this analysis support the combination of dietary adherence and high-quality diets for weight loss.CLINICAL TRIAL REGISTRY: (Identifier: NCT01826591).

    View details for DOI 10.1016/j.ajcnut.2023.10.028

    View details for PubMedID 37931749

  • Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical Twins: A Randomized Clinical Trial. JAMA network open Landry, M. J., Ward, C. P., Cunanan, K. M., Durand, L. R., Perelman, D., Robinson, J. L., Hennings, T., Koh, L., Dant, C., Zeitlin, A., Ebel, E. R., Sonnenburg, E. D., Sonnenburg, J. L., Gardner, C. D. 2023; 6 (11): e2344457


    Increasing evidence suggests that, compared with an omnivorous diet, a vegan diet confers potential cardiovascular benefits from improved diet quality (ie, higher consumption of vegetables, legumes, fruits, whole grains, nuts, and seeds).To compare the effects of a healthy vegan vs healthy omnivorous diet on cardiometabolic measures during an 8-week intervention.This single-center, population-based randomized clinical trial of 22 pairs of twins (N = 44) randomized participants to a vegan or omnivorous diet (1 twin per diet). Participant enrollment began March 28, 2022, and continued through May 5, 2022. The date of final follow-up data collection was July 20, 2022. This 8-week, open-label, parallel, dietary randomized clinical trial compared the health impact of a vegan diet vs an omnivorous diet in identical twins. Primary analysis included all available data.Twin pairs were randomized to follow a healthy vegan diet or a healthy omnivorous diet for 8 weeks. Diet-specific meals were provided via a meal delivery service from baseline through week 4, and from weeks 5 to 8 participants prepared their own diet-appropriate meals and snacks.The primary outcome was difference in low-density lipoprotein cholesterol concentration from baseline to end point (week 8). Secondary outcome measures were changes in cardiometabolic factors (plasma lipids, glucose, and insulin levels and serum trimethylamine N-oxide level), plasma vitamin B12 level, and body weight. Exploratory measures were adherence to study diets, ease or difficulty in following the diets, participant energy levels, and sense of well-being.A total of 22 pairs (N = 44) of twins (34 [77.3%] female; mean [SD] age, 39.6 [12.7] years; mean [SD] body mass index, 25.9 [4.7]) were enrolled in the study. After 8 weeks, compared with twins randomized to an omnivorous diet, the twins randomized to the vegan diet experienced significant mean (SD) decreases in low-density lipoprotein cholesterol concentration (-13.9 [5.8] mg/dL; 95% CI, -25.3 to -2.4 mg/dL), fasting insulin level (-2.9 [1.3] μIU/mL; 95% CI, -5.3 to -0.4 μIU/mL), and body weight (-1.9 [0.7] kg; 95% CI, -3.3 to -0.6 kg).In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their Identifier: NCT05297825.

    View details for DOI 10.1001/jamanetworkopen.2023.44457

    View details for PubMedID 38032644

  • Popular Dietary Patterns: Alignment With American Heart Association 2021 Dietary Guidance: A Scientific Statement From the American Heart Association CIRCULATION Gardner, C. K., Vadiveloo, M. S., Petersen, K., Anderson, C. M., Springfield, S., Van Horn, L., Khera, A., Lamendola, C., Mayo, S. M., Joseph, J. J., Amer Heart Assoc Council Lifestyle, Council Cardiovasc Stroke Nursing, Council Hypertension, Council Peripheral Vasc Dis 2023; 147 (22): 1715-1730


    The evolution of dietary guidelines from isolated nutrients to broader dietary pattern recommendations results from growing knowledge of the synergy between nutrients and their food sources as they influence health. Macronutrient and micronutrient needs can be met by consuming various dietary patterns, but guidance is often required to facilitate population-wide adherence to wise food choices to achieve a healthy dietary pattern. This is particularly true in this era with the proliferation of nutrition misinformation and misplaced emphasis. In 2021, the American Heart Association issued a scientific statement outlining key principles of a heart-healthy dietary pattern that could be operationalized in various ways. The objective of this scientific statement is to assess alignment of commonly practiced US dietary patterns with the recently published American Heart Association criteria, to determine clinical and cultural factors that affect long-term adherence, and to propose approaches for adoption of healthy dietary patterns. This scientific statement is intended to serve as a tool for clinicians and consumers to evaluate whether these popular dietary pattern(s) promote cardiometabolic health and suggests factors to consider when adopting any pattern to improve alignment with the 2021 American Heart Association Dietary Guidance. Numerous patterns strongly aligned with 2021 American Heart Association Dietary Guidance (ie, Mediterranean, DASH [Dietary Approaches to Stop Hypertension], pescetarian, vegetarian) can be adapted to reflect personal and cultural preferences and budgetary constraints. Thus, optimal cardiovascular health would be best supported by developing a food environment that supports adherence to these patterns wherever food is prepared or consumed.

    View details for DOI 10.1161/CIR.0000000000001146

    View details for Web of Science ID 001004227800008

    View details for PubMedID 37128940

  • Effect of a Ketogenic Diet versus Mediterranean Diet on HbA1c in Individuals with Prediabetes and Type 2 Diabetes Mellitus: the Interventional Keto-Med Randomized Crossover Trial. The American journal of clinical nutrition Gardner, C. D., Landry, M. J., Perelman, D., Petlura, C., Durand, L. R., Aronica, L., Crimarco, A., Cunanan, K. M., Chang, A., Dant, C. C., Robinson, J. L., Kim, S. H. 2022


    Consensus has not been reached on what constitutes an optimal diet in individuals with prediabetes and type 2 diabetes (T2DM), especially between low-carbohydrate options.To compare two low-carbohydrate diets with 3 key similarities (incorporate non-starchy vegetables and avoid added sugars and refined grains) and 3 key differences (incorporate vs avoid legumes, fruits, and whole intact grains), for their effects on glucose control and cardiometabolic risk factors in individuals with prediabetes and T2DM.Keto-Med was a randomized, crossover, interventional trial. Forty participants aged ≥ 18 years with prediabetes or T2DM followed a Well Formulated Ketogenic Diet (WFKD) and Mediterranean-Plus diet (Med-Plus) for 12-weeks each, in random order. Diets shared 3 key similarities noted above. Med-Plus incorporated legumes, fruits, and whole intact grains while WFKD avoided them. Primary outcome was % change in HbA1c after 12-weeks on each diet. Secondary and exploratory outcomes included % change in body weight, fasting insulin, glucose, and blood lipids, glucose (continuous glucose monitor), and nutrient intake.Primary analysis had n = 33 with complete data. HbA1c did not differ between diets at 12-weeks. Triglycerides decreased more for WFKD (% change(SEM)): -16%(4%) vs -5%(6%), p = 0.02) and LDL-C was higher for WFKD (+10%(4%) vs -5%(5%), p = 0.01). Weight decreased 8%(1%) vs 7%(1%) and HDL-C increased 11%(2%) vs 7%(3%) for WFKD vs Med-Plus, respectively; however, there was a significant interaction of diet by order for both. Participants had lower intakes of fiber and 3 nutrients on WFKD vs Med-Plus. Twelve-week follow-up data suggested Med-Plus diet was more sustainable.HbA1c was not different between diet phases after 12-weeks, but improved from baseline on both diets, likely due to several shared dietary aspects. WFKD was beneficial for greater decrease in triglycerides, but also had potential untoward risks from elevated LDL-C, and lower nutrient intakes from avoiding legumes, fruits, and whole intact grains, as well as being less NCT03810378.

    View details for DOI 10.1093/ajcn/nqac154

    View details for PubMedID 35641199

  • Sustainable Diets for Cardiovascular Disease Prevention and Management. Current atherosclerosis reports Mendoza-Vasconez, A. S., Landry, M. J., Crimarco, A., Bladier, C., Gardner, C. D. 2021; 23 (7): 31


    PURPOSE OF REVIEW: Healthy dietary patterns are recommended for prevention of cardiovascular disease, which remains the leading cause of morbidity and mortality globally. In this review, we discuss dietary patterns that are not only optimal for CVD prevention and management but also sustainable in maximizing health, environmental, and economic benefits.RECENT FINDINGS: The growing literature on sustainable diets in the context of environmental sustainability includes subtopics of climate change, land use, biodiversity loss, freshwater use, and reactive nitrogen emissions. Similarly, economic sustainability, beyond the retail cost of food, extends to healthcare costs and the economic costs of environmental destruction related to current agricultural practices and food choices. Dietary patterns that are high in plant foods and low in animal foods could maximize health, environmental, and economic benefits; however, questions remain about how to best promote these patterns to achieve wider adoption in an environmentally and economically sustainable way.

    View details for DOI 10.1007/s11883-021-00929-0

    View details for PubMedID 33970349

  • Gut-microbiota-targeted diets modulate human immune status. Cell Wastyk, H. C., Fragiadakis, G. K., Perelman, D., Dahan, D., Merrill, B. D., Yu, F. B., Topf, M., Gonzalez, C. G., Van Treuren, W., Han, S., Robinson, J. L., Elias, J. E., Sonnenburg, E. D., Gardner, C. D., Sonnenburg, J. L. 2021


    Diet modulates the gut microbiome, which in turn can impact the immune system. Here, we determined how two microbiota-targeted dietary interventions, plant-based fiber and fermented foods, influence the human microbiome and immune system in healthy adults. Using a 17-week randomized, prospective study (n = 18/arm) combined with -omics measurements of microbiome and host, including extensive immune profiling, we found diet-specific effects. The high-fiber diet increased microbiome-encoded glycan-degrading carbohydrate active enzymes (CAZymes) despite stable microbial community diversity. Although cytokine response score (primary outcome) was unchanged, three distinct immunological trajectories in high-fiber consumers corresponded to baseline microbiota diversity. Alternatively, the high-fermented-food diet steadily increased microbiota diversity and decreased inflammatory markers. The data highlight how coupling dietary interventions to deep and longitudinal immune and microbiome profiling can provide individualized and population-wide insight. Fermented foods may be valuable in countering the decreased microbiome diversity and increased inflammation pervasive in industrialized society.

    View details for DOI 10.1016/j.cell.2021.06.019

    View details for PubMedID 34256014

  • Impact of Child Interaction With Food Preparation on Vegetable Preferences: A Farm-Based Education Approach. Journal of nutrition education and behavior Crary, I. L., Ardoin, N. M., Gardner, C. 2021


    To identify the impact of child involvement in vegetable preparation on vegetable preference and attitudes toward eating vegetables.Pre-post mixed-methods.Food and Farming Camp at a nonprofit urban farm in Sunnyvale, California.Camp participants aged 8-10 years (n = 34 girls, n = 12 boys), and aged 11-14 years (n = 19 girls, n = 4 boys).Involvement in vegetable preparation through harvesting, cutting, cooking, and seasoning before consumption. Interviews identified camper perception of vegetable preference and involvement in preparation.Change in vegetable preference from baseline with and without involvement in vegetable preparation. Attitudes toward involvement in vegetable preparation.Adjustment of preferences to baseline followed by tests of hypotheses to identify differences with involvement. Thematic, qualitative coding to identify prevalent themes within interview responses.Younger campers preferred vegetables they prepared (P < 0.05), except for carrots. Campers were more likely to choose vegetables they prepared (P < 0.05). Campers of both age groups were curious to try their vegetable creations and described feelings of pride and responsibility related to preparing vegetables.Involvement with food preparation, in particular in a garden-based setting, may provide an accessible method to improve child vegetable preference.

    View details for DOI 10.1016/j.jneb.2021.08.009

    View details for PubMedID 34776345

  • Nutrition Study Design Issues-Important Issues for Interpretation AMERICAN JOURNAL OF HEALTH PROMOTION Gardner, C. D., Crimarco, A., Landry, M. J., Fielding-Singh, P. 2020; 34 (8): 951–54
  • A randomized crossover trial on the effect of plant-based compared with animal-based meat on trimethylamine-N-oxide and cardiovascular disease risk factors in generally healthy adults: Study With Appetizing Plantfood-Meat Eating Alternative Trial (SWAP-MEAT). The American journal of clinical nutrition Crimarco, A. n., Springfield, S. n., Petlura, C. n., Streaty, T. n., Cunanan, K. n., Lee, J. n., Fielding-Singh, P. n., Carter, M. M., Topf, M. A., Wastyk, H. C., Sonnenburg, E. D., Sonnenburg, J. L., Gardner, C. D. 2020


    Despite the rising popularity of plant-based alternative meats, there is limited evidence of the health effects of these products.We aimed to compare the effect of consuming plant-based alternative meat (Plant) as opposed to animal meat (Animal) on health factors. The primary outcome was fasting serum trimethylamine-N-oxide (TMAO). Secondary outcomes included fasting insulin-like growth factor 1, lipids, glucose, insulin, blood pressure, and weight.SWAP-MEAT (The Study With Appetizing Plantfood-Meat Eating Alternatives Trial) was a single-site, randomized crossover trial with no washout period. Participants received Plant and Animal products, dietary counseling, lab assessments, microbiome assessments (16S), and anthropometric measurements. Participants were instructed to consume ≥2 servings/d of Plant compared with Animal for 8 wk each, while keeping all other foods and beverages as similar as possible between the 2 phases.The 36 participants who provided complete data for both crossover phases included 67% women, were 69% Caucasian, had a mean ± SD age 50 ± 14 y, and BMI 28 ± 5 kg/m2. Mean ± SD servings per day were not different by intervention sequence: 2.5 ± 0.6 compared with 2.6 ± 0.7 for Plant and Animal, respectively (P = 0.76). Mean ± SEM TMAO concentrations were significantly lower overall for Plant (2.7 ± 0.3) than for Animal (4.7 ± 0.9) (P = 0.012), but a significant order effect was observed (P = 0.023). TMAO concentrations were significantly lower for Plant among the n = 18 who received Plant second (2.9 ± 0.4 compared with 6.4 ± 1.5, Plant compared with Animal, P = 0.007), but not for the n = 18 who received Plant first (2.5 ± 0.4 compared with 3.0 ± 0.6, Plant compared with Animal, P = 0.23). Exploratory analyses of the microbiome failed to reveal possible responder compared with nonresponder factors. Mean ± SEM LDL-cholesterol concentrations (109.9 ± 4.5 compared with 120.7 ± 4.5 mg/dL, P = 0.002) and weight (78.7 ± 3.0 compared with 79.6 ± 3.0 kg, P < 0.001) were lower during the Plant phase.Among generally healthy adults, contrasting Plant with Animal intake, while keeping all other dietary components similar, the Plant products improved several cardiovascular disease risk factors, including TMAO; there were no adverse effects on risk factors from the Plant products.This trial was registered at as NCT03718988.

    View details for DOI 10.1093/ajcn/nqaa203

    View details for PubMedID 32780794

  • Increasing Vegetable Intake by Emphasizing Tasty and Enjoyable Attributes: A Randomized Controlled Multisite Intervention for Taste-Focused Labeling. Psychological science Turnwald, B. P., Bertoldo, J. D., Perry, M. A., Policastro, P., Timmons, M., Bosso, C., Connors, P., Valgenti, R. T., Pine, L., Challamel, G., Gardner, C. D., Crum, A. J. 2019: 956797619872191


    Healthy food labels tout health benefits, yet most people prioritize tastiness in the moment of food choice. In a preregistered intervention, we tested whether taste-focused labels compared with health-focused labels increased vegetable intake at five university dining halls throughout the United States. Across 137,842 diner decisions, 185 days, and 24 vegetable types, taste-focused labels increased vegetable selection by 29% compared with health-focused labels and by 14% compared with basic labels. Vegetable consumption also increased. Supplementary studies further probed the mediators, moderators, and boundaries of these effects. Increased expectations of a positive taste experience mediated the effect of taste-focused labels on vegetable selection. Moderation tests revealed greater effects in settings that served tastier vegetable recipes. Taste-focused labels outperformed labels that merely contained positive words, fancy words, or lists of ingredients. Together, these studies show that emphasizing tasty and enjoyable attributes increases vegetable intake in real-world settings in which vegetables compete with less healthy options.

    View details for DOI 10.1177/0956797619872191

    View details for PubMedID 31577177

  • Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report DIABETES CARE Evert, A. B., Dennison, M., Gardner, C. D., Garvey, W., Lau, K., MacLeod, J., Mitri, J., Pereira, R. F., Rawlings, K., Robinson, S., Saslow, L., Uelmen, S., Urbanski, P. B., Yancy, W. S. 2019; 42 (5): 731–54

    View details for DOI 10.2337/dci19-0014

    View details for Web of Science ID 000465238900015

  • Maximizing the intersection of human health and the health of the environment with regard to the amount and type of protein produced and consumed in the United States NUTRITION REVIEWS Gardner, C. D., Hartle, J. C., Garrett, R. D., Offringa, L. C., Wasserman, A. S. 2019; 77 (4): 197–215
  • Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion The DIETFITS Randomized Clinical Trial JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Gardner, C. D., Trepanowski, J. F., Del Gobbo, L. C., Hauser, M. E., Rigdon, J., Ioannidis, J. A., Desai, M., King, A. C. 2018; 319 (7): 667–79


    Dietary modification remains key to successful weight loss. Yet, no one dietary strategy is consistently superior to others for the general population. Previous research suggests genotype or insulin-glucose dynamics may modify the effects of diets.To determine the effect of a healthy low-fat (HLF) diet vs a healthy low-carbohydrate (HLC) diet on weight change and if genotype pattern or insulin secretion are related to the dietary effects on weight loss.The Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) randomized clinical trial included 609 adults aged 18 to 50 years without diabetes with a body mass index between 28 and 40. The trial enrollment was from January 29, 2013, through April 14, 2015; the date of final follow-up was May 16, 2016. Participants were randomized to the 12-month HLF or HLC diet. The study also tested whether 3 single-nucleotide polymorphism multilocus genotype responsiveness patterns or insulin secretion (INS-30; blood concentration of insulin 30 minutes after a glucose challenge) were associated with weight loss.Health educators delivered the behavior modification intervention to HLF (n = 305) and HLC (n = 304) participants via 22 diet-specific small group sessions administered over 12 months. The sessions focused on ways to achieve the lowest fat or carbohydrate intake that could be maintained long-term and emphasized diet quality.Primary outcome was 12-month weight change and determination of whether there were significant interactions among diet type and genotype pattern, diet and insulin secretion, and diet and weight loss.Among 609 participants randomized (mean age, 40 [SD, 7] years; 57% women; mean body mass index, 33 [SD, 3]; 244 [40%] had a low-fat genotype; 180 [30%] had a low-carbohydrate genotype; mean baseline INS-30, 93 μIU/mL), 481 (79%) completed the trial. In the HLF vs HLC diets, respectively, the mean 12-month macronutrient distributions were 48% vs 30% for carbohydrates, 29% vs 45% for fat, and 21% vs 23% for protein. Weight change at 12 months was -5.3 kg for the HLF diet vs -6.0 kg for the HLC diet (mean between-group difference, 0.7 kg [95% CI, -0.2 to 1.6 kg]). There was no significant diet-genotype pattern interaction (P = .20) or diet-insulin secretion (INS-30) interaction (P = .47) with 12-month weight loss. There were 18 adverse events or serious adverse events that were evenly distributed across the 2 diet groups.In this 12-month weight loss diet study, there was no significant difference in weight change between a healthy low-fat diet vs a healthy low-carbohydrate diet, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss. In the context of these 2 common weight loss diet approaches, neither of the 2 hypothesized predisposing factors was helpful in identifying which diet was better for Identifier: NCT01826591.

    View details for PubMedID 29466592

  • Regarding: the impacts of partial replacement of red and processed meat with legumes or cereals on protein and amino acid intakes: a modelling study in the Finnish adult population. Annals of medicine Mariotti, F., Gardner, C., Fouillet, H., Huneau, J. F. 2024; 56 (1): 2341757

    View details for DOI 10.1080/07853890.2024.2341757

    View details for PubMedID 38738422

  • Collegiate student-athletes use and knowledge of third-party tested nutritional supplements: An exploratory study. Journal of athletic training Schott, K. D., Seltzer, R. G., Zorn, S. P., Frakes, M., Price, M., Valient, M. W., Ritz, P., Gardner, C., Wardenaar, F. C. 2024


    Nutritional supplement use in athletes is common, accompanied by potential doping risk.Determine athletes' nutritional supplement and third-party tested (TPT) supplement use, supplement knowledge as well as factors influencing their behavior.Cross-Sectional Study.NCAA DI athletic departments.Student-athletes (n=410, 53% female, age 21.4±1.6 years).Survey questions addressed topics including nutritional supplement knowledge and use, TPT supplement knowledge, use and logo recognition and data were 11 stratified for sex differences.Athletes (91%) report the use of supplements, but the total number of supplements used (median and interquartile range, IQR) is lower in females (7, 4-11), than males (9, 4-12), with U=17960, p=0.01. A total of 48% (n=191, out of 402 responses) reported purchasing supplements outside of their athletic department, with significantly fewer females (40%, n=84) than males (56%, n=107) reporting this behavior (χ2=11.20, p<0.001). No association between TPT logo recognition and TPT use was seen (χ2=0.238, p=0.63). Of all athletes using supplements, 38% (n=140) reported "consistent TPT use", while females (36%, n=70) reported this less often than males (41%, n=70, χ2=0.952, p<0.32). No sex differences were seen for receiving nutritional counseling (89%, p=0.37), or the low nutritional supplement knowledge (<50%, p=0.38), however, males had 2.5 times greater odds at recognizing a TPT organization logo than females (OR=2.45, with 95% CI=1.58-3.79).Most athletes use nutritional supplements. Females report slightly fewer supplements than males, while also less frequently purchasing them outside their athletic department, potentially explaining the lower TPT logo recognition in female athletes.

    View details for DOI 10.4085/1062-6050-0098.24

    View details for PubMedID 38894679

  • The knowledge, attitudes, and perceptions towards a plant-based dietary pattern: a survey of obstetrician-gynecologists. Frontiers in nutrition Landry, M. J., Ward, C. P., Koh, L. M., Gardner, C. D. 2024; 11: 1381132


    Obstetricians-gynecologists (OB/GYNs) play a critical role for their pregnant patients during their perinatal period, but research on OB/GYNs knowledge, attitudes, and perceptions regarding plant-based dietary patterns (PBDP) and how this may influence recommendations to patients is lacking. An online cross-sectional survey was conducted to examine OB/GYN's knowledge, attitudes, and perceptions towards a PBDP.Postcards were mailed in June 2023 to a convenience sample of 5,000 OB/GYNs across the US using a mailing list provided by the American College of Obstetricians and Gynecologists. Postcards had a brief study description and a QR code that linked to an online survey asking questions about demographics, behavior (e.g., nutritional habits), and other factors that may influence knowledge, attitudes, and perceptions towards a PBDP for their patients.Ninety-six OB/GYNs completed the full questionnaire (~2% response rate). Most (92%) felt that it is within an OB/GYN's role to incorporate nutrition education and counseling within practice. However, 72% felt inadequately trained to discuss nutrition and diet-related issues with patients. Despite a perceived lack of nutrition training, 86% reported that a PBDP was safe and health-promoting, and 81% reported that a well-planned PBDP could adequately meet all nutritional needs of pregnant and lactating patients.Findings suggest that OB/GYNs are generally knowledgeable about the components and health benefits of a plant-based diets. However, nutrient adequacy misconceptions and lack of sufficient training to discuss nutrition with patients may result in OB/GYNs not recommending PBDPs to patients. These findings underscore the need to enhance OB/GYN graduate medical education and training by integrating education on PBDPs, therefore improving a clinician's ability to confidently and effectively counsel pregnant persons on this aspect of perinatal care.

    View details for DOI 10.3389/fnut.2024.1381132

    View details for PubMedID 38895659

    View details for PubMedCentralID PMC11183291

  • Diet Quality and Resilience through Adulthood: A Cross-Sectional Analysis of the WELL for Life Study. Nutrients Springfield-Trice, S., Joyce, C., Wu, Y. H., Hsing, A. W., Cunanan, K., Gardner, C. 2024; 16 (11)


    Despite evidence suggesting the importance of psychological resilience for successful aging, little is known about the relationship between diet quality and resilience at different ages. Our study aims to examine the association between diet quality and resilience across the stages of adulthood. Using Stanfords' WELL for Life (WELL) survey data, we conducted a cross-sectional study of diet quality, resilience, sociodemographic, perceived stress, lifestyle, and mental health factors among 6171 Bay Area adults. Diet quality was measured by the WELL Diet Score, which ranges from 0-120. A higher score indicates a better diet quality. Linear regression analysis was used to evaluate the association between the WELL Diet Score and overall resilience and within the following age groups: early young (18-24), late young (25-34), middle (35-49), and late adulthood (≥50). To test whether these associations varied by age groups, an age group by resilience interaction term was also examined. In the fully adjusted model, the WELL Diet Score was positively and significantly associated with overall resilience (all ages (β = 1.2 ± sd: 0.2, p < 0.001)) and within each age group (early young (β = 1.1 ± sd: 0.3, p < 0.001); late young (β = 1.2 ± sd: 0.3, p < 0.001); middle (β = 0.9 ± sd: 0.3, p < 0.001); and late adulthood (β = 1.0 ± sd: 0.3, p < 0.001)). Young adults demonstrated the strongest associations between diet quality and resilience. However, there were no significant age-by-resilience interactions. Diet quality may be positively associated with resilience at all stages of adulthood. Further research is needed to determine whether assessing and addressing resilience could inform the development of more effective dietary interventions, particularly in young adults.

    View details for DOI 10.3390/nu16111724

    View details for PubMedID 38892657

    View details for PubMedCentralID PMC11174593

  • Vida Sana y Completa: A randomized controlled trial to examine the effectiveness of diabetes prevention with and without medically supportive groceries among Latina women. Contemporary clinical trials Rosas, L. G., Perez, J. A., Chen, W. T., Xiao, L., Espinosa, P. R., Venditti, E. M., Lewis, M. A., Gardner, C. D., Marti, A., Martinez, E., Murthy, M., Hauser, M. 2024: 107582


    Latina women have a high prevalence of obesity and obesity-related chronic diseases, such as diabetes. Approximately half of Latinas with obesity will also experience food insecurity, or a lack of access to enough food for an active and healthy life. Food insecurity is a barrier for effective prevention and management of obesity-related chronic diseases. The goal of this type 1 hybrid comparative effectiveness trial is to compare a culturally-tailored diabetes prevention intervention with and without medically supportive groceries. Adult Latina women (n = 412) with obesity (Body Mass Index (BMI) of >30 kg/m2) and food insecurity will be 1:1 randomized to the Vida Sana intervention (control), or to Vida Sana y Completa (intervention plus integrated treatment for food insecurity). Vida Sana is an evidence-based culturally tailored, 12-month diabetes prevention intervention that targets at least 5% weight loss and at least 150 min/week of moderate-to-vigorous physical activity. Participants enrolled in Vida Sana y Completa will also receive 12 weekly deliveries of medically supportive groceries. Those in Vida Sana alone will receive information on local food resources. Participants will be assessed at baseline and every 6 months for 24 months. The primary outcome is weight loss at 12 months. Secondary outcomes include weight loss maintenance, diet quality, and quality of life. Barriers and facilitators of implementation will be assessed using mixed methods according to the Consolidated Framework for Implementation Research. This study will provide critical evidence for addressing the combination of obesity and food insecurity in primary care for diabetes prevention. Trial Registration: NCT052111.

    View details for DOI 10.1016/j.cct.2024.107582

    View details for PubMedID 38810932

  • Cardiovascular health and cancer risk associated with plant based diets: An umbrella review. PloS one Capodici, A., Mocciaro, G., Gori, D., Landry, M. J., Masini, A., Sanmarchi, F., Fiore, M., Coa, A. A., Castagna, G., Gardner, C. D., Guaraldi, F. 2024; 19 (5): e0300711


    Cardiovascular diseases (CVDs) and cancer are the two main leading causes of death and disability worldwide. Suboptimal diet, poor in vegetables, fruits, legumes and whole grain, and rich in processed and red meat, refined grains, and added sugars, is a primary modifiable risk factor. Based on health, economic and ethical concerns, plant-based diets have progressively widespread worldwide.This umbrella review aims at assessing the impact of animal-free and animal-products-free diets (A/APFDs) on the risk factors associated with the development of cardiometabolic diseases, cancer and their related mortalities.PubMed and Scopus were searched for reviews, systematic reviews, and meta-analyses published from 1st January 2000 to 31st June 2023, written in English and involving human subjects of all ages. Primary studies and reviews/meta-analyses based on interventional trials which used A/APFDs as a therapy for people with metabolic diseases were excluded.The umbrella review approach was applied for data extraction and analysis. The revised AMSTAR-R 11-item tool was applied to assess the quality of reviews/meta-analyses.Overall, vegetarian and vegan diets are significantly associated with better lipid profile, glycemic control, body weight/BMI, inflammation, and lower risk of ischemic heart disease and cancer. Vegetarian diet is also associated with lower mortality from CVDs. On the other hand, no difference in the risk of developing gestational diabetes and hypertension were reported in pregnant women following vegetarian diets. Study quality was average. A key limitation is represented by the high heterogeneity of the study population in terms of sample size, demography, geographical origin, dietary patterns, and other lifestyle confounders.Plant-based diets appear beneficial in reducing cardiometabolic risk factors, as well as CVDs, cancer risk and mortality. However, caution should be paid before broadly suggesting the adoption of A/AFPDs since the strength-of-evidence of study results is significantly limited by the large study heterogeneity alongside the potential risks associated with potentially restrictive regimens.

    View details for DOI 10.1371/journal.pone.0300711

    View details for PubMedID 38748667

    View details for PubMedCentralID PMC11095673

  • Development of a screener to assess athlete risk behavior of not using third-party tested nutritional supplements. Frontiers in nutrition Wardenaar, F. C., Schott, K. D., Seltzer, R. G., Gardner, C. D. 2024; 11: 1381731


    The aim of this cross-sectional study was to develop an algorithm to predict athletes use of third-party tested (TPT) supplements. Therefore, a nutritional supplement questionnaire was used with a section about self-reported TPT supplement use.Outcomes were randomly assigned to a training dataset to identify predictors using logistic regression models, or a cross-validation dataset. Training data were used to develop an algorithm with a score from 0 to 100 predicting use or non-use of TPT nutritional supplements.A total of n = 410 NCAA Division I student-athletes (age: 21.4 ± 1.6 years, 53% female, from >20 sports) were included. Then n = 320 were randomly selected, of which 34% (n = 109) of users consistently reported that all supplements they used were TPT. Analyses resulted in a 10-item algorithm associated with use or non-use of TPT. Risk quadrants provided the best fit for classifying low vs. high risk toward inconsistent TPT-use resulting in a cut-off ≥60% (χ2(4) = 61.26, P < 0.001), with reasonable AUC 0.78. There was a significant association for TPT use (yes/no) and risk behavior (low vs. high) defined from the algorithm (χ2(1)=58.6, P < 0.001). The algorithm had a high sensitivity, classifying 89% of non-TPT users correctly, while having a low specificity, classifying 49% of TPT-users correctly. This was confirmed by cross-validation (n = 34), reporting a high sensitivity (83%), despite a lower AUC (0.61).The algorithm classifies high-risk inconsistent TPT-users with reasonable accuracy, but lacks the specificity to classify consistent users at low risk. This approach should be useful in identifying athletes that would benefit from additional counseling.

    View details for DOI 10.3389/fnut.2024.1381731

    View details for PubMedID 38812931

    View details for PubMedCentralID PMC11134207

  • Effects of a personalized nutrition program on cardiometabolic health: a randomized controlled trial. Nature medicine Bermingham, K. M., Linenberg, I., Polidori, L., Asnicar, F., Arrè, A., Wolf, J., Badri, F., Bernard, H., Capdevila, J., Bulsiewicz, W. J., Gardner, C. D., Ordovas, J. M., Davies, R., Hadjigeorgiou, G., Hall, W. L., Delahanty, L. M., Valdes, A. M., Segata, N., Spector, T. D., Berry, S. E. 2024


    Large variability exists in people's responses to foods. However, the efficacy of personalized dietary advice for health remains understudied. We compared a personalized dietary program (PDP) versus general advice (control) on cardiometabolic health using a randomized clinical trial. The PDP used food characteristics, individual postprandial glucose and triglyceride (TG) responses to foods, microbiomes and health history, to produce personalized food scores in an 18-week app-based program. The control group received standard care dietary advice (US Department of Agriculture Guidelines for Americans, 2020-2025) using online resources, check-ins, video lessons and a leaflet. Primary outcomes were serum low-density lipoprotein cholesterol and TG concentrations at baseline and at 18 weeks. Participants (n = 347), aged 41-70 years and generally representative of the average US population, were randomized to the PDP (n = 177) or control (n = 170). Intention-to-treat analysis (n = 347) between groups showed significant reduction in TGs (mean difference = -0.13 mmol l-1; log-transformed 95% confidence interval = -0.07 to -0.01, P = 0.016). Changes in low-density lipoprotein cholesterol were not significant. There were improvements in secondary outcomes, including body weight, waist circumference, HbA1c, diet quality and microbiome (beta-diversity) (P < 0.05), particularly in highly adherent PDP participants. However, blood pressure, insulin, glucose, C-peptide, apolipoprotein A1 and B, and postprandial TGs did not differ between groups. No serious intervention-related adverse events were reported. Following a personalized diet led to some improvements in cardiometabolic health compared to standard dietary advice. registration: NCT05273268 .

    View details for DOI 10.1038/s41591-024-02951-6

    View details for PubMedID 38714898

    View details for PubMedCentralID 5407851

  • Toward Heart-Healthy and Sustainable Cities: A Policy Statement From the American Heart Association CIRCULATION Rajagopalan, S., Ramaswami, A., Bhatnagar, A., Brook, R. D., Fenton, M., Gardner, C., Neff, R., Russell, A. G., Seto, K. C., Whitsel, L. P., Amer Heart Assoc Council Hyperten, Council Lifestyle Cardiometab Hlth, Council Peripheral Vasc Dis, Council Lifelong Congenital Heart, Council Cardiovasc Surg Anesthesia, Amer Heart Assoc Advocacy Coord 2024; 149 (15): e1067-e1089


    Nearly 56% of the global population lives in cities, with this number expected to increase to 6.6 billion or >70% of the world's population by 2050. Given that cardiometabolic diseases are the leading causes of morbidity and mortality in people living in urban areas, transforming cities and urban provisioning systems (or urban systems) toward health, equity, and economic productivity can enable the dual attainment of climate and health goals. Seven urban provisioning systems that provide food, energy, mobility-connectivity, housing, green infrastructure, water management, and waste management lie at the core of human health, well-being, and sustainability. These provisioning systems transcend city boundaries (eg, demand for food, water, or energy is met by transboundary supply); thus, transforming the entire system is a larger construct than local urban environments. Poorly designed urban provisioning systems are starkly evident worldwide, resulting in unprecedented exposures to adverse cardiometabolic risk factors, including limited physical activity, lack of access to heart-healthy diets, and reduced access to greenery and beneficial social interactions. Transforming urban systems with a cardiometabolic health-first approach could be accomplished through integrated spatial planning, along with addressing current gaps in key urban provisioning systems. Such an approach will help mitigate undesirable environmental exposures and improve cardiovascular and metabolic health while improving planetary health. The purposes of this American Heart Association policy statement are to present a conceptual framework, summarize the evidence base, and outline policy principles for transforming key urban provisioning systems to heart-health and sustainability outcomes.

    View details for DOI 10.1161/CIR.0000000000001217

    View details for Web of Science ID 001233579200004

    View details for PubMedID 38436070

  • Exploring Biases of the Healthy Eating Index and Alternative Healthy Eating Index when Scoring Low-Carbohydrate and Low-Fat Diets. Journal of the Academy of Nutrition and Dietetics Hauser, M. E., Hartle, J. C., Landry, M. J., Fielding-Singh, P., Shih, C. W., Qin, F., Rigdon, J., Gardner, C. D. 2024


    The Healthy Eating Index 2010 (HEI-2010) and Alternative Healthy Eating Index 2010 (AHEI-2010) are commonly used to measure dietary quality in research settings. Neither index is designed specifically to compare diet quality between Low-Carbohydrate (LC) and Low-Fat (LF) diets. It is unknown if biases exist in making these comparisons.The aim was to determine whether HEI-2010 and AHEI-2010 contain biases when scoring LC and LF diets.Secondary analyses of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) weight loss trial were conducted. The trial was conducted in the San Francisco Bay Area of California and occurred between January 2013 and May 2016. Three approaches were used to investigate whether biases existed for HEI-2010 and AHEI-2010 when scoring LC and LF diets./Setting: DIETFITS participants were assigned to follow healthy low-carbohydrate (HLC) or healthy low-fat (HLF) diets for 12 months (N=609).Mean diet quality index scores for each diet were measured.Approach 1 examined both diet quality indices' scoring criteria. Approach 2 compared scores garnered by exemplary quality LC and LF menus created by registered dietitians. Approach 3 used two-sided t-tests to compare the HEI-2010 and AHEI-2010 scores calculated from 24-hour dietary recalls of DIETFITS trial participants (N=608).Scoring criteria for both HEI-2010 (100 possible points) and AHEI-2010 (110 possible points) were estimated to favor a LF diet by 10 points. Mean scores for exemplary quality LF menus were higher than for LC menus using both HEI-2010 (91.8 vs. 76.8) and AHEI-2010 (71.7 vs. 64.4, adjusted to 100 possible points). DIETFITS participants assigned to a HLF diet scored significantly higher on HEI and AHEI than those assigned to a HLC diet at 3, 6, and 12-months (all p<0.001). Mean baseline scores were lower than mean scores at all follow-up time points regardless of diet assignment or diet quality index used.Commonly used diet quality indices, HEI-2010 and AHEI-2010, showed biases toward LF versus LC diets. However, both indices detected expected changes in diet quality within each diet, with HEI-2010 yielding greater variation in scores. Findings support the use of these indices in measuring diet quality differences within, but not between, LC and LF diets.

    View details for DOI 10.1016/j.jand.2024.02.014

    View details for PubMedID 38423509

  • Changes in Soluble LDL Receptor and Lipoprotein Fractions in Response to Diet in the DIETFITS Weight Loss Study. Journal of lipid research Krauss, R. M., Fisher, L. M., King, S. M., Gardner, C. D. 2024: 100503


    Circulating levels of the soluble ligand binding ectodomain of the LDL receptor (sLDLR) that is proteolytically cleaved from the cell surface have been shown to correlate with plasma triglycerides, but the lipid and lipoprotein effects of longitudinal changes in sLDLR have not been examined. We sought to assess associations between changes in sLDLR and detailed lipoprotein measurements between baseline and six months in participants in the DIETFITS weight loss trial who were randomly assigned to the low-fat (n=225) or low-carbohydrate (n=236) diet arms. sLDLR was assayed using a proteomic procedure, lipids and apoprotein (apo) B and apoAI were measured by standard assays, and lipoprotein particle subfractions were quantified by ion mobility methodology. Changes in sLDLR were significantly positively associated with changes in plasma cholesterol, triglycerides, apoB, large and medium size very low-density lipoproteins (VLDL), and small and very small LDL, and inversely with changes in large LDL and HDL. The lipoprotein subfraction associations with sLDLR were independent of age, sex, diet, and BMI, but all except for large LDL were reduced to insignificance when adjusted for triglyceride change. Principal component (PC) analysis identified three independent clusters of changes in lipoprotein subfractions that accounted for 78% of their total variance. Change in sLDLR was most strongly correlated with change in the PC that was loaded positively with large VLDL and small and very small LDL, and negatively with large LDL and HDL. In conclusion, sLDLR is a component of a cluster of lipids and lipoproteins that are characteristic of atherogenic dyslipidemia.

    View details for DOI 10.1016/j.jlr.2024.100503

    View details for PubMedID 38246235

  • Corrigendum: Weight, insulin resistance, blood lipids, and diet quality changes associated with ketogenic and ultra low-fat dietary patterns: a secondary analysis of the DIETFITS randomized clinical trial. Frontiers in nutrition Aronica, L., Landry, M. J., Rigdon, J., Gardner, C. D. 2023; 10: 1275498


    [This corrects the article DOI: 10.3389/fnut.2023.1220020.].

    View details for DOI 10.3389/fnut.2023.1275498

    View details for PubMedID 37876614

    View details for PubMedCentralID PMC10593439

  • Editorial: Achieving health equity: sustainability of plant-based diets for human and planetary health. Frontiers in public health Gardner, C. D., Policastro, P., Wang, M. C. 2023; 11: 1285161

    View details for DOI 10.3389/fpubh.2023.1285161

    View details for PubMedID 37841721

    View details for PubMedCentralID PMC10569582

  • Effects of an educational planetary plate graphic on meat consumption in aStanford University dining hall: a randomized controlled trial. BMC nutrition Marcone, A. L., Darmstadt, G. L., Challamel, G. A., Mathur, M. B., Gardner, C. D. 2023; 9 (1): 106


    BACKGROUND: Assess the impact of an educational Planetary Health Plate (PHP) graphic on meat-related dietary choices of Stanford University dining hall patrons using a randomized controlled trial crossover design. All patrons entering the dining hall during study periods were enrolled as participants. Control, n=631; PHP, n=547.METHODS: Compare dietary behavior without signage to behavior while exposed to PHP during four equivalent dinner meals. The primary outcome was total meat-dish weight adjusted for the number of people entering the dining hall. Secondary outcomes included the number of meat-dish servings and average meat-dish serving weight. Analysis using T-tests, Poisson generalized linear model.RESULTS: Differences in total meat-dish weight, (1.54kg; 95% Confidence Interval [CI]=-4.41,1.33; P=.19) and average meat-dish serving weight (0.03kg; 95% CI=0.00, 0.06; P=.07) between PHP and control patrons did not reach significance. The rate at which PHP patrons took meat was significantly lower (Incidence Rate Ratio 0.80; 95% CI=0.71, 0.91; P<.001).CONCLUSION: Exposure to an educational plate graphic decreased the proportion of patrons taking meat but had no impact on total meat consumption or meat-dish serving weight. Statistical methods used in this study may inform future investigations on dietary change in the dining hall setting. Further research on the role of educational signage in influencing dietary behavior is warranted, with an aim to improve human health and environmental sustainability.TRIAL REGISTRATION:, NCT05565859, registered 4 October 2022.

    View details for DOI 10.1186/s40795-023-00764-3

    View details for PubMedID 37749609

  • Weight, insulin resistance, blood lipids, and diet quality changes associated with ketogenic and ultra low-fat dietary patterns: a secondary analysis of the DIETFITS randomized clinical trial. Frontiers in nutrition Aronica, L., Landry, M. J., Rigdon, J., Gardner, C. D. 2023; 10: 1220020


    The DIETFITS trial reported no significant difference in 12-month weight loss between a healthy low-fat and healthy low-carbohydrate diet. Participants were instructed to restrict fat or carbohydrates to levels consistent with a ketogenic or ultra low-fat diet for 2  months and to subsequently increase intakes until they achieved a comfortable maintenance level.To compare 3- and 12-month changes in body weight and cardiometabolic risk factors between a subsample of participants who reported 3-month fat or carbohydrates intakes consistent with either a ketogenic-like diet (KLD) or ultra low-fat diet (ULF).3-month and 12-month weight and risk factor outcomes were compared between KLD (n = 18) and ULF (n = 21) sub-groups of DIETFITS participants (selected from n = 609, healthy overweight/obese, aged 18-50  years).Less than 10% of DIETFITS participants met KLD or ULF criteria at 3-months. Both groups achieved similar weight loss and insulin resistance improvements at 3-months and maintained them at 12- months. Significant differences at 3-months included a transient ~12% increase in LDL cholesterol (LDL-C) for KLD with a concomitant greater reduction in log(TG/HDL), a measure of LDL-C's atherogenic potential. The latter was maintained at 12-months, despite substantial diet recidivism for both groups, whereas LDL-C levels were similar for ULF at baseline and 12-months. KLD participants achieved and maintained the greatest reductions in added sugars and refined grains at 3- months and 12-months, whereas ULF participants reported a 50% increase in refined grains intake from baseline to 12-months.Among the ~10% of study participants that achieved the most extreme restriction of dietary fat vs. carbohydrate after 3  months, weight loss and improvement in insulin sensitivity were substantial and similar between groups. At 12  months, after considerable dietary recidivism, the few significant differences in diet quality and blood lipid parameters tended to favor KLD over ULF.

    View details for DOI 10.3389/fnut.2023.1220020

    View details for PubMedID 37502720

    View details for PubMedCentralID PMC10369076

  • Not All Ultra-Processed Foods Are Created Equal: A Case for Advancing Research and Policy That Balances Health and Nutrition Security. Diabetes care Vadiveloo, M. K., Gardner, C. D. 2023; 46 (7): 1327-1329

    View details for DOI 10.2337/dci23-0018

    View details for PubMedID 37339348

  • Challenging obesity and sex based differences in resting energy expenditure using allometric modeling, a sub-study of the DIETFITS clinical trial. Clinical nutrition ESPEN Haddad, F., Li, X., Perelman, D., Santana, E. J., Kuznetsova, T., Cauwenberghs, N., Busque, V., Contrepois, K., Snyder, M. P., Leonard, M. B., Gardner, C. 2023; 53: 43-52


    BACKGROUND & AIMS: Resting energy expenditure (REE) is a major component of energy balance. While REE is usually indexed to total body weight (BW), this may introduce biases when assessing REE in obesity or during weight loss intervention. The main objective of the study was to quantify the bias introduced by ratiometric scaling of REE using BW both at baseline and following weight loss intervention.DESIGN: Participants in the DIETFITS Study (Diet Intervention Examining The Factors Interacting with Treatment Success) who completed indirect calorimetry and dual-energy X-ray absorptiometry (DXA) were included in the study. Data were available in 438 participants at baseline, 340at 6 months and 323at 12 months. We used multiplicative allometric modeling based on lean body mass (LBM) and fat mass (FM) to derive body size independent scaling of REE. Longitudinal changes in indexed REE were then assessed following weight loss intervention.RESULTS: A multiplicative model including LBM, FM, age, Black race and the double product (DP) of systolic blood pressure and heart rate explained 79% of variance in REE. REE indexed to [LBM0.66*FM0.066] was body size and sex independent (p=0.91 and p=0.73, respectively) in contrast to BW based indexing which showed a significant inverse relationship to BW (r=-0.47 for female and r=-0.44 for male, both p<0.001). When indexed to BW, significant baseline differences in REE were observed between male and female (p<0.001) and between individuals who are overweight and obese (p<0.001) while no significant differences were observed when indexed to REE/[LBM0.66*FM0.066], p>0.05). Percentage predicted REE adjusted for LBM, FM and DP remained stable following weight loss intervention (p=0.614).CONCLUSION: Allometric scaling of REE based on LBM and FM removes body composition-associated biases and should be considered in obesity and weight-based intervention studies.

    View details for DOI 10.1016/j.clnesp.2022.11.015

    View details for PubMedID 36657929

  • Friend or Foe? The Role of Animal-Source Foods in Healthy and Environmentally Sustainable Diets. The Journal of nutrition Beal, T., Gardner, C. D., Herrero, M., Iannotti, L. L., Merbold, L., Nordhagen, S., Mottet, A. 2023; 153 (2): 409-425


    Scientific and political discussions around the role of animal-source foods (ASFs) in healthy and environmentally sustainable diets are often polarizing. To bring clarity to this important topic, we critically reviewed the evidence on the health and environmental benefits and risks of ASFs, focusing on primary trade-offs and tensions, and summarized the evidence on alternative proteins and protein-rich foods. ASFs are rich in bioavailable nutrients commonly lacking globally and can make important contributions to food and nutrition security. Many populations in Sub-Saharan Africa and South Asia could benefit from increased consumption of ASFs through improved nutrient intakes and reduced undernutrition. Where consumption is high, processed meat should be limited, and red meat and saturated fat should be moderated to lower noncommunicable disease risk-this could also have cobenefits for environmental sustainability. ASF production generally has a large environmental impact; yet, when produced at the appropriate scale and in accordance with local ecosystems and contexts, ASFs can play an important role in circular and diverse agroecosystems that, in certain circumstances, can help restore biodiversity and degraded land and mitigate greenhouse gas emissions from food production. The amount and type of ASF that is healthy and environmentally sustainable will depend on the local context and health priorities and will change over time as populations develop, nutritional concerns evolve, and alternative foods from new technologies become more available and acceptable. Efforts by governments and civil society organizations to increase or decrease ASF consumption should be considered in light of the nutritional and environmental needs and risks in the local context and, importantly, integrally involve the local stakeholders impacted by any changes. Policies, programs, and incentives are needed to ensure best practices in production, curb excess consumption where high, and sustainably increase consumption where low.

    View details for DOI 10.1016/j.tjnut.2022.10.016

    View details for PubMedID 36894234

  • Randomized controlled trial demonstrates response to a probiotic intervention for metabolic syndrome that may correspond to diet. Gut microbes Wastyk, H. C., Perelman, D., Topf, M., Fragiadakis, G. K., Robinson, J. L., Sonnenburg, J. L., Gardner, C. D., Sonnenburg, E. D. 2023; 15 (1): 2178794


    An individual's immune and metabolic status is coupled to their microbiome. Probiotics offer a promising, safe route to influence host health, possibly via the microbiome. Here, we report an 18-week, randomized prospective study that explores the effects of a probiotic vs. placebo supplement on 39 adults with elevated parameters of metabolic syndrome. We performed longitudinal sampling of stool and blood to profile the human microbiome and immune system. While we did not see changes in metabolic syndrome markers in response to the probiotic across the entire cohort, there were significant improvements in triglycerides and diastolic blood pressure in a subset of probiotic arm participants. Conversely, the non-responders had increased blood glucose and insulin levels over time. The responders had a distinct microbiome profile at the end of the intervention relative to the non-responders and placebo arm. Importantly, diet was a key differentiating factor between responders and non-responders. Our results show participant-specific effects of a probiotic supplement on improving parameters of metabolic syndrome and suggest that dietary factors may enhance stability and efficacy of the supplement.

    View details for DOI 10.1080/19490976.2023.2178794

    View details for PubMedID 36803658

  • Distinct factors associated with short-term and long-term weight loss induced by low-fat or low-carbohydrate diet intervention. Cell reports. Medicine Li, X., Perelman, D., Leong, A. K., Fragiadakis, G., Gardner, C. D., Snyder, M. P. 2022: 100870


    To understand what determines the success of short- and long-term weight loss, we conduct a secondary analysis of dietary, metabolic, and molecular data collected from 609 participants before, during, and after a 1-year weight-loss intervention with either a healthy low-carbohydrate (HLC) or a healthy low-fat (HLF) diet. Through systematic analysis of multidomain datasets, we find that dietary adherence and diet quality, not just caloric restriction, are important for short-term weight loss in both diets. Interestingly, we observe minimal dietary differences between those who succeeded in long-term weight loss and those who did not. Instead, proteomic and gut microbiota signatures significantly differ between these two groups at baseline. Moreover, the baseline respiratory quotient may suggest a specific diet for better weight-loss outcomes. Overall, the identification of these dietary, molecular, and metabolic factors, common or unique to the HLC and HLF diets, provides a roadmap for developing individualized weight-loss strategies.

    View details for DOI 10.1016/j.xcrm.2022.100870

    View details for PubMedID 36516846

  • Development and evaluation of a novel dietary bisphenol A (BPA) exposure risk tool. BMC nutrition Hartle, J. C., Zawadzki, R. S., Rigdon, J., Lam, J., Gardner, C. D. 2022; 8 (1): 143


    Exposure to endocrine disrupting chemicals such as bisphenol A (BPA) is primarily from the diet through canned foods. Characterizing dietary exposures can be conducted through biomonitoring and dietary surveys; however, these methods can be time-consuming and challenging to implement.We developed a novel dietary exposure risk questionnaire to evaluate BPA exposure and compared these results to 24-hr dietary recall data from participants (n = 404) of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study, a dietary clinical trial, to validate questionnaire responses. High BPA exposure foods were identified from the dietary recalls and used to estimate BPA exposure. Linear regression models estimated the association between exposure to BPA and questionnaire responses. A composite risk score was developed to summarize questionnaire responses.In questionnaire data, 65% of participants ate canned food every week. A composite exposure score validated that the dietary exposure risk questionnaire captured increasing BPA exposure. In the linear regression models, utilizing questionnaire responses vs. 24-hr dietary recall data, participants eating canned foods 1-2 times/week (vs. never) consumed 0.78 more servings (p < 0.001) of high BPA exposure foods, and those eating canned foods 3+ times/week (vs. never) consumed 0.89 more servings (p = 0.013) of high BPA exposure foods. Participants eating 3+ packaged items/day (vs. never) consumed 62.65 more total grams of high BPA exposure food (p = 0.036).Dietary exposure risk questionnaires may provide an efficient alternative approach to 24-hour dietary recalls to quantify dietary BPA exposure with low participant burden.The trial was prospectively registered at as NCT01826591 on April 8, 2013.

    View details for DOI 10.1186/s40795-022-00634-4

    View details for PubMedID 36474269

  • SWAP-MEAT Athlete (study with appetizing plant-food, meat eating alternatives trial) - investigating the impact of three different diets on recreational athletic performance: a randomized crossover trial. Nutrition journal Roberts, A. K., Busque, V., Robinson, J. L., Landry, M. J., Gardner, C. D. 2022; 21 (1): 69


    BACKGROUND: Plant-based diets are known to be beneficial for cardiovascular health and promote environmental sustainability. However, many athletes avoid plant-based diets due to concerns of protein inadequacy.OBJECTIVES: To investigate the impact of two predominately plant-based diets-whole food plant-based (WFPB) and plant-based meat alternatives (PBMA)-vs. an omnivorous diet, favoring red meat and poultry (Animal), on endurance and muscular strength.METHODS: 12 recreational runners and 12 resistance trainers were assigned to three diets-WFPB, PBMA, and Animal-for 4weeks each, in random order. Primary outcomes for runners (12-minute timed run) and resistance trainers (composite machine strength) were collected at baseline and after diets, along with secondary performance outcomes and dietary data.RESULTS: 22 recreational athletes completed the study (age: 26.2±4.4years; sex: 10 female, 12 male; BMI: 23.1±2.4kg/m2). Mean differences in 12-minute timed run - WFPB vs. Animal (-23.4m; 95% CI: -107 to 60.0m) and PBMA vs. Animal (-2.9m; 95% CI: -119 to 113m) - were not significant. Mean percent differences in composite machine strength - WFPB vs. Animal (-2.7%; 95% CI: -5.8 to 0.4% and PBMA vs. Animal (-0.7%; 95% CI: -3.5 to 2.2%) - were not significant. Average protein intake for all diets met International Society for Sports Nutrition recommendations.CONCLUSIONS: Our findings suggest recreational athletes can maintain athletic performance on both an omnivorous diet and two diets that are predominately plant-based.TRIAL REGISTRATION: NCT05472701. Retrospectively registered.

    View details for DOI 10.1186/s12937-022-00820-x

    View details for PubMedID 36384651

  • Assessing the effects of alternative plant-based meats v. animal meats on biomarkers of inflammation: a secondary analysis of the SWAP-MEAT randomized crossover trial JOURNAL OF NUTRITIONAL SCIENCE Crimarco, A., Landry, M. J., Carter, M. M., Gardner, C. D. 2022; 11
  • Reply to T Kalayjian and EC Westman. The American journal of clinical nutrition Gardner, C. D., Landry, M. J., Aronica, L., Cunanan, K. M., Kim, S. H. 2022

    View details for DOI 10.1093/ajcn/nqac201

    View details for PubMedID 35883212

  • The quest to advance assessment of dietary intake: metabolomic meat markers. The American journal of clinical nutrition Vadiveloo, M. K., Landry, M. J., Gardner, C. D. 2022

    View details for DOI 10.1093/ajcn/nqac143

    View details for PubMedID 35731849

  • Short-Term Dairy Product Elimination and Reintroduction Minimally Perturbs the Gut Microbiota in Self-Reported Lactose-Intolerant Adults. mBio Smith, C. J., Dethlefsen, L., Gardner, C., Nguyen, L., Feldman, M., Costello, E. K., Kolodny, O., Relman, D. A. 2022: e0105122


    An outstanding question regarding the human gut microbiota is whether and how microbiota-directed interventions influence host phenotypic traits. Here, we employed a dietary intervention to probe this question in the context of lactose intolerance. To assess the effects of dietary dairy product elimination and (re)introduction on the microbiota and host phenotype, we studied 12 self-reported mildly lactose-intolerant adults with triweekly collection of fecal samples over a 12-week study period: 2weeks of baseline diet, 4weeks of dairy product elimination, and 6weeks of gradual whole cow milk (re)introduction. Of the 12 subjects, 6 reported either no dairy or only lactose-free dairy product consumption. A clinical assay for lactose intolerance, the hydrogen breath test, was performed before and after each of these three study phases, and 16S rRNA gene amplicon sequencing was performed on all fecal samples. We found that none of the subjects showed change in a clinically defined measure of lactose tolerance. Similarly, fecal microbiota structure resisted modification. Although the mean fraction of the genus Bifidobacterium, a group known to metabolize lactose, increased slightly with milk (re)introduction (from 0.0125 to 0.0206; Wilcoxon P=0.068), the overall structure of each subject's gut microbiota remained highly individualized and largely stable in the face of diet manipulation. IMPORTANCE Lactose intolerance is a gastrointestinal disorder diagnosed with a lactose hydrogen breath test. Lifestyle changes such as diet interventions can impact the gut microbiome; however, the role of the microbiome in lactose intolerance is unclear. Our study assessed the effects of a 12-week dietary dairy product elimination and (re)introduction on the microbiome and clinical lactose intolerance status in 12 adult self-reported lactose-intolerant individuals. We found each subject's gut microbiome remained highly individualized and largely stable in the face of this diet manipulation. We also report that none of the subjects showed change in a clinically defined measure of lactose tolerance.

    View details for DOI 10.1128/mbio.01051-22

    View details for PubMedID 35695459

  • Genetic Predictors of Change in Waist Circumference and Waist-to-Hip Ratio With Lifestyle Intervention: The Trans-NIH Consortium for Genetics of Weight Loss Response to Lifestyle Intervention DIABETES McCaffery, J. M., Jablonski, K. A., Pan, Q., Astrup, A., Christiansen, M., Corella, D., Corso, L. L., Florez, J. C., Franks, P. W., Gardner, C., Hansen, T., Kilpelainen, T. O., Knowler, W. C., Lindstrom, J., Saris, W. M., Sorensen, T. A., Tuomilehto, J., Uusitupa, M., Wing, R. R., Agurs-Collins, T. 2022; 71 (4): 669-676


    Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with waist circumference (WC) and waist-to-hip ratio (WHR) adjusted for BMI (WCadjBMI and WHRadjBMI), but it remains unclear whether these SNPs relate to change in WCadjBMI or WHRadjBMI with lifestyle intervention for weight loss. We hypothesized that polygenic scores (PS) comprised of 59 SNPs previously associated with central adiposity would predict less of a reduction in WCadjBMI or WHRadjBMI at 8-10 weeks in two lifestyle intervention trials, NUGENOB and DiOGenes, and at 1 year in five lifestyle intervention trials, Look AHEAD, Diabetes Prevention Program, Diabetes Prevention Study, DIETFITS, and PREDIMED-Plus. One-SD higher PS related to a smaller 1-year change in WCadjBMI in the lifestyle intervention arms at year 1 and thus predicted poorer response (β = 0.007; SE = 0.003; P = 0.03) among White participants overall and in White men (β = 0.01; SE = 0.004; P = 0.01). At average weight loss, this amounted to 0.20-0.28 cm per SD. No significant findings emerged in White women or African American men for the 8-10-week outcomes or for WHRadjBMI. Findings were heterogeneous in African American women. These results indicate that polygenic risk estimated from these 59 SNPs relates to change in WCadjBMI with lifestyle intervention, but the effects are small and not of sufficient magnitude to be clinically significant.

    View details for DOI 10.2337/db21-0741

    View details for Web of Science ID 000835317500010

    View details for PubMedID 35043141

    View details for PubMedCentralID PMC9114721

  • Effectiveness of a Theory-Informed Documentary to Reduce Consumption of Meat and Animal Products: Three Randomized Controlled Experiments. Nutrients Mathur, M. B., Peacock, J. R., Robinson, T. N., Gardner, C. D. 1800; 13 (12)


    Several societal issues could be mitigated by reducing global consumption of meat and animal products (MAP). In three randomized, controlled experiments (n=217 to 574), we evaluated the effects of a documentary that presents health, environmental, and animal welfare motivations for reducing MAP consumption. Study 1 assessed the documentary's effectiveness at reducing reported MAP consumption after 12 days. This study used methodological innovations to minimize social desirability bias, a widespread limitation of past research. Study 2 investigated discrepancies between the results of Study 1 and those of previous studies by further examining the role of social desirability bias. Study 3 assessed the documentary's effectiveness in a new population anticipated to be more responsive and upon enhancing the intervention content. We found that the documentary did not decrease reported MAP consumption when potential social desirability bias was minimized (Studies 1 and 3). The documentary also did not affect consumption among participants whose demographics suggested they might be more receptive (Study 3). However, the documentary did substantially increase intentions to reduce consumption, consistent with past studies (Studies 2 and 3). Overall, we conclude that some past studies of similar interventions may have overestimated effects due to methodological biases. Novel intervention strategies to reduce MAP consumption may be needed.

    View details for DOI 10.3390/nu13124555

    View details for PubMedID 34960107

  • Diet and lifestyle behaviour disruption related to the pandemic was varied and bidirectional among US and UK adults participating in the ZOE COVID Study NATURE FOOD Mazidi, M., Leeming, E. R., Merino, J., Nguyen, L. H., Selvachandran, S., Pujal, J., Maher, T., Kade, K., Murray, B., Graham, M. S., Sudre, C. H., Wolf, J., Hu, C., Drew, D. A., Steves, C. J., Ourselin, S., Gardner, C., Spector, T. D., Chan, A. T., Franks, P. W., Gibson, R., Berry, S. E. 2021
  • Diet and lifestyle behaviour disruption related to the pandemic was varied and bidirectional among US and UK adults participating in the ZOE COVID Study. Nature food Mazidi, M., Leeming, E. R., Merino, J., Nguyen, L. H., Selvachandran, S., Pujal, J. C., Maher, T., Kadé, K., Murray, B., Graham, M. S., Sudre, C. H., Wolf, J., Hu, C., Drew, D. A., Steves, C. J., Ourselin, S., Gardner, C., Spector, T. D., Chan, A. T., Franks, P. W., Gibson, R., Berry, S. E. 2021; 2 (12): 957-969


    Evidence of the impact of the COVID-19 pandemic on health behaviours in the general population is limited. In this retrospective longitudinal study including UK and US participants, we collected diet and lifestyle data pre-pandemic (896,286) and peri-pandemic (291,871) using a mobile health app, and we computed a bidirectional health behaviour disruption index. Disruption of health behaviour was higher in younger, female and socio-economically deprived participants. Loss in body weight was greater in highly disrupted individuals than in those with low disruption. There were large inter-individual changes observed in 46 health and diet behaviours measured peri-pandemic compared with pre-pandemic, but no mean change in the total population. Individuals most adherent to less healthy pre-pandemic health behaviours improved their diet quality and weight compared with those reporting healthier pre-pandemic behaviours, irrespective of relative deprivation; therefore, for a proportion of the population, the pandemic may have provided an impetus to improve health behaviours. Public policies to tackle health inequalities widened by the pandemic should continue to prioritize diet and physical activity for all, as well as more targeted approaches to support younger females and those living in economically deprived areas.

    View details for DOI 10.1038/s43016-021-00398-3

    View details for PubMedID 37118259

    View details for PubMedCentralID 7513993

  • Interaction of Diet/Lifestyle Intervention and TCF7L2 Genotype on Glycemic Control and Adiposity among Overweight or Obese Adults: Big Data from Seven Randomized Controlled Trials Worldwide. Health data science Huang, T., Zhuang, Z., Heianza, Y., Sun, D., Ma, W., Wang, W., Gao, M., Fang, Z., Ros, E., Del Gobbo, L. C., Salas-Salvadó, J., Martínez-González, M. A., Polak, J., Laakso, M., Astrup, A., Langin, D., Hager, J., Hul, G., Hansen, T., Pedersen, O., Oppert, J. M., Saris, W. H., Arner, P., Cofán, M., Rajaram, S., Tuomilehto, J., Lindström, J., de Mello, V. D., Stancacova, A., Uusitupa, M., Svendstrup, M., Sørensen, T. I., Gardner, C. D., Sabaté, J., Corella, D., Martinez, J. A., Qi, L. 2021; 2021: 9897048


    Objective. The strongest locus which associated with type 2 diabetes (T2D) by the common variant rs7903146 is the transcription factor 7-like 2 gene (TCF7L2). We aimed to quantify the interaction of diet/lifestyle interventions and the genetic effect of TCF7L2 rs7903146 on glycemic traits, body weight, or waist circumference in overweight or obese adults in several randomized controlled trials (RCTs).Methods. From October 2016 to May 2018, a large collaborative analysis was performed by pooling individual-participant data from 7 RCTs. These RCTs reported changes in glycemic control and adiposity of the variant rs7903146 after dietary/lifestyle-related interventions in overweight or obese adults. Gene treatment interaction models which used the genetic effect encoded by the allele dose and common covariates were applicable to individual participant data in all studies.Results. In the joint analysis, a total of 7 eligible RCTs were included (n=4,114). Importantly, we observed a significant effect modification of diet/lifestyle-related interventions on the TCF7L2 variant rs7903146 and changes in fasting glucose. Compared with the control group, diet/lifestyle interventions were related to lower fasting glucose by -3.06 (95% CI, -5.77 to -0.36) mg/dL (test for heterogeneity and overall effect: I2=45.1%, p<0.05; z=2.20, p=0.028) per one copy of the TCF7L2 T risk allele. Furthermore, regardless of genetic risk, diet/lifestyle interventions were associated with lower waist circumference. However, there was no significant change for diet/lifestyle interventions in other glycemic control and adiposity traits per one copy of TCF7L2 risk allele.Conclusions. Our findings suggest that carrying the TCF7L2 T risk allele may have a modestly greater benefit for specific diet/lifestyle interventions to improve the control of fasting glucose in overweight or obese adults.

    View details for DOI 10.34133/2021/9897048

    View details for PubMedID 38487510

    View details for PubMedCentralID PMC10904069

  • Changes in Ultra-Processed Food Consumption and Lifestyle Behaviors Following COVID-19 Shelter-in-Place: A Retrospective Study. Foods (Basel, Switzerland) Sobba, W., Landry, M. J., Cunanan, K. M., Marcone, A., Gardner, C. D. 2021; 10 (11)


    Ultra-processed food (UPF) consumption poses a potential risk to public health and may be related to shelter-in-place orders. This study utilized the level of food processing as a lens by which to examine the relationships between diet, weight change, and lifestyle changes (including cooking, snacking, and sedentary activity) that occurred during regional shelter-in-place orders. This study used a cross-sectional, retrospective survey (n = 589) to assess baseline demographics, changes in lifestyle behaviors using a Likert scale, and changes in dietary behaviors using a modified food frequency questionnaire from mid-March to May 2020; data were collected in the California Bay Area from August to October 2020. Foods were categorized by level of processing (minimally processed, processed, and ultra-processed) using the NOVA scale. Stepwise multiple linear regression and univariate linear regression models were used to determine the associations between these factors. Increased snacking was positively associated with a change in the percent of the calories derived from UPF and weight gain (beta = 1.0, p < 0.001; beta = 0.8 kg, p < 0.001) and negatively associated with the share of MPF calories consumed (beta = -0.9, p < 0.001). These relationships have public health implications as interventions designed around decreased snacking may positively impact diet and weight management and thereby mitigate negative health outcomes.

    View details for DOI 10.3390/foods10112553

    View details for PubMedID 34828834

  • Ultra-processed Foods, Weight Gain, and Co-morbidity Risk. Current obesity reports Crimarco, A., Landry, M. J., Gardner, C. D. 2021


    PURPOSE OF REVIEW: The purpose of this review is to provide an update on the available data regarding the associations of Ultra-processed food (UPF) consumption with food intake and possible underlying mechanisms relating UPF consumption to weight gain and co-morbidities.RECENT FINDINGS: In primarily observational studies, UPF consumption is consistently associated with an increased risk for weight gain among adults and children and increased risk for adiposity-related co-morbidities in adults. In a single mechanistic study, consumption of UPFs led to increased energy intake and weight gain relative to whole foods. UPFs tend to be more energy-dense than nutrient-dense, and UPF consumption is associated with increased adiposity and co-morbidity risk. These data suggest that recommendations to limit UPF consumption may be beneficial to health - though further mechanistic studies are needed.

    View details for DOI 10.1007/s13679-021-00460-y

    View details for PubMedID 34677812

  • Findings from Diet Comparison Difficult to Interpret in the Absence of Adherence Assessment. Comment on Trico et al. Effects of Low-Carbohydrate versus Mediterranean Diets on Weight Loss, Glucose Metabolism, Insulin Kinetics and beta-Cell Function in Morbidly Obese Individuals. Nutrients 2021, 13, 1345. Nutrients Landry, M. J., Crimarco, A., Gardner, C. D. 2021; 13 (11)


    We read, with interest, the recent publication by Trico et al. [...].

    View details for DOI 10.3390/nu13113694

    View details for PubMedID 34835950

  • Changes in Quantity and Sources of Dietary Fiber from Adopting Healthy Low-Fat vs. Healthy Low-Carb Weight Loss Diets: Secondary Analysis of DIETFITS Weight Loss Diet Study. Nutrients Offringa, L. C., Hartle, J. C., Rigdon, J., Gardner, C. D. 2021; 13 (10)


    The daily intake of dietary fiber is well below the recommended levels in the US. The effect of adopting a low-fat vs. a low-carbohydrate weight loss diet on fiber intake is of interest but not well-documented, especially when both approaches promote high-quality food choices. The objective of this paper is to compare the quantity and sources of dietary fiber between a healthy low-fat (HLF) vs. healthy low-carbohydrate (HLC) diet group when consumed over 12 months in a weight loss diet study. In this secondary analysis of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study, the amount and sources of dietary fiber were examined in generally healthy adults, 18-50 years of age, Body Mass Index (BMI) 28-40 kg/m2, randomized to HLF or HLC for 12 months, who had available 24-h recalls at 0 (n = 609), 3 (n = 549), 6 (n = 491), and 12 (n = 449) months. The dietary intake was estimated by the Nutrition Data System for Research (NDS-R). The sources of fiber were determined for the major food groups. Significantly more total dietary fiber was consumed by HLF at every post-randomization time point, and, at 12 m, was 23.04 ± 9.43 g vs. 18.61 ± 8.12 g for HLF vs. HLC, respectively, p < 0.0001. In both diet groups at 12 months, the highest amount of dietary fiber came from non-starchy vegetables (4.13 ± 3.05 g and 5.13 ± 3.59 g). The other primary sources of fiber at 12 months for the HLF group were from whole grains (3.90 ± 3.13 g) and fruits (3.40 ± 2.87 g), and, for the HLC group, were from plant protein and fat sources, such as nuts and seeds, their butters, and avocados (2.64 ± 2.64 g). In the DIETFITS study, the difference in the total fiber intake for the HLF vs. HLC groups was more modest than expected. The HLC group consumed reasonably high amounts of fiber from high-protein and high fat plant-based sources.

    View details for DOI 10.3390/nu13103625

    View details for PubMedID 34684626

  • Temporal changes in soluble angiotensin-converting enzyme 2 associated with metabolic health, body composition, and proteome dynamics during a weight loss diet intervention: a randomized trial with implications for the COVID-19 pandemic. The American journal of clinical nutrition Cauwenberghs, N., Prunicki, M., Sabovcik, F., Perelman, D., Contrepois, K., Li, X., Snyder, M. P., Nadeau, K. C., Kuznetsova, T., Haddad, F., Gardner, C. D. 2021


    BACKGROUND: Angiotensin-converting enzyme 2 (ACE2) serves protective functions in metabolic, cardiovascular, renal, and pulmonary diseases and is linked to COVID-19 pathology. The correlates of temporal changes in soluble ACE2 (sACE2) remain understudied.OBJECTIVES: We explored the associations of sACE2 with metabolic health and proteome dynamics during a weight loss diet intervention.METHODS: We analyzed 457 healthy individuals (mean±SD age: 39.8±6.6 y) with BMI 28-40kg/m2 in the DIETFITS (Diet Intervention Examining the Factors Interacting with Treatment Success) study. Biochemical markers of metabolic health and 236 proteins were measured by Olink CVDII, CVDIII, and Inflammation I arrays at baseline and at 6 mo during the dietary intervention. We determined clinical and routine biochemical correlates of the diet-induced change in sACE2 (DeltasACE2) using stepwise linear regression. We combined feature selection models and multivariable-adjusted linear regression to identify protein dynamics associated with DeltasACE2.RESULTS: sACE2 decreased on average at 6 mo during the diet intervention. Stronger decline in sACE2 during the diet intervention was independently associated with female sex, lower HOMA-IR and LDL cholesterol at baseline, and a stronger decline in HOMA-IR, triglycerides, HDL cholesterol, and fat mass. Participants with decreasing HOMA-IR (OR: 1.97; 95% CI: 1.28, 3.03) and triglycerides (OR: 2.71; 95% CI: 1.72, 4.26) had significantly higher odds for a decrease in sACE2 during the diet intervention than those without (P≤0.0073). Feature selection models linked DeltasACE2 to changes in alpha-1-microglobulin/bikunin precursor, E-selectin, hydroxyacid oxidase 1, kidney injury molecule 1, tyrosine-protein kinase Mer, placental growth factor, thrombomodulin, and TNF receptor superfamily member 10B. DeltasACE2 remained associated with these protein changes in multivariable-adjusted linear regression.CONCLUSIONS: Decrease in sACE2 during a weight loss diet intervention was associated with improvements in metabolic health, fat mass, and markers of angiotensin peptide metabolism, hepatic and vascular injury, renal function, chronic inflammation, and oxidative stress. Our findings may improve the risk stratification, prevention, and management of cardiometabolic complications.This trial was registered at as NCT01826591.

    View details for DOI 10.1093/ajcn/nqab243

    View details for PubMedID 34375388

  • Benefits of Low Carbohydrate Diets: a Settled Question or Still Controversial? Current obesity reports Landry, M. J., Crimarco, A., Gardner, C. D. 2021


    PURPOSE OF REVIEW: The purpose of this review was to provide an update on the available data on the benefits of low-carbohydrate (low-carb) diets for weight management and type 2 diabetes (T2DM) and determine if low-carb diets were a settled question or still controversial.RECENT FINDINGS: Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials. Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both. There are numerous challenges in trying to draw clear conclusions about efficacy and effectiveness. Short-term vs. long-term effects can differ, which is likely impacted by adherence. Adherence is very different between metabolic chamber or feeding studies vs. free-living. Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water. Benefits for glycemic control need to be balanced with impacts on non-glycemic outcomes such as LDL-cholesterol, the microbiome, and inflammation. It is important to differentiate between low-carb and very-low carbohydrate diets (VLCD). To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM. Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD. Some of the recent, better studies highlighted in this review suggest strategies for resolving these controversies.

    View details for DOI 10.1007/s13679-021-00451-z

    View details for PubMedID 34297345

  • Three Factors That Need to be Addressed More Consistently in Nutrition Studies: "Instead of What?'', "In What Context?'', and "For What?'' AMERICAN JOURNAL OF HEALTH PROMOTION Gardner, C. D., Mehta, T., Bernstein, A., Aronson, D. 2021; 35 (6): 881-882
  • Three Factors That Need to be Addressed More Consistently in Nutrition Studies: "Instead of What?", "In What Context?", and "For What?" American journal of health promotion : AJHP Gardner, C. D., Mehta, T., Bernstein, A., Aronson, D. 2021; 35 (6): 881-882

    View details for DOI 10.1177/08901171211016191d

    View details for PubMedID 34120473

  • A Critical Review of the Study of Neuroprotective Diets to Reduce Cognitive Decline. Nutrients Duplantier, S. C., Gardner, C. D. 2021; 13 (7)


    Alzheimer's disease (AD) and other dementias are now the seventh leading cause of death in the world and are projected to affect 115.4 million people by 2050. Delaying the onset of AD by just five years is estimated to reduce the cost and prevalence of the disease by half. There is no cure for AD nor any drug therapies to halt its progression once the disease begins. Lifestyle choices including diet are being seen as a viable complementary therapy to reduce cognitive decline, the hallmark of AD. Mediterranean, DASH (Dietary Approaches to Stop Hypertension), and MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diets have biological mechanisms supporting their potential neuroprotective benefits, but the findings of study outcomes about these benefits have been inconsistent. This paper analyzed five Randomized Clinical Trials (RCTs) (from 2000 to 2021) and 27 observational studies (from 2010 to 2021) focused on the link between cognitive health and the Mediterranean/DASH/MIND diets to identify gaps and challenges that could lead to inconsistent results. These include a lack of accuracy in assessing food intake, multiple dietary pattern scoring systems, a shifting metric among studies focused on the Mediterranean diet, a lack of standards in the tools used to assess cognitive decline, and studies that were underpowered or had follow-up periods too short to detect cognitive change. Insights from these gaps and challenges are summarized in recommendations for future RCTs, including both pragmatic and explanatory RCTs.

    View details for DOI 10.3390/nu13072264

    View details for PubMedID 34208980

  • Associations of Changes in Blood Lipid Concentrations with Changes in Dietary Cholesterol Intake in the Context of a Healthy Low-Carbohydrate Weight Loss Diet: A Secondary Analysis of the DIETFITS Trial. Nutrients Vergara, M., Hauser, M. E., Aronica, L., Rigdon, J., Fielding-Singh, P., Shih, C. W., Gardner, C. D. 2021; 13 (6)


    In 2015, the Dietary Guidelines for Americans (DGA) eliminated the historical upper limit of 300 mg of dietary cholesterol/day and shifted to a more general recommendation that cholesterol intake should be limited. The primary aim of this secondary analysis of the Diet Intervention Examining the Factors Interacting With Treatment Success (DIETFITS) weight loss diet trial was to evaluate the associations between 12-month changes in dietary cholesterol intake (mg/day) and changes in plasma lipids, particularly low-density lipoprotein (LDL) cholesterol for those following a healthy low-carbohydrate (HLC) diet. Secondary aims included examining high-density lipoprotein (HDL) cholesterol and triglycerides and changes in refined grains and added sugars. The DIETFITS trial randomized 609 healthy adults aged 18-50 years with body mass indices of 28-40 kg/m2 to an HLC or healthy low-fat (HLF) diet for 12 months. Linear regressions examined the association between 12-month change in dietary cholesterol intake and plasma lipids in 208 HLC participants with complete diet and lipid data, adjusting for potential confounding variables. Baseline dietary cholesterol intake was 322 ± 173 (mean ± SD). At 12 months, participants consumed an average of 460 ± 227 mg/day of dietary cholesterol; 76% consumed over the previously recommended limit of 300 mg/day. Twelve-month changes in cholesterol intake were not significantly associated with 12-month changes in LDL-C, HDL-C, or triglycerides. Diet recall data suggested participants' increase in dietary cholesterol was partly due to replacing refined grains and sugars with eggs. An increase in daily dietary cholesterol intake to levels substantially above the previous 300 mg upper limit was not associated with a negative impact on lipid profiles in the setting of a healthy, low-carbohydrate weight loss diet.

    View details for DOI 10.3390/nu13061935

    View details for PubMedID 34200027

  • Interventions to Reduce Meat Consumption by Appealing to Animal Welfare: Meta-Analysis and Evidence-Based Recommendations. Appetite Mathur, M. B., Peacock, J., Reichling, D. B., Nadler, J., Bain, P. A., Gardner, C. D., Robinson, T. N. 2021: 105277


    Reducing meat consumption may improve human health, curb environmental damage, and limit the large-scale suffering of animals reared in factory farms. Most attention to reducing consumption has focused on restructuring environments where foods are chosen or on making health or environmental appeals. However, psychological theory suggests that interventions appealing to animal welfare concerns might operate on distinct, potent pathways. We conducted a systematic review and meta-analysis evaluating the effec-tiveness of these interventions. We searched eight academic databases and extensively searched grey literature. We meta-analyzed 100 studies assessing interventions designed to reduce meat consumption or purchase by mentioning or portraying farm animals, that measured behavioral or self-reported outcomes related to meat consumption, purchase, or related intentions, and that had a control condition. The interventions consistently reduced meat consumption, purchase, or related intentions at least in the short term with meaningfully large effects (meta-analytic mean risk ratio [RR] = 1.22; 95% CI: [1.13, 1.33]). We estimated that a large majority of true population effects (71%; 95% CI: [59%, 80%]) were stronger than RR = 1.1 and that few were in the unintended direction. Via meta-regression, we identified some specific characteristics of studies and interventions that were associated with effect size. Risk-of-bias assessments identified both methodological strengths and limitations of this literature; however, results did not differ meaningfully in sensitivity analyses retaining only studies at the lowest risk of bias. Evidence of publication bias was not apparent. In conclusion, animal welfare inter-ventions preliminarily appear effective in these typically short-term studies of primarily self-reported outcomes. Future research should use direct behavioral outcomes that mini-mize the potential for social desirability bias and are measured over long-term follow-up.

    View details for DOI 10.1016/j.appet.2021.105277

    View details for PubMedID 33984401

  • Therapeutic Implications of Diet in Inflammatory Bowel Disease and Related Immune-Mediated Inflammatory Diseases. Nutrients Jiang, Y., Jarr, K., Layton, C., Gardner, C. D., Ashouri, J. F., Abreu, M. T., Sinha, S. R. 2021; 13 (3)


    Despite being a focal issue to patients, the effect of diet on adult inflammatory bowel disease (IBD) remains underexplored with limited guidance. While promising clinical trials are currently underway, there is a need for further evidence-based recommendations. As such, we summarize the current evidence on various diets used in the treatment of IBD and also explore the potential applications of dietary data from related immune-mediated inflammatory diseases (IMIDs), such as rheumatoid arthritis and psoriasis, to provide additional information to inform IBD providers. To date, there have been multiple diets investigated as adjunctive therapy in IBD, but many associated studies are small, non-randomized, and not controlled. Mediterranean, vegetarian/vegan, and reduced-calorie/fasting diets have been studied and have shown some positive results in other IMIDs, which may suggest potential applicability to those with IBD, but larger, well-designed clinical trials are needed for further guidance. Gluten-free and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP)diets do not appear to have an impact on IBD disease activity, but low FODMAP may potentially be helpful for those with concurrent functional gastrointestinal symptoms. Specific carbohydrate diets have been mainly assessed in children but show some potential in small adult studies.

    View details for DOI 10.3390/nu13030890

    View details for PubMedID 33801883

  • "Instead of what," and repeated 4-year interval change regarding red meat and T2D: increasing causal inference in nutritional epidemiology through methodological advances. The American journal of clinical nutrition Gardner, C. 2021

    View details for DOI 10.1093/ajcn/nqaa385

    View details for PubMedID 33515020

  • Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals. Nature medicine Asnicar, F., Berry, S. E., Valdes, A. M., Nguyen, L. H., Piccinno, G., Drew, D. A., Leeming, E., Gibson, R., Le Roy, C., Khatib, H. A., Francis, L., Mazidi, M., Mompeo, O., Valles-Colomer, M., Tett, A., Beghini, F., Dubois, L., Bazzani, D., Thomas, A. M., Mirzayi, C., Khleborodova, A., Oh, S., Hine, R., Bonnett, C., Capdevila, J., Danzanvilliers, S., Giordano, F., Geistlinger, L., Waldron, L., Davies, R., Hadjigeorgiou, G., Wolf, J., Ordovas, J. M., Gardner, C., Franks, P. W., Chan, A. T., Huttenhower, C., Spector, T. D., Segata, N. 2021


    The gut microbiome is shaped by diet and influences host metabolism; however, these links are complex and can be unique to each individual. We performed deep metagenomic sequencing of 1,203 gut microbiomes from 1,098 individuals enrolled in the Personalised Responses to Dietary Composition Trial (PREDICT 1) study, whose detailed long-term diet information, as well as hundreds of fasting and same-meal postprandial cardiometabolic blood marker measurements were available. We found many significant associations between microbes and specific nutrients, foods, food groups and general dietary indices, which were driven especially by the presence and diversity of healthy and plant-based foods. Microbial biomarkers of obesity were reproducible across external publicly available cohorts and in agreement with circulating blood metabolites that are indicators of cardiovascular disease risk. While some microbes, such as Prevotella copri and Blastocystis spp., were indicators of favorable postprandial glucose metabolism, overall microbiome composition was predictive for a large panel of cardiometabolic blood markers including fasting and postprandial glycemic, lipemic and inflammatory indices. The panel of intestinal species associated with healthy dietary habits overlapped with those associated with favorable cardiometabolic and postprandial markers, indicating that our large-scale resource can potentially stratify the gut microbiome into generalizable health levels in individuals without clinically manifest disease.

    View details for DOI 10.1038/s41591-020-01183-8

    View details for PubMedID 33432175

  • Adherence to Ketogenic and Mediterranean Study Diets in a Crossover Trial: The Keto-Med Randomized Trial. Nutrients Landry, M. J., Crimarco, A. n., Perelman, D. n., Durand, L. R., Petlura, C. n., Aronica, L. n., Robinson, J. L., Kim, S. H., Gardner, C. D. 2021; 13 (3)


    Adherence is a critical factor to consider when interpreting study results from randomized clinical trials (RCTs) comparing one diet to another, but it is frequently not reported by researchers. The purpose of this secondary analysis of the Keto-Med randomized trial was to provide a detailed examination and comparison of the adherence to the two study diets (Well Formulated Ketogenic Diet (WFKD) and Mediterranean Plus (Med-Plus)) under the two conditions: all food being provided (delivered) and all food being obtained by individual participants (self-provided). Diet was assessed at six time points including baseline (×1), week 4 of each phase when participants were receiving food deliveries (×2), week 12 of each phase when participants were preparing and providing food on their own (×2), and 12 weeks after participants completed both diet phases and were free to choose their own diet pattern (×1). The adherence scores for WFKD and Med-Plus were developed specifically for this study. Average adherence to the two diet patterns was very similar during both on-study time points of the intervention. Throughout the study, a wide range of adherence was observed among participants-for both diet types and during both the delivery phase and self-provided phase. Insight from this assessment of adherence may aid other researchers when answering the important question of how to improve behavioral adherence during dietary trials. This study is registered at NCT03810378.

    View details for DOI 10.3390/nu13030967

    View details for PubMedID 33802709

  • Isthmin-1 is an adipokine that promotes glucose uptake and improves glucose tolerance and hepatic steatosis. Cell metabolism Jiang, Z., Zhao, M., Voilquin, L., Jung, Y., Aikio, M. A., Sahai, T., Dou, F. Y., Roche, A. M., Carcamo-Orive, I., Knowles, J. W., Wabitsch, M., Appel, E. A., Maikawa, C. L., Camporez, J. P., Shulman, G. I., Tsai, L., Rosen, E. D., Gardner, C. D., Spiegelman, B. M., Svensson, K. J. 2021


    With the increasing prevalence of type 2 diabetes and fatty liver disease, there is still an unmet need to better treat hyperglycemia and hyperlipidemia. Here, we identify isthmin-1 (Ism1) as an adipokine and one that has a dual role in increasing adipose glucose uptake while suppressing hepatic lipid synthesis. Ism1 ablation results in impaired glucose tolerance, reduced adipose glucose uptake, and reduced insulin sensitivity, demonstrating an endogenous function for Ism1 in glucose regulation. Mechanistically, Ism1 activates a PI3K-AKT signaling pathway independently of the insulin and insulin-like growth factor receptors. Notably, while the glucoregulatory function is shared with insulin, Ism1 counteracts lipid accumulation in the liver by switching hepatocytes from a lipogenic to a protein synthesis state. Furthermore, therapeutic dosing of recombinant Ism1 improves diabetes in diet-induced obese mice and ameliorates hepatic steatosis in a diet-induced fatty liver mouse model. These findings uncover an unexpected, bioactive protein hormone that might have simultaneous therapeutic potential for diabetes and fatty liver disease.

    View details for DOI 10.1016/j.cmet.2021.07.010

    View details for PubMedID 34348115

  • Examining differences between overweight women and men in 12-month weight loss study comparing healthy low-carbohydrate vs. low-fat diets. International journal of obesity (2005) Aronica, L., Rigdon, J., Offringa, L. C., Stefanick, M. L., Gardner, C. D. 2020


    BACKGROUND/OBJECTIVES: Biological sex factors and sociocultural gender norms affect the physiology and behavior of weight loss. However, most diet intervention studies do not report outcomes by sex, thereby impeding reproducibility. The objectives of this study were to compare 12-month changes in body weight and composition in groups defined by diet and sex, and adherence to a healthy low carbohydrate (HLC) vs. healthy low fat (HLF) diet.PARTICIPANTS/METHODS: This was a secondary analysis of the DIETFITS trial, in which 609 overweight/obese nondiabetic participants (age, 18-50 years) were randomized to a 12-month HLC (n=304) or HLF (n=305) diet. Our first aim concerned comparisons in 12-month changes in weight, fat mass, and lean mass by group with appropriate adjustment for potential confounders. The second aim was to assess whether or not adherence differed by diet-sex group (HLC women n=179, HLC men n=125, HLF women n=167, HLF men n=138).RESULTS: 12-month changes in weight (p<0.001) were different by group. HLC produced significantly greater weight loss, as well as greater loss of both fat mass and lean mass, than HLF among men [-2.98kg (-4.47, -1.50); P<0.001], but not among women. Men were more adherent to HLC than women (p=0.02). Weight loss estimates within group remained similar after adjusting for adherence, suggesting adherence was not a mediator.CONCLUSIONS: By reporting outcomes by sex significant weight loss differences were identified between HLC and HLF, which were not recognized in the original primary analysis. These findings highlight the need to consider sex in the design, analysis, and reporting of diet trials.

    View details for DOI 10.1038/s41366-020-00708-y

    View details for PubMedID 33188301

  • Nutrition Study Design Issues-Important Issues for Interpretation. American journal of health promotion : AJHP Gardner, C. D., Crimarco, A., Landry, M. J., Fielding-Singh, P. 2020; 34 (8): 951–54

    View details for DOI 10.1177/0890117120960580d

    View details for PubMedID 33076690

  • Impact of a Scalable, Multi-Campus "Foodprint" Seminar on College Students' Dietary Intake and Dietary Carbon Footprint. Nutrients Malan, H., Amsler Challamel, G., Silverstein, D., Hoffs, C., Spang, E., Pace, S. A., Malagueno, B. L., Gardner, C. D., Wang, M. C., Slusser, W., Jay, J. A. 2020; 12 (9)


    BACKGROUND: Dietary patterns affect both human health and environmental sustainability. Prior research found a ten-unit course on food systems and environmental sustainability shifted dietary intake and reduced dietary carbon footprint among college students. This research evaluated the impact of a similar, more scalable one-unit Foodprint seminar taught at multiple universities.METHODS: We used a quasi-experimental pre-post nonequivalent comparison group design (n = 176). As part of the Menus of Change University Research Collaborative, research was conducted at three university campuses in California over four academic terms. All campuses used the same curriculum, which incorporates academic readings, group discussions, and skills-based exercises to evaluate the environmental footprint of different foods. The comparison group comprised students taking unrelated one-unit courses at the same universities. A questionnaire was administered at the beginning and end of each term.RESULTS: Students who took the Foodprint seminar significantly improved their reported vegetable intake by 4.7 weekly servings relative to the comparison group. They also reported significantly decreasing intake of ruminant meat and sugar-sweetened beverages. As a result of dietary shifts, Foodprint seminar students were estimated to have significantly decreased their dietary carbon footprint by 14%.CONCLUSIONS: A scalable, one-unit Foodprint seminar may simultaneously promote environmental sustainability and human health.

    View details for DOI 10.3390/nu12092890

    View details for PubMedID 32971829

  • Heterogeneity in the Effects of Food Vouchers on Nutrition Among Low-Income Adults: A Quantile Regression Analysis. American journal of health promotion : AJHP White, J. S., Vasconcelos, G., Harding, M., Carroll, M. M., Gardner, C. D., Basu, S., Seligman, H. K. 2020: 890117120952991


    PURPOSE: To determine whether baseline fruit and vegetable (FV) intake or other predictors are associated with response to food vouchers (change in FV intake) among low-income adults.DESIGN: Secondary analysis of a randomized, 2 x 2-factorial, community-based trial.SETTING: San Francisco, California.SUBJECTS: 359 low-income adults aged ≥21 years old.INTERVENTION: Participants were mailed $20 of food vouchers monthly for 6 months, and randomized to 1 of 4 arms according to: eligible foods (FV only or any foods) and redemption schedule (weekly or monthly).MEASURES: Change in FV intake measured in cup equivalents between baseline and month 6 of the trial, based on 24-hour dietary recalls.ANALYSIS: Quantile multivariate regressions were employed to measure associations between key predictors and change in FV intake across study arms.RESULTS: FV-only weekly vouchers were associated with increased FV intake at the 25th percentile (0.24 cups/day, p = 0.048) and 50th percentile (0.37 cups/day, p = 0.02) of the distribution, but not at lower and higher quantiles. Response to the vouchers diminished 0.10 cups/day for each additional household member (p = 0.02).CONCLUSION: Response to food vouchers varied along the FV intake distribution, pointing to some more responsive groups and others potentially needing additional support to increase FV intake. Larger households likely need vouchers of higher dollar value to result in similar changes in dietary intake as that observed in smaller households.

    View details for DOI 10.1177/0890117120952991

    View details for PubMedID 32878448

  • Faith in Fat: A Multisite Examination of University Students' Perceptions of Fat in the Diet. Nutrients Landry, M. J., Olvany, J. M., Mueller, M. P., Chen, T., Ikeda, D., Sinclair, D., Schatz, L. E., Connors, P., Valgenti, R. T., Amsler Challamel, G., Gardner, C. D., Policastro, P. 2020; 12 (9)


    Despite recent relaxation of restrictions on dietary fat consumption in dietary guidelines, there remains a collective "fear of fat". This study examined college students' perceptions of health among foods with no fat relative to foods with different types of fats (unsaturated and saturated). Utilizing a multisite approach, this study collected data from college students at six university dining halls throughout the United States. Data were available on 533 students. Participants were 52% male and consisted largely of first-year students (43%). Across three meal types, the no-fat preparation option was chosen 73% of the time, the unsaturated fat option was selected 23% of the time, and the saturated fat option was chosen 4% of the time. Students chose the no-fat option for all meal types 44% of the time. Findings suggest that college students lack knowledge regarding the vital role played by the type and amount of fats within a healthy diet. Nutrition education and food system reforms are needed to help consumers understand that type of fat is more important than total amount of fat. Efforts across various sectors can encourage incorporating, rather than avoiding, fats within healthy dietary patterns.

    View details for DOI 10.3390/nu12092560

    View details for PubMedID 32846997

  • The First, Comprehensive, Open-Source Culinary Medicine Curriculum for Health Professional Training Programs: A Global Reach. American journal of lifestyle medicine Hauser, M. E., Nordgren, J. R., Adam, M., Gardner, C. D., Rydel, T., Bever, A. M., Steinberg, E. 2020; 14 (4): 369-373


    Providing a strong foundation in culinary medicine (CM)-including what constitutes a healthy diet and how to find, obtain, and prepare healthy and delicious food-is a cornerstone of educating health professionals to support patients in achieving better health outcomes. The Culinary Medicine Curriculum (CMC), published in collaboration with the American College of Lifestyle Medicine, is the first, comprehensive, open-source guide created to support the implementation of CM at health professional training programs (HPTPs) worldwide. The CMC is modeled after the successful CM elective course for Stanford University School of Medicine students. Key goals of the CMC include presenting healthy food as unapologetically delicious, quick, and inexpensive; translating lessons learned to healthy eating on-the-go; practicing motivational interviewing on healthy dietary behavior changes; and demonstrating how to launch a CM course. The CMC highlights a predominantly whole food, plant-based diet as seen through the lenses of different world flavors and culinary traditions. It was developed, published, and distributed with the aim of expanding CM by reducing barriers to creating CM courses within most types of HPTPs and practice settings. During the first 2 months the CMC was available, it was downloaded 2379 times in 83 countries by a wide variety of health care professionals interested in teaching CM. The global interest in this first, freely available, evidence-based CMC underscores the demand for CM resources. Such resources could prove foundational in expediting development of CM courses and expanding the reach of CM and counseling on dietary behavior changes into patient care.

    View details for DOI 10.1177/1559827620916699

    View details for PubMedID 33281516

    View details for PubMedCentralID PMC7692007

  • The First, Comprehensive, Open-Source Culinary Medicine Curriculum for Health Professional Training Programs: A Global Reach AMERICAN JOURNAL OF LIFESTYLE MEDICINE Hauser, M. E., Nordgren, J. R., Adam, M., Gardner, C. D., Rydel, T., Bever, A. M., Steinberg, E. 2020; 14 (4): 369–73
  • Author Correction: Gut microbiota plasticity is correlated with sustained weight loss on a low-carb or low-fat dietary intervention. Scientific reports Grembi, J. A., Nguyen, L. H., Haggerty, T. D., Gardner, C. D., Holmes, S. P., Parsonnet, J. 2020; 10 (1): 11095


    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

    View details for DOI 10.1038/s41598-020-68280-z

    View details for PubMedID 32606436

  • High-Throughput Stool Metaproteomics: Method and Application to Human Specimens. mSystems Gonzalez, C. G., Wastyk, H. C., Topf, M., Gardner, C. D., Sonnenburg, J. L., Elias, J. E. 2020; 5 (3)


    Stool-based proteomics is capable of significantly augmenting our understanding of host-gut microbe interactions. However, compared to competing technologies, such as metagenomics and 16S rRNA sequencing, it is underutilized due to its low throughput and the negative impact sample contaminants can have on highly sensitive mass spectrometry equipment. Here, we present a new stool proteomic processing pipeline that addresses these shortcomings in a highly reproducible and quantitative manner. Using this method, 290 samples from a dietary intervention study were processed in approximately 1.5weeks, largely done by a single researcher. These data indicated a subtle but distinct monotonic increase in the number of significantly altered proteins between study participants on fiber- or fermented food-enriched diets. Lastly, we were able to classify study participants based on their diet-altered proteomic profiles and demonstrated that classification accuracies of up to 89% could be achieved by increasing the number of subjects considered. Taken together, this study represents the first high-throughput proteomic method for processing stool samples in a technically reproducible manner and has the potential to elevate stool-based proteomics as an essential tool for profiling host-gut microbiome interactions in a clinical setting.IMPORTANCE Widely available technologies based on DNA sequencing have been used to describe the kinds of microbes that might correlate with health and disease. However, mechanistic insights might be best achieved through careful study of the dynamic proteins at the interface between the foods we eat, our microbes, and ourselves. Mass spectrometry-based proteomics has the potential to revolutionize our understanding of this complex system, but its application to clinical studies has been hampered by low-throughput and laborious experimentation pipelines. In response, we developed SHT-Pro, the first high-throughput pipeline designed to rapidly handle large stool sample sets. With it, a single researcher can process over one hundred stool samples per week for mass spectrometry analysis, conservatively approximately 10* to 100* faster than previous methods, depending on whether isobaric labeling is used or not. Since SHT-Pro is fairly simple to implement using commercially available reagents, it should be easily adaptable to large-scale clinical studies.

    View details for DOI 10.1128/mSystems.00200-20

    View details for PubMedID 32606025

  • Human postprandial responses to food and potential for precision nutrition. Nature medicine Berry, S. E., Valdes, A. M., Drew, D. A., Asnicar, F., Mazidi, M., Wolf, J., Capdevila, J., Hadjigeorgiou, G., Davies, R., Al Khatib, H., Bonnett, C., Ganesh, S., Bakker, E., Hart, D., Mangino, M., Merino, J., Linenberg, I., Wyatt, P., Ordovas, J. M., Gardner, C. D., Delahanty, L. M., Chan, A. T., Segata, N., Franks, P. W., Spector, T. D. 2020


    Metabolic responses to food influence risk of cardiometabolic disease, but large-scale high-resolution studies are lacking. We recruited n=1,002 twins and unrelated healthy adults in the United Kingdom to the PREDICT 1 study and assessed postprandial metabolic responses in a clinical setting and at home. We observed large inter-individual variability (as measured by the population coefficient of variation (s.d./mean, %)) in postprandial responses of blood triglyceride (103%), glucose (68%) and insulin (59%) following identical meals. Person-specific factors, such as gut microbiome, had a greater influence (7.1% of variance) than did meal macronutrients (3.6%) for postprandial lipemia, but not for postprandial glycemia (6.0% and 15.4%, respectively); genetic variants had a modest impact on predictions (9.5% for glucose, 0.8% for triglyceride, 0.2% for C-peptide). Findings were independently validated in a US cohort (n=100 people). We developed a machine-learning model that predicted both triglyceride (r=0.47) and glycemic (r=0.77) responses to food intake. These findings may be informative for developing personalized diet strategies. The registration identifier is NCT03479866.

    View details for DOI 10.1038/s41591-020-0934-0

    View details for PubMedID 32528151

  • The WELL diet score correlates with the alternative healthy eating index-2010. Food science & nutrition Springfield, S., Cunanan, K., Heaney, C., Peng, K., Gardner, C. 2020; 8 (6): 2710-2718


    The quality of one's overall diet has proven to be of great importance to health and well-being. Unfortunately, diet quality is time-consuming to assess. The Stanford Wellness Living Laboratory (WELL) administered an online survey that included the WELL Diet Score (a novel diet quality assessment calculated from 12 diet-related items). Subsequently, WELL participants were asked to complete the 127-item Block Food Frequency Questionnaire (FFQ) online. The present study's primary objective was to compare the WELL Diet Score with the established FFQ-based Alternative Healthy Eating Index-2010 (AHEI-2010), in a subset of WELL participants (n = 248) who completed both dietary measures through WELL's online platform. The two scores were significantly correlated (r = .69; p < .0001). Regression analyses demonstrated that the WELL Diet Score was positively significantly associated with sociodemographic determinants of diet quality and protective health factors, including older age, higher education, lower BMI, and higher physical activity. In summary, the WELL Diet Score, derived from 12 small diet-related items that can be completed in 5 min, was significantly positively correlated with the AHEI-2010 derived from the lengthy 127-item FFQ, suggesting the potential utility of the WELL Diet Score in future large-scale studies, including future WELL studies.

    View details for DOI 10.1002/fsn3.1558

    View details for PubMedID 32566188

    View details for PubMedCentralID PMC7300046

  • Proteomic profiles before and during weight loss: Results from randomized trial of dietary intervention. Scientific reports Figarska, S. M., Rigdon, J., Ganna, A., Elmstahl, S., Lind, L., Gardner, C. D., Ingelsson, E. 2020; 10 (1): 7913


    Inflammatory and cardiovascular biomarkers have been associated with obesity, but little is known about how they change upon dietary intervention and concomitant weight loss. Further, protein biomarkers might be useful for predicting weight loss in overweight and obese individuals. We performed secondary analyses in the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) randomized intervention trial that included healthy 609 adults (18-50 years old) with BMI 28-40kg/m2, to evaluate associations between circulating protein biomarkers and BMI at baseline, during a weight loss diet intervention, and to assess predictive potential of baseline blood proteins on weight loss. We analyzed 263 plasma proteins at baseline and 6 months into the intervention using the Olink Proteomics CVD II, CVD III and Inflammation arrays. BMI was assessed at baseline, after 3 and 6 months of dietary intervention. At baseline, 102 of the examined inflammatory and cardiovascular biomarkers were associated with BMI (>90% with successful replication in 1,584 overweight/obese individuals from a community-based cohort study) and 130 tracked with weight loss shedding light into the pathophysiology of obesity. However, out of 263 proteins analyzed at baseline, only fibroblast growth factor 21 (FGF-21) predicted weight loss, and none helped individualize dietary assignment.

    View details for DOI 10.1038/s41598-020-64636-7

    View details for PubMedID 32404980

  • The WELL diet score correlates with the alternative healthy eating index-2010 FOOD SCIENCE & NUTRITION Springfield, S., Cunanan, K., Heaney, C., Peng, K., Gardner, C. 2020

    View details for DOI 10.1002/fsn3.1558

    View details for Web of Science ID 000530379700001

  • The COronavirus Pandemic Epidemiology (COPE) Consortium: A Call to Action. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology Chan, A. T., Drew, D. A., Nguyen, L. H., Joshi, A. D., Ma, W., Guo, C., Lo, C., Mehta, R. S., Kwon, S., Sikavi, D. R., Magicheva-Gupta, M. V., Fatehi, Z. S., Flynn, J. J., Leonardo, B. M., Albert, C. M., Andreotti, G., Beane Freeman, L. E., Balasubramanian, B. A., Brownstein, J. S., Bruinsma, F., Cowan, A. N., Deka, A., Ernst, M. E., Figueiredo, J. C., Franks, P. W., Gardner, C. D., Ghobrial, I. M., Haiman, C. A., Hall, J. E., Deming-Halverson, S. L., Kirpach, B., Lacey, J. V., Le Marchand, L., Marinac, C. R., Martinez, M. E., Milne, R. L., Murray, A. M., Nash, D., Palmer, J. R., Patel, A. V., Rosenberg, L., Sandler, D. P., Sharma, S. V., Schurman, S. H., Wilkens, L. R., Chavarro, J. E., Eliassen, A. H., Hart, J. E., Kang, J. H., Koenen, K. C., Kubzansky, L. D., Mucci, L. A., Ourselin, S., Rich-Edwards, J. W., Song, M., Stampfer, M. J., Steves, C. J., Willett, W. C., Wolf, J., Spector, T. 2020


    The rapid pace of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (COVID-19) pandemic presents challenges to the real-time collection of population-scale data to inform near-term public health needs as well as future investigations. We established the COronavirus Pandemic Epidemiology (COPE) consortium to address this unprecedented crisis on behalf of the epidemiology research community. As a central component of this initiative, we have developed a COVID-19 Symptom Tracker mobile application as a common data collection tool for epidemiologic cohort studies with active study participants. This mobile application collects information on risk factors, daily symptoms, and outcomes through a user-friendly interface that minimizes participant burden. Combined with our efforts within the general population, data collected from nearly 3 million participants in the United States and United Kingdom are being used to address critical needs in the emergency response, including identifying potential hotspots of disease and clinically actionable risk factors. The linkage of symptom data collected in the app with information and biospecimens already collected in epidemiology cohorts will position us to address key questions related to diet, lifestyle, environmental and socioeconomic factors on susceptibility to COVID-19, clinical outcomes related to infection, and long-term physical, mental health, and financial sequalae. We call upon additional epidemiology cohorts to join this collective effort to strengthen our impact on the current health crisis and generate a new model for a collaborative and nimble research infrastructure that will lead to more rapid translation of our work for the betterment of public health.

    View details for DOI 10.1158/1055-9965.EPI-20-0606

    View details for PubMedID 32371551

  • Reply to JG Dorea. Advances in nutrition (Bethesda, Md.) Katz, D. L., Gardner, C. D. 2020; 11 (3): 740

    View details for DOI 10.1093/advances/nmaa002

    View details for PubMedID 32419020

  • Protein and amino acids adequacy in vegetarian diets CAHIERS DE NUTRITION ET DE DIETETIQUE Mariotti, F., Gardner, C. D. 2020; 55 (2): 66–81
  • Long-term dietary intervention reveals resilience of the gut microbiota despite changes in diet and weight. The American journal of clinical nutrition Fragiadakis, G. K., Wastyk, H. C., Robinson, J. L., Sonnenburg, E. D., Sonnenburg, J. L., Gardner, C. D. 2020


    BACKGROUND: With the rising rates of obesity and associated metabolic disorders, there is a growing need for effective long-term weight-loss strategies, coupled with an understanding of how they interface with human physiology. Interest is growing in the potential role of gut microbes as they pertain to responses to different weight-loss diets; however, the ways that diet, the gut microbiota, and long-term weight loss influence one another is not well understood.OBJECTIVES: Our primary objective was to determine if baseline microbiota composition or diversity was associated with weight-loss success. A secondary objective was to track the longitudinal associations of changes to lower-carbohydrate or lower-fat diets and concomitant weight loss with the composition and diversity of the gut microbiota.METHODS: We used 16S ribosomal RNA gene amplicon sequencing to profile microbiota composition over a 12-mo period in 49 participants as part of a larger randomized dietary intervention study of participants consuming either a healthy low-carbohydrate or a healthy low-fat diet.RESULTS: While baseline microbiota composition was not predictive of weight loss, each diet resulted in substantial changes in the microbiota 3-mo after the start of the intervention; some of these changes were diet specific (14 taxonomic changes specific to the healthy low-carbohydrate diet, 12 taxonomic changes specific to the healthy low-fat diet) and others tracked with weight loss (7 taxonomic changes in both diets). After these initial shifts, the microbiota returned near its original baseline state for the remainder of the intervention, despite participants maintaining their diet and weight loss for the entire study.CONCLUSIONS: These results suggest a resilience to perturbation of the microbiota's starting profile. When considering the established contribution of obesity-associated microbiotas to weight gain in animal models, microbiota resilience may need to be overcome for long-term alterations to human physiology. This trial was registered at as NCT01826591.

    View details for DOI 10.1093/ajcn/nqaa046

    View details for PubMedID 32186326

  • Diet Quality And Resilience: Examining Age Differences In A Cross-sectional Analysis Of The Well For Life Study Springfield, S., Cunanan, K., Peng, K., Gardner, C. D. LIPPINCOTT WILLIAMS & WILKINS. 2020
  • Reducing meat consumption by appealing to animal welfare: protocol for a meta-analysis and theoretical review. Systematic reviews Mathur, M. B., Robinson, T. N., Reichling, D. B., Gardner, C. D., Nadler, J., Bain, P. A., Peacock, J. 2020; 9 (1): 3


    BACKGROUND: Reducing meat consumption may improve human health, curb environmental damage and greenhouse gas emissions, and limit the large-scale suffering of animals raised in factory farms. Previous work has begun to develop interventions to reduce individual meat consumption, often by appealing directly to individual health motivations. However, research on nutritional behavior change suggests that interventions additionally linking behavior to ethical values, identity formation, and existing social movements may be particularly effective and longer-lasting. Regarding meat consumption, preliminary evidence and psychological theory suggest that appeals related to animal welfare may have considerable potential to effectively leverage these elements of human psychology. We aim to conduct a systematic review and quantitative meta-analysis evaluating the effectiveness of animal welfare-related appeals on actual or intended meat consumption or purchasing. Our investigation will critically synthesize the current state of knowledge regarding psychological mechanisms of intervening on individual meat consumption and empirically identify the psychological characteristics underlying the most effective animal welfare-based interventions.METHODS: We will systematically search eight academic databases and extensively search unpublished grey literature. We will include studies that assess interventions intended to reduce meat consumption or purchase through the mention or portrayal of animal welfare, that measure outcomes related to meat consumption or purchase, and that have a control condition. Eligible studies may recruit from any human population, be written in any language, and be published or released any time. We will meta-analyze the studies, reporting the pooled point estimate and additional metrics that describe the distribution of potentially heterogeneous effects. We will assess studies' risk of bias and conduct sensitivity analyses for publication bias. We describe possible follow-up analyses to investigate hypothesized moderators of intervention effectiveness.DISCUSSION: The findings of the proposed systematic review and meta-analysis, including any identified methodological limitations of the existing literature, could inform the design of successful evidence-based interventions with broad potential to improve human, animal, and environmental well-being.SYSTEMATIC REVIEW REGISTRATION: The protocol was preregistered via the Open Science Framework (

    View details for DOI 10.1186/s13643-019-1264-5

    View details for PubMedID 31907028

  • Gut microbiota plasticity is correlated with sustained weight loss on a low-carb or low-fat dietary intervention Scientific Reports Grembi, J. A., Nguyen, L. H., Haggerty, T. D., Gardner, C. D., Holmes, S. P., Parsonnet, J. 2020; 10
  • Challenges and opportunities for better nutrition science-an essay by Tim Spector and Christopher Gardner. BMJ (Clinical research ed.) Spector, T. D., Gardner, C. D. 2020; 369: m2470

    View details for DOI 10.1136/bmj.m2470

    View details for PubMedID 32591334

  • Dietary Protein and Amino Acids in Vegetarian Diets-A Review. Nutrients Mariotti, F., Gardner, C. D. 2019; 11 (11)


    While animal products are rich in protein, the adequacy of dietary protein intake from vegetarian/vegan diets has long been controversial. In this review, we examine the protein and amino acid intakes from vegetarian diets followed by adults in western countries and gather information in terms of adequacy for protein and amino acids requirements, using indirect and direct data to estimate nutritional status. We point out that protein-rich foods, such as traditional legumes, nuts and seeds, are sufficient to achieve full protein adequacy in adults consuming vegetarian/vegan diets, while the question of any amino acid deficiency has been substantially overstated. Our review addresses the adequacy in changes to protein patterns in people newly transitioning to vegetarian diets. We also specifically address this in older adults, where the issues linked to the protein adequacy of vegetarian diets are more complex. This contrasts with the situation in children where there are no specific concerns regarding protein adequacy because of their very high energy requirements compared to those of protein. Given the growing shifts in recommendations from nutrition health professionals for people to transition to more plant-based, whole-food diets, additional scientific evidence-based communications confirming the protein adequacy of vegetarian and vegan diets is warranted.

    View details for DOI 10.3390/nu11112661

    View details for PubMedID 31690027

  • Bacon rashers, statistics, and controversy. BMJ (Clinical research ed.) Spector, T., Gardner, C. 2019; 367: l5989

    View details for DOI 10.1136/bmj.l5989

    View details for PubMedID 31611196

  • Perspective: The Public Health Case for Modernizing the Definition of Protein Quality ADVANCES IN NUTRITION Katz, D. L., Doughty, K. N., Geagan, K., Jenkins, D. A., Gardner, C. D. 2019; 10 (5): 755–64
  • Predicting the effects of supplemental EPA and DHA on the omega-3 index. The American journal of clinical nutrition Walker, R. E., Jackson, K. H., Tintle, N. L., Shearer, G. C., Bernasconi, A., Masson, S., Latini, R., Heydari, B., Kwong, R. Y., Flock, M., Kris-Etherton, P. M., Hedengran, A., Carney, R. M., Skulas-Ray, A., Gidding, S. S., Dewell, A., Gardner, C. D., Grenon, S. M., Sarter, B., Newman, J. W., Pedersen, T. L., Larson, M. K., Harris, W. S. 2019


    BACKGROUND: Supplemental long-chain omega-3 (n-3) fatty acids (EPA and DHA) raise erythrocyte EPA+DHA [omega-3 index (O3I)] concentrations, but the magnitude or variability of this effect is unclear.OBJECTIVE: The purpose of this study was to model the effects of supplemental EPA+DHA on the O3I.METHODS: Deidentified data from 1422 individuals from 14 published n-3 intervention trials were included. Variables considered included dose, baseline O3I, sex, age, weight, height, chemical form [ethyl ester (EE) compared with triglyceride (TG)], and duration of treatment. The O3I was measured by the same method in all included studies. Variables were selected by stepwise regression using the Bayesian information criterion.RESULTS: Individuals supplemented with EPA+DHA (n=846) took a mean±SD of 1983±1297 mg/d, and the placebo controls (n=576) took none. The mean duration of supplementation was 13.6±6.0 wk. The O3I increased from 4.9%±1.7% to 8.1%±2.7% in the supplemented individuals ( P<0.0001). The final model included dose, baseline O3I, and chemical formulation type (EE or TG), and these explained 62% of the variance in response (P<0.0001). The model predicted that the final O3I (and 95% CI) for a population like this, with a baseline concentration of 4.9%, given 850 mg/d of EPA+DHA EE would be 6.5% (95% CI: 6.3%, 6.7%). Gram for gram, TG-based supplements increased the O3I by about 1 percentage point more than EE products.CONCLUSIONS: Of the factors tested, only baseline O3I, dose, and chemical formulation were significant predictors of O3I response to supplementation. The model developed here can be used by researchers to help estimate the O3I response to a given EPA+DHA dose and chemical form.

    View details for DOI 10.1093/ajcn/nqz161

    View details for PubMedID 31396625

  • Preventing weight gain more important than weight loss and more realistic to study in cohorts than in randomized controlled trials. The American journal of clinical nutrition Gardner, C. D. 2019

    View details for DOI 10.1093/ajcn/nqz101

    View details for PubMedID 31127808

  • To Text or Not to Text: Electronic Message Intervention to Improve Treatment Adherence Versus Matched Historical Controls JMIR MHEALTH AND UHEALTH Oppezzo, M. A., Stanton, M., Garcia, A., Rigdon, J., Berman, J. R., Gardner, C. D. 2019; 7 (4)

    View details for DOI 10.2196/11720

    View details for Web of Science ID 000465340100001

  • Effects Of Alternative Food Voucher Delivery Strategies On Nutrition Among Low-Income Adults HEALTH AFFAIRS Basu, S., Gardner, C. D., White, J. S., Rigdon, J., Carroll, M. M., Akers, M., Seligman, H. K. 2019; 38 (4): 577–84
  • Objective versus Self-Reported Energy Intake Changes During Low-Carbohydrate and Low-Fat Diets OBESITY Guo, J., Robinson, J. L., Gardner, C. D., Hall, K. D. 2019; 27 (3): 420–26

    View details for DOI 10.1002/oby.22389

    View details for Web of Science ID 000459626000010

  • Changes in blood lipid concentrations associated with changes in intake of dietary saturated fat in the context of a healthy low-carbohydrate weight-loss diet: a secondary analysis of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) trial AMERICAN JOURNAL OF CLINICAL NUTRITION Shih, C. W., Hauser, M. E., Aronica, L., Rigdon, J., Gardner, C. D. 2019; 109 (2): 433–41
  • Perspective: The Public Health Case for Modernizing the Definition of Protein Quality. Advances in nutrition (Bethesda, Md.) Katz, D. L., Doughty, K. N., Geagan, K. n., Jenkins, D. A., Gardner, C. D. 2019


    Prevailing definitions of protein quality are predicated on considerations of biochemistry and metabolism rather than the net effects on human health or the environment of specific food sources of protein. In the vernacular, higher "quality" equates to desirability. This implication is compounded by sequential, societal trends in which first dietary fat and then dietary carbohydrate were vilified during recent decades, leaving dietary protein under an implied halo. The popular concept that protein is "good" and that the more the better, coupled with a protein quality definition that favors meat, fosters the impression that eating more meat, as well as eggs and dairy, is desirable and preferable. This message, however, is directly opposed to current Dietary Guidelines for Americans, which encourage consumption of more plant foods and less meat, and at odds with the literature on the environmental impacts of foods, from carbon emissions to water utilization, which decisively favor plant protein sources. Thus, the message conveyed by the current definitions of protein quality is at odds with imperatives of public and planetary health alike. We review the relevant literature in this context and make the case that the definition of protein quality is both misleading and antiquated. We propose a modernized definition that incorporates the quality of health and environmental outcomes associated with specific food sources of protein. We demonstrate how such an approach can be adapted into a metric and applied to the food supply.

    View details for PubMedID 31066877

  • Self-Reported Measures of Discretionary Salt Use Accurately Estimated Sodium Intake Overall but not in Certain Subgroups of US Adults from 3 Geographic Regions in the Salt Sources Study. The Journal of nutrition Quader, Z. S., Zhao, L. n., Harnack, L. J., Gardner, C. D., Shikany, J. M., Steffen, L. M., Gillespie, C. n., Moshfegh, A. n., Cogswell, M. E. 2019


    Excess sodium intake can increase blood pressure, and high blood pressure is a major risk factor for cardiovascular disease. Accurate population sodium intake estimates are essential for monitoring progress toward reduction, but data are limited on the amount of sodium consumed from discretionary salt.The aim of this study was to compare measured sodium intake from salt added at the table with that estimated according to the Healthy People 2020 (HP 2020) methodology.Data were analyzed from the 2014 Salt Sources Study, a cross-sectional convenience sample of 450 white, black, Asian, and Hispanic adults living in Alabama, Minnesota, and California. Sodium intake from foods and beverages was assessed for each participant through the use of 24-h dietary recalls. Estimated sodium intake from salt used at the table was assessed from self-reported frequency and estimated amounts from a previous study (HP 2020 methodology). Measured intake was assessed through the use of duplicate salt samples collected on recall days.Among all study participants, estimated and measured mean sodium intakes from salt added at the table were similar, with a nonsignificant difference of 8.9 mg/d (95% CI: -36.6, 54.4 mg/d). Among participants who were non-Hispanic Asian, Hispanic, had a bachelor's degree or higher education, lived in California or Minnesota, did not report hypertension, or had normal BMI, estimated mean sodium intake was 77-153 mg/d greater than measured intake (P < 0.05). The estimated mean sodium intake was 186-300 mg/d lower than measured intake among participants who were non-Hispanic black, had a high school degree or less, or reported hypertension (P < 0.05).The HP 2020 methodology for estimating sodium consumed from salt added at the table may be appropriate for the general US adult population; however, it underestimates intake in certain population subgroups, particularly non-Hispanic black, those with a high school degree or less, or those with self-reported hypertension. This study was registered at as NCT02474693.

    View details for DOI 10.1093/jn/nxz110

    View details for PubMedID 31179499

  • Baseline Psychosocial and Demographic Factors Associated with Study Attrition and 12‐Month Weight Gain in the DIETFITS Trial Obesity Fielding-Singh, P., Patel, M., King, A., Gardner, C. 2019

    View details for DOI 10.1002/oby.22650

  • Trade-offs in rigor and generalizability in a diet trial of glycemic control in adults with type 2 diabetes using whole foods and dietary supplements. The American journal of clinical nutrition Gardner, C. 2018

    View details for PubMedID 30084905

  • Trade-offs in rigor and generalizability in a diet trial of glycemic control in adults with type 2 diabetes using whole foods and dietary supplements AMERICAN JOURNAL OF CLINICAL NUTRITION Gardner, C. 2018; 108 (2): 205-206
  • Low-Fat vs Low-Carbohydrate Diets and Weight Loss Reply JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Gardner, C. 2018; 320 (2): 203-204
  • Antioxidants from diet or supplements do not alter inflammatory markers in adults with cardiovascular disease risk. A pilot randomized controlled trial NUTRITION RESEARCH Dewell, A., Tsao, P., Rigdon, J., Gardner, C. D. 2018; 50: 63–72


    Antioxidants have been reported to have anti-inflammatory effects, but there is a lack of research comparing food to supplement antioxidant sources. The aim of this study was to determine if increases in intake of foods naturally rich in antioxidants would lower blood levels of inflammatory markers more than consuming antioxidant supplements among adults with cardiovascular disease risk factors. Eighty-eight generally healthy adults with ≥1 elevated risk factor for cardiovascular disease were randomized in a single-blind (diets)/double-blind (supplements), parallel-group study for 8 weeks. Participants consumed (1) usual diet and placebo pills (n = 29), (2) usual diet and antioxidant supplements (n = 29), or (3) antioxidant-rich foods closely matched to antioxidant content of supplements and placebo (n = 30). Usual diet combined with antioxidant supplements or increased antioxidant-rich food intake was designed to approximately double daily habitual antioxidant intake. Antioxidant pills included carotenoids, mixed tocopherols, vitamin C, and selenium. Fasting blood samples were analyzed for inflammatory marker concentrations of interleukin-6, monocyte chemotactic protein-1, and soluble intercellular adhesion molecule-1. Participants in the intervention groups successfully doubled most antioxidants as verified by diet records and elevated blood concentrations in treatment groups. Baseline levels of inflammatory markers for the entire study group were 110 ± 65 pg/mL for monocyte chemotactic protein-1, 0.9 ± 0.7 pg/mL for interleukin-6, and 217 ± 56 ng/mL for soluble intercellular adhesion molecule-1 (means ± standard deviation) and did not differ by treatment arm. After 8 weeks, there were no significant within-group changes or between-group 8-week change differences in inflammatory marker concentrations. In conclusion, no beneficial effects were detected on the inflammatory markers investigated in response to antioxidants from foods or supplements.

    View details for PubMedID 29540273

  • Low-Fat vs Low-Carbohydrate Diets and Weight Loss-Reply. JAMA Gardner, C. 2018; 320 (2): 203–4

    View details for PubMedID 29998334

  • Fruits and Vegetables Versus Vegetables and Fruits: Rhyme and Reason for Word Order in Health Messages. American journal of lifestyle medicine Offringa, L. C., Stanton, M. V., Hauser, M. E., Gardner, C. D. 2018; 13 (3): 224–34


    Both vegetable and fruit consumption contribute to wellness and disease prevention. Most dietary health messages promote both together and position the word "fruits" before "vegetables." We examined the word order of the commonly used phrase "fruits and vegetables" through linguistics, psychology, botany, nutrition, health outcomes, and current US intake to determine if the common word order best presents these two foods in health messaging. By comparing the 10 most commonly consumed vegetables versus fruits, we found that vegetables scored higher on the Aggregate Nutrient Density Index and contained fewer calories and more fiber than fruits. Among the "nutrients of public concern" listed in the 2015 Dietary Guidelines for Americans, we determined that vegetables are better sources of these nutrients than fruits, although fruits scored higher in antioxidant content. In observational cohort studies, vegetable and fruit consumption was found to be associated with decreased mortality. Finally, daily intakes of both vegetables and fruits are lower than recommended, but the discrepancy is larger for vegetables-especially among children-suggesting a greater imperative to promote vegetables. For these reasons, future health messages promoting both together should intentionally put "vegetables" first to promote intake and emphasize their importance regarding contribution to health.

    View details for DOI 10.1177/1559827618769605

    View details for PubMedID 31105482

    View details for PubMedCentralID PMC6506980

  • Interdisciplinary food-related academic programs: A 2015 snapshot of the United States landscape. Journal of agriculture, food systems, and community development Hartle, J. C., Cole, S., Trepman, P., Chrisinger, B. W., Gardner, C. D. 2017; 7 (4): 35-50


    Interdisciplinary food-related research and study is a growing field in academia. Each year, more universities add departments, courses, majors, and minors focused on studying food and society and the complexities of growing, processing, distributing, accessing, and consuming food. In this commentary, we present our exploratory findings about interdisciplinary food-related academic programs, including food studies and food systems programs in the United States. This cross-sectional research developed a snapshot of the 2015 land-scape of interdisciplinary food-related academic programs, provided a preliminary examination of their educational offerings, and will inform future research opportunities. In this formative study, we found 82 interdisciplinary food-related under-graduate programs focused on food. Nineteen program majors, minors, or concentrations had a core disciplinary focus on sustainable agriculture. "Food studies" and "food systems" were the primary focus of 15 undergraduate programs. We found 58 interdisciplinary food-related graduate programs and extracted information on their course offerings. Organizing courses into nine course categories, 78 percent of the programs offered courses in two to five categories, and 22 percent offered courses in six to eight categories. Few courses integrated material from multiple disciplines into a single course, suggesting that these interdisciplinary programs stemmed from traditional academic silos. Based on this preliminary work, we propose to further investigate the interdisciplinary nature of food-related academic programs, map their growth trajectory, and solicit feedback from faculty and administrators about their challenges in establishing and maintaining these programs. In future research, we are also interested in exploring job options for graduates of food-related academic programs to inform recruitment strategies and courses of study.

    View details for DOI 10.5304/jafscd.2017.074.006

    View details for PubMedID 30740260

    View details for PubMedCentralID PMC6366844

  • Sources of Sodium in US Adults From 3 Geographic Regions CIRCULATION Harnack, L. J., Cogswell, M. E., Shikany, J. M., Gardner, C. D., Gillespie, C., Loria, C. M., Zhou, X., Yuan, K., Steffen, L. M. 2017; 135 (19): 1775-?


    Most US adults consume excess sodium. Knowledge about the dietary sources of sodium intake is critical to the development of effective reduction strategies.A total of 450 adults were recruited from 3 geographic locations: Birmingham, AL (n=150); Palo Alto, CA (n=150); and the Minneapolis-St. Paul, MN (n=150), metropolitan areas. Equal numbers of women and men from each of 4 race/ethnic groups (blacks, Asians, Hispanics, and non-Hispanic whites) were targeted for recruitment. Four record-assisted 24-hour dietary recalls were collected from each participant with special procedures, which included the collection of duplicate samples of salt added to food at the table and in home food preparation.Sodium added to food outside the home was the leading source of sodium, accounting for more than two thirds (70.9%) of total sodium intake in the sample. Although the proportion of sodium from this source was smaller in some subgroups, it was the leading contributor for all subgroups. Contribution ranged from 66.3% for those with a high school level of education or less to 75.0% for those 18 to 29 years of age. Sodium inherent to food was the next highest contributor (14.2%), followed by salt added in home food preparation (5.6%) and salt added to food at the table (4.9%). Home tap water consumed as a beverage and dietary supplement and nonprescription antacids contributed minimally to sodium intake (<0.5% each).Sodium added to food outside the home accounted for ≈70% of dietary sodium intake. This finding is consistent with the 2010 Institute of Medicine recommendation for reduction of sodium in commercially processed foods as the primary strategy to reduce sodium intake in the United States.URL: Unique identifier: NCT02474693.

    View details for DOI 10.1161/CIRCULATIONAHA.116.024446

    View details for Web of Science ID 000400757900008

    View details for PubMedID 28483828

  • A systematic review of studies of DNA methylation in the context of a weight loss intervention EPIGENOMICS Aronica, L., Levine, A. J., Brennan, K., Mi, J., Gardner, C., Haile, R. W., Hitchins, M. P. 2017; 9 (5): 769-787


    Obesity results from the interaction of genetic and environmental factors, which may involve epigenetic mechanisms such as DNA methylation (DNAm).We have followed the PRISMA protocol to select studies that analyzed DNAm at baseline and end point of a weight loss intervention using either candidate-locus or genome-wide approaches.Six genes displayed weight loss associated DNAm across four out of nine genome-wide studies. Weight loss is associated with significant but small changes in DNAm across the genome, and weight loss outcome is associated with individual differences in baseline DNAm at several genomic locations.The identified weight loss associated DNAm markers, especially those showing reproducibility across different studies, warrant validation by further studies with robust design and adequate power.

    View details for DOI 10.2217/epi-2016-0182

    View details for Web of Science ID 000401642200014

    View details for PubMedID 28517981

  • DIETFITS study (diet intervention examining the factors interacting with treatment success) - Study design and methods. Contemporary clinical trials Stanton, M. V., Robinson, J. L., Kirkpatrick, S. M., Farzinkhou, S., Avery, E. C., Rigdon, J., Offringa, L. C., Trepanowski, J. F., Hauser, M. E., Hartle, J. C., Cherin, R. J., King, A. C., Ioannidis, J. P., Desai, M., Gardner, C. D. 2017; 53: 151-161


    Numerous studies have attempted to identify successful dietary strategies for weight loss, and many have focused on Low-Fat vs. Low-Carbohydrate comparisons. Despite relatively small between-group differences in weight loss found in most previous studies, researchers have consistently observed relatively large between-subject differences in weight loss within any given diet group (e.g., ~25kg weight loss to ~5kg weight gain). The primary objective of this study was to identify predisposing individual factors at baseline that help explain differential weight loss achieved by individuals assigned to the same diet, particularly a pre-determined multi-locus genotype pattern and insulin resistance status. Secondary objectives included discovery strategies for further identifying potential genetic risk scores. Exploratory objectives included investigation of an extensive set of physiological, psychosocial, dietary, and behavioral variables as moderating and/or mediating variables and/or secondary outcomes. The target population was generally healthy, free-living adults with BMI 28-40kg/m(2) (n=600). The intervention consisted of a 12-month protocol of 22 one-hour evening instructional sessions led by registered dietitians, with ~15-20 participants/class. Key objectives of dietary instruction included focusing on maximizing the dietary quality of both Low-Fat and Low-Carbohydrate diets (i.e., Healthy Low-Fat vs. Healthy Low-Carbohydrate), and maximally differentiating the two diets from one another. Rather than seeking to determine if one dietary approach was better than the other for the general population, this study sought to examine whether greater overall weight loss success could be achieved by matching different people to different diets. Here we present the design and methods of the study.

    View details for DOI 10.1016/j.cct.2016.12.021

    View details for PubMedID 28027950

  • Is a diet low in greenhouse gas emissions a nutritious diet? - Analyses of self-selected diets in the LifeGene study. Archives of public health = Archives belges de sante publique Bälter, K., Sjörs, C., Sjölander, A., Gardner, C., Hedenus, F., Tillander, A. 2017; 75: 17-?


    Climate change is an urgent global issue and the food sector is a major contributor to greenhouse gas emissions (GHGE). Here we study if a diet low in GHGE could be a nutritious diet compared to the Nordic Nutrition Recommendations (NNR).The environmental impact of foods from Life Cycle Assessment (LCA) data was linked to a food frequency questionnaire (FFQ) filled out by 5,364 participants in the Swedish LifeGene study. Thereafter, we calculated the daily emission of CO2 equivalents (CO2e) as well as the intake of selected nutrients associated with vegetables, fruits, meat and dairy products. The CO2e was divided into quartiles were quartile 1 corresponds to a diet generating the lowest CO2e, and quartile 4 corresponds to a diet with the highest CO2e.The overall diet-related emission was 4.7 kg CO2e/day and person, corresponding to 1.7 ton CO2e/year. In general, there were only small differences in nutrient intake between groups of varying levels of CO2e, regardless if the intake was analyzed as absolute intake, energy percent or as nutrient density. Moreover, adherence to NNR was high for the group with the lowest CO2e, except for saturated fat where the intake was higher than recommended for all CO2e groups. On the other hand, only the group with the lowest CO2e fulfilled recommended intake of fiber. However, none of the CO2e groups reached the recommended intake of folate and vitamin D.Here we show that a self-selected diet low in CO2e provides comparable intake of nutrients as a diet high in in CO2e.

    View details for DOI 10.1186/s13690-017-0185-9

    View details for PubMedID 28400959

  • Food Revolution. American journal of lifestyle medicine Gardner, C. D., Hauser, M. E. 2017; 11 (5): 387–96


    Recent research has found important links between poor dietary choices, a toxic food environment, and high national and global burdens of chronic diseases. These findings serve as an impetus for a Food Revolution. The Gardner Nutrition Studies Research Group, along with a diverse range of collaborators, has been focusing on solution-oriented research to help find answers to the problems that plague the current food system. Research topics include (1) a recently completed weight loss diet study contrasting Healthy Low-Fat to Healthy Low-Carbohydrate diets among 609 overweight and obese adults; (2) a quasi-experimental study conducted among Stanford undergraduates that examined social and environmental, rather than health-focused, motivations for dietary change; (3) links between dietary fiber, the human microbiome, and immune function; and (4) ongoing collaborations with university chefs to create unapologetically delicious food for campus dining halls that is also healthy and environmentally sustainable. Most of these approaches emphasize plant-based diets. The decreased consumption of animal products has created some concern over the ability of one to obtain adequate protein intake. Evidence is presented that adequate protein is easily obtainable from vegetarian, vegan, and other diets that contain significantly less meat and fewer animal foods than the standard American diet.

    View details for PubMedID 30202360

  • Effect of a mobile app intervention on vegetable consumption in overweight adults: a randomized controlled trial. The international journal of behavioral nutrition and physical activity Mummah, S. n., Robinson, T. N., Mathur, M. n., Farzinkhou, S. n., Sutton, S. n., Gardner, C. D. 2017; 14 (1): 125


    Mobile applications (apps) have been heralded as transformative tools to deliver behavioral health interventions at scale, but few have been tested in rigorous randomized controlled trials. We tested the effect of a mobile app to increase vegetable consumption among overweight adults attempting weight loss maintenance.Overweight adults (n=135) aged 18-50 years with BMI=28-40 kg/m(2) near Stanford, CA were recruited from an ongoing 12-month weight loss trial (parent trial) and randomly assigned to either the stand-alone, theory-based Vegethon mobile app (enabling goal setting, self-monitoring, and feedback and using "process motivators" including fun, surprise, choice, control, social comparison, and competition) or a wait-listed control condition. The primary outcome was daily vegetables servings, measured by an adapted Harvard food frequency questionnaire (FFQ) 8 weeks post-randomization. Daily vegetable servings from 24-hour dietary recalls, administered by trained, certified, and blinded interviewers 5 weeks post-randomization, was included as a secondary outcome. All analyses were conducted according to principles of intention-to-treat.Daily vegetable consumption was significantly greater in the intervention versus control condition for both measures (adjusted mean difference: 2.0 servings; 95% CI: 0.1, 3.8, p=0.04 for FFQ; and 1.0 servings; 95% CI: 0.2, 1.9; p=0.02 for 24-hour recalls). Baseline vegetable consumption was a significant moderator of intervention effects (p=0.002) in which effects increased as baseline consumption increased.These results demonstrate the efficacy of a mobile app to increase vegetable consumption among overweight adults. Theory-based mobile interventions may present a low-cost, scalable, and effective approach to improving dietary behaviors and preventing associated chronic NCT01826591. Registered 27 March 2013.

    View details for PubMedID 28915825

    View details for PubMedCentralID PMC5603006

  • IDEAS (Integrate, Design, Assess, and Share): A Framework and Toolkit of Strategies for the Development of More Effective Digital Interventions to Change Health Behavior JOURNAL OF MEDICAL INTERNET RESEARCH Mummah, S. A., Robinson, T. N., King, A. C., Gardner, C. D., Sutton, S. 2016; 18 (12): 205-218


    Developing effective digital interventions to change health behavior has been a challenging goal for academics and industry players alike. Guiding intervention design using the best combination of approaches available is necessary if effective technologies are to be developed. Behavioral theory, design thinking, user-centered design, rigorous evaluation, and dissemination each have widely acknowledged merits in their application to digital health interventions. This paper introduces IDEAS, a step-by-step process for integrating these approaches to guide the development and evaluation of more effective digital interventions. IDEAS is comprised of 10 phases (empathize, specify, ground, ideate, prototype, gather, build, pilot, evaluate, and share), grouped into 4 overarching stages: Integrate, Design, Assess, and Share (IDEAS). Each of these phases is described and a summary of theory-based behavioral strategies that may inform intervention design is provided. The IDEAS framework strives to provide sufficient detail without being overly prescriptive so that it may be useful and readily applied by both investigators and industry partners in the development of their own mHealth, eHealth, and other digital health behavior change interventions.

    View details for DOI 10.2196/jmir.5927

    View details for Web of Science ID 000391065600019

    View details for PubMedID 27986647

  • Iterative development of Vegethon: a theory-based mobile app intervention to increase vegetable consumption INTERNATIONAL JOURNAL OF BEHAVIORAL NUTRITION AND PHYSICAL ACTIVITY Mummah, S. A., King, A. C., Gardner, C. D., Sutton, S. 2016; 13


    Mobile technology may serve as a cost-effective and scalable tool for delivering behavioral nutrition interventions. This research sought to iteratively develop a theory-driven mobile app, Vegethon, to increase vegetable consumption.Development of Vegethon followed phases outlined by the IDEAS framework: 1) empathize with users (qualitative interviews, n = 18); 2) specify target behavior; 3) ground in behavioral theory; 4) ideate implementation strategies; 5) prototype potential products; 6) gather user feedback (qualitative interviews, n = 14; questionnaire, n = 41); 7) build minimum viable product; and 8) pilot potential efficacy and usability (pilot RCT, n = 17). Findings from each phase informed subsequent phases. The target population that informed intervention development was 18-50 years of age, had BMIs of 28-40 kg/m(2), and lived in the geographical area surrounding Stanford University. A full description of the final version of Vegethon is included in the paper.Qualitative findings that shaped initial intervention conception were: participants' interests in accountability without judgment; their desire for simple and efficient dietary self-monitoring; and the importance of planning meals in advance. Qualitative findings identified during intervention refinement were the need for a focus on vegetable self-monitoring; inclusion of vegetable challenges; simplification of features; advice and inspiration for eating vegetables; reminder notifications; and peer comparison. Pilot RCT findings suggested the initial efficacy, acceptance, and feasibility of the intervention. The final version of Vegethon enabled easy self-monitoring of vegetable consumption and included a range of features designed to engage the user (e.g., surprise challenges; leaderboard; weekly reports). Vegethon was coded for its inclusion of 18 behavior change techniques (BCTs) (e.g., goal setting; feedback; social comparison; prompts/cues; framing/reframing; identity).Vegethon is a theory-based, user-informed mobile intervention that was systematically developed using the IDEAS framework. Vegethon targets increased vegetable consumption among overweight adults and is currently being evaluated in a randomized controlled efficacy trial.Clinical NCT01826591.

    View details for DOI 10.1186/s12966-016-0400-z

    View details for Web of Science ID 000381567700001

    View details for PubMedID 27501724

    View details for PubMedCentralID PMC4977881

  • Mobile Technology for Vegetable Consumption: A Randomized Controlled Pilot Study in Overweight Adults. JMIR mHealth and uHealth Mummah, S. A., Mathur, M., King, A. C., Gardner, C. D., Sutton, S. 2016; 4 (2)


    Mobile apps present a potentially cost-effective tool for delivering behavior change interventions at scale, but no known studies have tested the efficacy of apps as a tool to specifically increase vegetable consumption among overweight adults.The purpose of this pilot study was to assess the initial efficacy and user acceptability of a theory-driven mobile app to increase vegetable consumption.A total of 17 overweight adults aged 42.0 (SD 7.3) years with a body mass index (BMI) of 32.0 (SD 3.5) kg/m(2) were randomized to the use of Vegethon (a fully automated theory-driven mobile app enabling self-monitoring of vegetable consumption, goal setting, feedback, and social comparison) or a wait-listed control condition. All participants were recruited from an ongoing 12-month weight loss trial (parent trial). Researchers who performed data analysis were blinded to condition assignment. The primary outcome measure was daily vegetable consumption, assessed using an adapted version of the validated Harvard Food Frequency Questionnaire administered at baseline and 12 weeks after randomization. An analysis of covariance was used to assess differences in 12-week vegetable consumption between intervention and control conditions, controlling for baseline. App usability and satisfaction were measured via a 21-item post-intervention questionnaire.Using intention-to-treat analyses, all enrolled participants (intervention: 8; control: 9) were analyzed. Of the 8 participants randomized to the intervention, 5 downloaded the app and logged their vegetable consumption a mean of 0.7 (SD 0.9) times per day, 2 downloaded the app but did not use it, and 1 never downloaded it. Consumption of vegetables was significantly greater among the intervention versus control condition at the end of the 12-week pilot study (adjusted mean difference: 7.4 servings; 95% CI 1.4-13.5; P=.02). Among secondary outcomes defined a priori, there was significantly greater consumption of green leafy vegetables, cruciferous vegetables, and dark yellow vegetables (adjusted mean difference: 2.6, 1.6, and 0.8 servings; 95% CI 0.1-5.0, 0.1-3.2, and 0.3-1.4; P=.04, P=.04, and P=.004, respectively). Participants reported positive experiences with the app, including strong agreement with the statements "I have found Vegethon easy to use" and "I would recommend Vegethon to a friend" (mean 4.6 (SD 0.6) and 4.2 (SD 0.8), respectively, (on a 5-point scale).Vegethon demonstrated initial efficacy and user acceptability. A mobile app intervention may be useful for increasing vegetable consumption among overweight adults. The small sample size prevented precise estimates of effect sizes. Given the improved health outcomes associated with increases in vegetable consumption, these findings indicate the need for larger, longer-term evaluations of Vegethon and similar technologies among overweight adults and other suitable target NCT01826591; (Archived by WebCite at

    View details for DOI 10.2196/mhealth.5146

    View details for PubMedID 27193036

    View details for PubMedCentralID PMC4889871

  • Behavioral weight loss and physical activity intervention in obese adults with asthma. A randomized trial. Annals of the American Thoracic Society Ma, J., Strub, P., Xiao, L., Lavori, P. W., Camargo, C. A., Wilson, S. R., Gardner, C. D., Buist, A. S., Haskell, W. L., Lv, N. 2015; 12 (1): 1-11


    The effect of weight loss on asthma in obese adults warrants rigorous investigation.To examine an evidence-based, practical, and comprehensive lifestyle intervention targeting modest weight loss and increased physical activity for asthma control.The trial randomized 330 obese adults with uncontrolled asthma to receive usual care enhanced with a pedometer, a weight scale, information about existing weight management services at the participating clinics, and an asthma education DVD, or with these tools plus the 12-month intervention.The primary outcome was change in Asthma Control Questionnaire (ACQ) scores from baseline to 12 months. Participants (mean [SD] age, 47.6 [12.4] yr) were 70.6% women, 20.0% non-Hispanic black, 20.3% Hispanic/Latino, and 8.2% Asian/Pacific Islander. At baseline, they were obese (mean [SD] body mass index, 37.5 [5.9] kg/m(2)) and had uncontrolled asthma (Asthma Control Test score, 15.1 [3.8]). Compared with control subjects, intervention participants achieved significantly greater mean weight loss (±SE) (intervention, -4.0 ± 0.8 kg vs. control, -2.1 ± 0.8 kg; P = 0.01) and increased leisure-time activity (intervention, 418.2 ± 110.6 metabolic equivalent task-min/wk vs. control, 178.8 ± 109.1 metabolic equivalent task-min/wk; P = 0.05) at 12 months. But between-treatment mean (±SE) differences were not significant for ACQ changes (intervention, -0.3 ± 0.1 vs. control, -0.2 ± 0.1; P = 0.92) from baseline (mean [SD], 1.4 [0.8]), nor for any other clinical asthma outcomes (e.g., spirometric results and asthma exacerbations). Among all participants regardless of treatment assignment, weight loss of 10% or greater was associated with a Cohen d effect of 0.76 and with 3.78 (95% confidence interval, 1.72-8.31) times the odds of achieving clinically significant reductions (i.e., ≥0.5) on ACQ as stable weight (<3% loss or gain from baseline). The effects of other weight change categories were small.Moderately and severely obese adults with uncontrolled asthma can safely participate in evidence-based lifestyle intervention for weight loss and active living. The modest average weight and activity improvements are comparable to those shown to reduce cardiometabolic risk factors in studies of similar interventions in other populations but are not associated with significant net benefits for asthma control or other clinical asthma outcomes in the current population. Instead, weight loss of 10% or greater may be required to produce clinically meaningful improvement in asthma. Clinical trial registered with (NCT00901095).

    View details for DOI 10.1513/AnnalsATS.201406-271OC

    View details for PubMedID 25496399

    View details for PubMedCentralID PMC4342805

  • Effect of Increasing Dietary Fiber on Plasma Levels of Colon-Derived Solutes in Hemodialysis Patients CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Sirich, T. L., Plummer, N. S., Gardner, C. D., Hostetter, T. H., Meyer, T. W. 2014; 9 (9): 1603-1610


    Numerous uremic solutes are derived from the action of colon microbes. Two such solutes, indoxyl sulfate and p-cresol sulfate, have been associated with adverse outcomes in renal failure. This study tested whether increasing dietary fiber in the form of resistant starch would lower the plasma levels of these solutes in patients on hemodialysis.Fifty-six patients on maintenance hemodialysis were randomly assigned to receive supplements containing resistant starch (n=28) or control starch (n=28) daily for 6 weeks in a study conducted between October 2010 and May 2013. Of these, 40 patients (20 in each group) completed the study and were included in the final analysis. Plasma indoxyl sulfate and p-cresol sulfate levels were measured at baseline and week 6.Increasing dietary fiber for 6 weeks significantly reduced the unbound, free plasma level of indoxyl sulfate (median -29% [25th percentile, 75th percentile, -56, -12] for fiber versus -0.4% [-20, 34] for control, P=0.02). The reduction in free plasma levels of indoxyl sulfate was accompanied by a reduction in free plasma levels of p-cresol sulfate (r=0.81, P<0.001). However, the reduction of p-cresol sulfate levels was of lesser magnitude and did not achieve significance (median -28% [-46, 5] for fiber versus 4% [-28, 36] for control, P=0.05).Increasing dietary fiber in hemodialysis patients may reduce the plasma levels of the colon-derived solutes indoxyl sulfate and possibly p-cresol sulfate without the need to intensify dialysis treatments. Further studies are required to determine whether such reduction provides clinical benefits.

    View details for DOI 10.2215/CJN.00490114

    View details for Web of Science ID 000341275200016

    View details for PubMedID 25147155

    View details for PubMedCentralID PMC4152802

  • Food-and-beverage environment and procurement policies for healthier work environments NUTRITION REVIEWS Gardner, C. D., Whitsel, L. P., Thorndike, A. N., Marrow, M. W., Otten, J. J., Foster, G. D., Carson, J. A., Johnson, R. K. 2014; 72 (6): 390-410


    The importance of creating healthier work environments by providing healthy foods and beverages in worksite cafeterias, in on-site vending machines, and at meetings and conferences is drawing increasing attention. Large employers, federal and state governments, and hospital systems are significant purchasers and providers of food and beverages. The American Heart Association, federal government, and other organizations have created procurement standards to guide healthy purchasing by these entities. There is a need to review how procurement standards are currently implemented, to identify important minimum criteria for evaluating health and purchasing outcomes, and to recognize significant barriers and challenges to implementation, along with success stories. The purpose of this policy paper is to describe the role of food-and-beverage environment and procurement policy standards in creating healthier worksite environments; to review recently created national model standards; to identify elements across the standards that are important to consider for incorporation into policies; and to delineate issues to address as standards are implemented across the country.

    View details for DOI 10.1111/nure.12116

    View details for Web of Science ID 000337596800004

    View details for PubMedID 24801009

  • Digesting Dietary Data SCIENTIST Gardner, C., Stanton, M. 2014; 28 (6): 30-31
  • Ending SNAP Subsidies For Sugar-Sweetened Beverages Could Reduce Obesity And Type 2 Diabetes HEALTH AFFAIRS Basu, S., Seligman, H. K., Gardner, C., Bhattacharya, J. 2014; 33 (6): 1032-1039


    To reduce obesity and type 2 diabetes rates, lawmakers have proposed modifying Supplemental Nutrition Assistance Program (SNAP) benefits to encourage healthier food choices. We examined the impact of two proposed policies: a ban on using SNAP dollars to buy sugar-sweetened beverages; and a subsidy in which for every SNAP dollar spent on fruit and vegetables, thirty cents is credited back to participants' SNAP benefit cards. We used nationally representative data and models describing obesity, type 2 diabetes, and determinants of food consumption among a sample of over 19,000 SNAP participants. We found that a ban on SNAP purchases of sugar-sweetened beverages would be expected to significantly reduce obesity prevalence and type 2 diabetes incidence, particularly among adults ages 18-65 and some racial and ethnic minorities. The subsidy policy would not be expected to have a significant effect on obesity and type 2 diabetes, given available data. Such a subsidy could, however, more than double the proportion of SNAP participants who meet federal vegetable and fruit consumption guidelines.

    View details for DOI 10.1377/hlthaff.2013.1246

    View details for Web of Science ID 000338187200015

  • Effect of raw milk on lactose intolerance: a randomized controlled pilot study. Annals of family medicine Mummah, S., Oelrich, B., Hope, J., Vu, Q., Gardner, C. D. 2014; 12 (2): 134-141


    PURPOSE This pilot study aimed to determine whether raw milk reduces lactose malabsorption and/or lactose intolerance symptoms relative to pasteurized milk. METHODS We performed a crossover trial involving 16 adults with self-reported lactose intolerance and lactose malabsorption confirmed by hydrogen (H2) breath testing. Participants underwent 3, 8-day milk phases (raw vs 2 controls: pasteurized, soy) in randomized order separated by 1-week washout periods. On days 1 and 8 of each phase, milk consumption was 473 mL (16 oz); on days 2 to 7, milk dosage increased daily by 118 mL (4 oz), beginning with 118 mL (4 oz) on day 2 and reaching 710 mL (24 oz) on day 7. Outcomes were area under the breath H2 curve (AUC H2) and self-reported symptom severity (visual analog scales: flatulence/gas, audible bowel sounds, abdominal cramping, diarrhea). RESULTS AUC H2 (mean ± standard error of the mean) was higher for raw vs pasteurized on day 1 (113 ± 21 vs 71 ± 12 ppm·min·10(-2), respectively, P = .01) but not day 8 (72 ± 14 vs 74 ± 15 ppm·min·10(-2), respectively, P = .9). Symptom severities were not different for raw vs pasteurized on day 7 with the highest dosage (P >.7). AUC H2 and symptom severities were higher for both dairy milks compared with soy milk. CONCLUSIONS Raw milk failed to reduce lactose malabsorption or lactose intolerance symptoms compared with pasteurized milk among adults positive for lactose malabsorption. These results do not support widespread anecdotal claims that raw milk reduces the symptoms of lactose intolerance.

    View details for DOI 10.1370/afm.1618

    View details for PubMedID 24615309

    View details for PubMedCentralID PMC3948760

  • Non-nutritive sweeteners: evidence for benefit vs. risk CURRENT OPINION IN LIPIDOLOGY Gardner, C. 2014; 25 (1): 80-84


    Intake of added sugars in the American diet is high and has been linked to weight gain and adverse effects on glycemic control and diabetes. Several national health organizations recommend decreasing added sugars intake. Among the many strategies to consider to achieve this reduction is substitution with non-nutritive sweeteners (NNS - artificial sweeteners and stevia). The purpose of this review is to critically examine existing evidence for this strategy.Short-term intervention studies suggest that NNS, when substituted for added sugars, may be useful in supporting energy intake reduction, and promoting glycemic control and weight management. However, the magnitude of effect in these studies has ranged from modest to null. Compensatory eating behaviors likely diminish, and in some cases negate, potential effects. Findings from longer-term observational studies that examine associations between NNS use and obesity or type 2 diabetes are potentially confounded by reverse causality.Existing data are insufficient to clearly support or refute the effectiveness of substitution with NNS as a means of reducing added sugar intake. It is important to not lose sight of the impact of incorporating NNS-containing beverages and foods on overall diet quality when assessing potential health benefits vs. risks.

    View details for DOI 10.1097/MOL.0000000000000034

    View details for Web of Science ID 000329437800012

    View details for PubMedID 24345988

  • Impact of San Francisco's toy ordinance on restaurants and children's food purchases, 2011-2012. Preventing chronic disease Otten, J. J., Saelens, B. E., Kapphahn, K. I., Hekler, E. B., Buman, M. P., Goldstein, B. A., Krukowski, R. A., O'Donohue, L. S., Gardner, C. D., King, A. C. 2014; 11: E122-?


    In 2011, San Francisco passed the first citywide ordinance to improve the nutritional standards of children's meals sold at restaurants by preventing the giving away of free toys or other incentives with meals unless nutritional criteria were met. This study examined the impact of the Healthy Food Incentives Ordinance at ordinance-affected restaurants on restaurant response (eg, toy-distribution practices, change in children's menus), and the energy and nutrient content of all orders and children's-meal-only orders purchased for children aged 0 through 12 years.Restaurant responses were examined from January 2010 through March 2012. Parent-caregiver/child dyads (n = 762) who were restaurant customers were surveyed at 2 points before and 1 seasonally matched point after ordinance enactment at Chain A and B restaurants (n = 30) in 2011 and 2012.Both restaurant chains responded to the ordinance by selling toys separately from children's meals, but neither changed their menus to meet ordinance-specified nutrition criteria. Among children for whom children's meals were purchased, significant decreases in kilocalories, sodium, and fat per order were likely due to changes in children's side dishes and beverages at Chain A.Although the changes at Chain A did not appear to be directly in response to the ordinance, the transition to a more healthful beverage and default side dish was consistent with the intent of the ordinance. Study results underscore the importance of policy wording, support the concept that more healthful defaults may be a powerful approach for improving dietary intake, and suggest that public policies may contribute to positive restaurant changes.

    View details for DOI 10.5888/pcd11.140026

    View details for PubMedID 25032837

    View details for PubMedCentralID PMC4110247

  • Effect of fish oil supplementation on serum triglycerides, LDL cholesterol and LDL subfractions in hypertriglyceridemic adults NUTRITION METABOLISM AND CARDIOVASCULAR DISEASES Oelrich, B., Dewell, A., Gardner, C. D. 2013; 23 (4): 350-357


    The well-established triglyceride (TG) lowering effect of fish oil is accompanied by an increase in LDL-cholesterol (LDL-C) concentration. Less is known about the differential impact on LDL particle distribution - the smaller particles being associated with a greater risk for atherosclerosis. We aimed to examine the changes in serum concentrations of four subclasses of LDL particles as well as shifts in LDL phenotype patterns (A, B, AB) among hypertriglyceridemic adults.This was a secondary analysis from a double-blind, parallel design, placebo controlled trial with 42 adults that experienced significant TG lowering and modest increases in total LDL-C concentrations after 12 weeks of 4 g/d EPA + DHA. Reduction in serum TG concentrations (mean ± SEM) was -26 ± 4% (-0.81 ± 10.12 mmol/L), p < 0.0001. Total LDL-C concentration increased by 13 ± 3% (+0.31 ± 0.08 mmol/L), p < 0.0001. The 12-week changes in concentrations of LDL1, LDL2, LDL3 and LDL4 were +0.06 ± 0.02 mmol/L [+2.2 ± 0.7 mg/dL], +0.07 ± 0.03 mmol/L [+2.6 ± 1.0 mg/dL], +0.16 ± 0.05 mmol/L [+6.3 ± 1.8 mg/dL], and +0.04 ± 0.04 mmol/L [+1.4 ± 1.7 mg/dL], respectively (+20 ± 5%, +64 ± 13%, +26 ± 6%, and +17 ± 9%), p < 0.05 for all but LDL4. Changes in LDL phenotype patterns A, B and A/B were negligible and not statistically significant.In this population of hypertriglyceridemic adults, dietary supplementation with fish oil resulted in an increase in total LDL-C concentration which was distributed relatively evenly across the range of smaller and more atherogenic as well as larger and less atherogenic LDL particles.

    View details for DOI 10.1016/j.numecd.2011.06.003

    View details for Web of Science ID 000316763400011

    View details for PubMedID 21924882

  • Incorporating Prototyping and Iteration Into Intervention Development: A Case Study of a Dining Hall-Based Intervention JOURNAL OF AMERICAN COLLEGE HEALTH McClain, A. D., Hekler, E. B., Gardner, C. D. 2013; 61 (2): 122-131


    Previous research from the fields of computer science and engineering highlight the importance of an iterative design process (IDP) to create more creative and effective solutions.This study describes IDP as a new method for developing health behavior interventions and evaluates the effectiveness of a dining hall-based intervention developed using IDP on college students' eating behavior and values. Participants: participants were 458 students (52.6% female, age = 19.6 ± 1.5 years [M ± SD]).The intervention was developed via an IDP parallel process. A cluster-randomized controlled study compared differences in eating behavior among students in 4 university dining halls (2 intervention, 2 control).The final intervention was a multicomponent, point-of-selection marketing campaign. Students in the intervention dining halls consumed significantly less junk food and high-fat meat and increased their perceived importance of eating a healthful diet relative to the control group.IDP may be valuable for the development of behavior change interventions.

    View details for DOI 10.1080/07448481.2012.755189

    View details for Web of Science ID 000315773900009

    View details for PubMedID 23409862

    View details for PubMedCentralID PMC3578232

  • Adherence to a low-fat vs. low-carbohydrate diet differs by insulin resistance status DIABETES OBESITY & METABOLISM McClain, A. D., Otten, J. J., Hekler, E. B., Gardner, C. D. 2013; 15 (1): 87-90


    Previous research shows diminished weight loss success in insulin-resistant (IR) women assigned to a low-fat (LF) diet compared to those assigned to a low-carbohydrate (LC) diet. These secondary analyses examined the relationship between insulin-resistance status and dietary adherence to either a LF-diet or LC-diet among 81 free-living, overweight/obese women [age = 41.9 ± 5.7 years; body mass index (BMI) = 32.6 ± 3.6 kg/m(2)]. This study found differential adherence by insulin-resistance status only to a LF-diet, not a LC-diet. IR participants were less likely to adhere and lose weight on a LF-diet compared to insulin-sensitive (IS) participants assigned to the same diet. There were no significant differences between IR and IS participants assigned to LC-diet in relative adherence or weight loss. These results suggest that insulin resistance status may affect dietary adherence to weight loss diets, resulting in higher recidivism and diminished weight loss success of IR participants advised to follow LF-diets for weight loss.

    View details for DOI 10.1111/j.1463-1326.2012.01668.x

    View details for Web of Science ID 000312303500013

    View details for PubMedID 22831182

    View details for PubMedCentralID PMC3504183

  • Nonnutritive Sweeteners: Current Use and Health Perspectives. A Scientific Statement from the American Heart Association and the American Diabetes Association DIABETES CARE Gardner, C., Wylie-Rosett, J., Gidding, S. S., Steffen, L. M., Johnson, R. K., Reader, D., Lichtenstein, A. H. 2012; 35 (8): 1798-1808

    View details for DOI 10.2337/dc12-9002

    View details for Web of Science ID 000306891200030

    View details for PubMedID 22778165

    View details for PubMedCentralID PMC3402256

  • Nonnutritive Sweeteners: Current Use and Health Perspectives A Scientific Statement From the American Heart Association and the American Diabetes Association CIRCULATION Gardner, C., Wylie-Rosett, J., Gidding, S. S., Johnson, R. K., Reader, D., Lichtenstein, A. H. 2012; 126 (4): 509-519
  • What We Don't Know: Unanswered Questions about Childhood Obesity CHILDHOOD OBESITY Katz, D. L., Daniels, S., Gardner, C. D., Goodman, E., Hassink, S., Sothern, M. 2012; 8 (1): 7-12

    View details for DOI 10.1089/chi.2011.0800.roun

    View details for Web of Science ID 000208946900005

    View details for PubMedID 22799470

  • Food Marketing to Children Through Toys Response of Restaurants to the First U.S. Toy Ordinance AMERICAN JOURNAL OF PREVENTIVE MEDICINE Otten, J. J., Hekler, E. B., Krukowski, R. A., Buman, M. P., Saelens, B. E., Gardner, C. D., King, A. C. 2012; 42 (1): 56-60


    On August 9, 2010, Santa Clara County CA became the first U.S. jurisdiction to implement an ordinance that prohibits the distribution of toys and other incentives to children in conjunction with meals, foods, or beverages that do not meet minimal nutritional criteria. Restaurants had many different options for complying with this ordinance, such as introducing more healthful menu options, reformulating current menu items, or changing marketing or toy distribution practices.To assess how ordinance-affected restaurants changed their child menus, marketing, and toy distribution practices relative to non-affected restaurants.Children's menu items and child-directed marketing and toy distribution practices were examined before and at two time points after ordinance implementation (from July through November 2010) at ordinance-affected fast-food restaurants compared with demographically matched unaffected same-chain restaurants using the Children's Menu Assessment tool.Affected restaurants showed a 2.8- to 3.4-fold improvement in Children's Menu Assessment scores from pre- to post-ordinance with minimal changes at unaffected restaurants. Response to the ordinance varied by restaurant. Improvements were seen in on-site nutritional guidance; promotion of healthy meals, beverages, and side items; and toy marketing and distribution activities.The ordinance appears to have positively influenced marketing of healthful menu items and toys as well as toy distribution practices at ordinance-affected restaurants, but did not affect the number of healthful food items offered.

    View details for DOI 10.1016/j.amepre.2011.08.020

    View details for Web of Science ID 000298294000011

    View details for PubMedID 22176847

  • What we don't know: unanswered questions about childhood obesity Childhood Obesity Katz, D. L., Daniels, S., Gardner, C. D., Goodman, E., Hassink, S., Sothern, M. 2012; 8 (1): 7-12
  • Low- and High-Dose Plant and Marine (n-3) Fatty Acids Do Not Affect Plasma Inflammatory Markers in Adults with Metabolic Syndrome JOURNAL OF NUTRITION Dewell, A., Marvasti, F. F., Harris, W. S., Tsao, P., Gardner, C. D. 2011; 141 (12): 2166-2171


    Chronic inflammation is considered to play a role in the development of cardiovascular disease. Various (n-3) fatty acids (FA) have been reported to have antiinflammatory effects, but there is a lack of consensus in this area, particularly in regard to optimal source(s) and dose(s). This study aimed to determine the effects of high and low doses of (n-3) FA from plant and marine sources on plasma inflammatory marker concentrations. One-hundred adults with metabolic syndrome were randomly assigned to a low or high dose of plant- (2.2 or 6.6 g/d α-linolenic acid) or marine- (1.2 or 3.6 g/d EPA and DHA) derived (n-3) FA or placebo for 8 wk, using a parallel arm design (n = 20/arm). Fasting blood samples collected at 0, 4, and 8 wk were analyzed for concentrations of monocyte chemotactic protein-1 (MCP-1), IL-6, and soluble intercellular adhesion molecule-1 (sICAM-1) and for cardiovascular risk factors. Baseline concentrations across all 5 groups combined were (mean ± SD) 103 ± 32 ng/L for MCP-1, 1.06 ± 0.56 ng/L for IL-6, and 0.197 ± 0.041 ng/L for sICAM-1. There were no significant differences in 8-wk changes in plasma inflammatory marker concentrations among the 5 groups. Plasma TG and blood pressure decreased significantly more and the LDL cholesterol concentration increased more in the high-dose fish oil group compared to the 8-wk changes in some of the other 4 groups (P ≤ 0.04). In conclusion, no beneficial effects were detected for any of the 3 inflammatory markers investigated in response to (n-3) FA in adults with metabolic syndrome regardless of dose or source.

    View details for DOI 10.3945/jn.111.142240

    View details for Web of Science ID 000297387200011

    View details for PubMedID 22031659

    View details for PubMedCentralID PMC3223874

  • Incorporation of whole, ancient grains into a modern Asian Indian diet to reduce the burden of chronic disease NUTRITION REVIEWS Dixit, A. A., Azar, K. M., Gardner, C. D., Palaniappan, L. P. 2011; 69 (8): 479-488


    Refined carbohydrates, such as white rice and white flour, are the mainstay of the modern Asian Indian diet, and may contribute to the rising incidence of type 2 diabetes and cardiovascular disease in this population. Prior to the 1950s, whole grains such as amaranth, barley, brown rice, millet, and sorghum were more commonly used in Asian Indian cooking. These grains and other non-Indian grains such as couscous, quinoa, and spelt are nutritionally advantageous and may be culturally acceptable carbohydrate substitutes for Asian Indians. This review focuses on practical recommendations for culturally sensitive carbohydrate modification in a modern Asian Indian diet to reduce type 2 diabetes and cardiovascular disease in this population.

    View details for DOI 10.1111/j.1753-4887.2011.00411.x

    View details for Web of Science ID 000293176900005

    View details for PubMedID 21790614

    View details for PubMedCentralID PMC3146027

  • CHANGES AT FAST-FOOD RESTAURANTS IN RESPONSE TO THE 2010 SANTA CLARA COUNTY, CA TOY ORDINANCE Otten, J., Buman, M., Krukowski, R. A., Hekler, E., Saelens, B. E., Gardner, C., King, A. SPRINGER. 2011: S25
  • Outcome expectations and realizations as predictors of weight regain among dieters EATING BEHAVIORS Moore, S. D., King, A. C., Kiernan, M., Gardner, C. D. 2011; 12 (1): 60-63


    This prospective study tested whether (a) baseline outcome expectations regarding the benefits of a weight-loss diet, (b) 6-month outcome realizations regarding perceived benefits actually experienced, and/or (c) the interaction between them predicted 6-12-month weight regain among overweight/obese women randomized to one of four popular weight-loss diets (N=311). Positive 6-month realizations regarding improvements in physical shape and appearance predicted less 6-12-month weight regain among Atkins diet participants only (n=70), controlling for baseline expectations, the expectations-realization interaction, and initial weight loss. Atkins participants displayed three distinct patterns of regain based on levels of 6-month realizations and initial weight loss. Experimental research should investigate whether improving realizations leads to reduced weight regain in response to this popular diet.

    View details for DOI 10.1016/j.eatbeh.2010.08.007

    View details for Web of Science ID 000286845700010

    View details for PubMedID 21184975

    View details for PubMedCentralID PMC3053006

  • No Beneficial Effects of Pine Bark Extract on Cardiovascular Disease Risk Factors ARCHIVES OF INTERNAL MEDICINE Drieling, R. L., Gardner, C. D., Ma, J., Ahn, D. K., Stafford, R. S. 2010; 170 (17): 1541-1547


    Although modifiable cardiovascular disease risk factors are common, some patients eschew conventional drug treatments in favor of natural alternatives. Pine bark extract, a dietary supplement source of antioxidant oligomeric proanthocyanidin complexes, has multiple putative cardiovascular benefits. Studies published to date about the supplement have notable methodological limitations.We randomized 130 individuals with increased cardiovascular disease risk to take 200 mg of a water-based extract of pine bark (n = 64; Toyo-FVG, Toyo Bio-Pharma, Torrance, California; Shinyaku Co, Ltd, Saga, Japan; also marketed as Flavagenol in Japan) or placebo (n = 66) once per day. Blood pressure, our primary outcome, and other cardiovascular disease risk factors were measured at baseline and at 6 and 12 weeks. Statistical analyses were conducted using regression models.Baseline characteristics did not differ between the study groups. Over the 12-week intervention, the sum of systolic and diastolic blood pressures decreased by 1.0 mm Hg (95% confidence interval, -4.2 to 2.1 mm Hg) in the pine bark extract-treated group and by 1.9 mm Hg (-5.5 to 1.7 mm Hg) in the placebo group (P = .87). Other outcomes were likewise not significantly different, including body mass index, lipid panel measures, liver transaminase test results, lipoprotein cholesterol particle size, and levels of insulin, lipoprotein(a), fasting glucose, and high-sensitivity C-reactive protein. There were no subgroups for whom intake of pine bark extract affected cardiovascular disease risk factors.This pine bark extract (at a dosage of 200 mg/d) was safe but was not associated with improvement in cardiovascular disease risk factors. Although variations among participants, dosages, and chemical preparations could contribute to different findings compared with past studies, our results are consistent with a general failure of antioxidants to demonstrate cardiovascular Identifier: NCT00425945.

    View details for Web of Science ID 000282286700004

    View details for PubMedID 20876405

  • Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study AMERICAN JOURNAL OF CLINICAL NUTRITION Gardner, C. D., Kim, S., Bersamin, A., Dopler-Nelson, M., Otten, J., Oelrich, B., Cherin, R. 2010; 92 (2): 304-312


    Information on the micronutrient quality of alternative weight-loss diets is limited, despite the significant public health relevance.Micronutrient intake was compared between overweight or obese women randomly assigned to 4 popular diets that varied primarily in macronutrient distribution.Dietary data were collected from women in the Atkins (n = 73), Zone (n = 73), LEARN (Lifestyle, Exercise, Attitudes, Relationships, Nutrition) (n = 73), and Ornish (n = 72) diet groups by using 3-d, unannounced 24-h recalls at baseline and after 8 wk of instruction. Nutrient intakes were compared between groups at 8 wk and within groups for 8-wk changes in risk of micronutrient inadequacy.At 8 wk, significant differences were observed between groups for all macronutrients and for many micronutrients (P < 0.0001). Energy intake decreased from baseline in all 4 groups but was similar between groups. At 8 wk, a significant proportion of individuals shifted to intakes associated with risk of inadequacy (P < 0.05) in the Atkins group for thiamine, folic acid, vitamin C, iron, and magnesium; in the LEARN group for vitamin E, thiamine, and magnesium; and in the Ornish group for vitamins E and B-12 and zinc. In contrast, for the Zone group, the risk of inadequacy significantly decreased for vitamins A, E, K, and C (P < 0.05), and no significant increases in risk of inadequacy were observed for other micronutrients.Weight-loss diets that focus on macronutrient composition should attend to the overall quality of the diet, including the adequacy of micronutrient intakes. Concerning calorie-restricted diets, there may be a micronutrient advantage to diets providing moderately low carbohydrate amounts and that contain nutrient-dense foods.

    View details for DOI 10.3945/ajcn.2010.29468

    View details for Web of Science ID 000280149700007

    View details for PubMedID 20573800

    View details for PubMedCentralID PMC2904033

  • Low-carbohydrate ketogenic diet and the combination of orlistat with a low-fat diet lead to comparable improvements in weight and blood lipids, but LCKD more beneficial for blood pressure. Evidence-based medicine Gardner, C. D. 2010; 15 (3): 91-92

    View details for DOI 10.1136/ebm1065

    View details for PubMedID 20522693

  • Effects of a College Course About Food and Society on Students' Eating Behaviors AMERICAN JOURNAL OF PREVENTIVE MEDICINE Hekler, E. B., Gardner, C. D., Robinson, T. N. 2010; 38 (5): 543-547


    Health education programs for promoting a healthful diet have shown limited success in clinical trials.This paper aims to examine whether an innovative educational course focused on societal-level issues related to food and food production (Food and Society) would promote healthful eating among college students.A quasi-experimental non-RCT was conducted to compare changes in eating behaviors among students taking the Food and Society course (n=28) versus students taking health-related human biology courses about obesity, health psychology, and community health assessment (n=72). All participants were undergraduates. A Food Frequency Questionnaire was administered at the beginning and end of the four courses taught from January through March 2009. Students in the Food and Society course read selected portions of popular books and essays (e.g., Michael Pollan's Omnivore's Dilemma) and watched documentaries (e.g., Aaron Woolf's King Corn) highlighting environmental, ethical, social justice, cultural, political, and agricultural issues related to food and food production, and discussed these major themes during class sessions. In addition, students were required to (1) write an Op-Ed article and (2) create a brief YouTube video focused on themes discussed in the course.The students who took the Food and Society course reported significantly improving their healthful eating (F[2, 97]=5.72, p=0.02), with greatest improvements in increased vegetable (F[2, 97]=10.96, p=0.001) and decreased high-fat dairy (F[2, 97]=5.39, p=0.02) intakes relative to the comparison group.The results suggest that it may be possible to change dietary behaviors in college students by focusing on social, ethical, cultural, and environmental issues related to food and food production.

    View details for DOI 10.1016/j.amepre.2010.01.026

    View details for Web of Science ID 000277213500011

    View details for PubMedID 20227847

  • Weight-Loss Diet Studies: Is the Most Rigorous Trial To Date Generalizable to Public Health? CURRENT CARDIOVASCULAR RISK REPORTS Nelson, M., Otten, J., Oelrich, B., Gardner, C. 2010; 4 (2): 86-88
  • The Breathe Easier through Weight Loss Lifestyle (BE WELL) Intervention: a randomized controlled trial. BMC pulmonary medicine Ma, J., Strub, P., Camargo, C. A., Xiao, L., Ayala, E., Gardner, C. D., Buist, A. S., Haskell, W. L., Lavori, P. W., Wilson, S. R. 2010; 10: 16-?


    Obesity and asthma have reached epidemic proportions in the US. Their concurrent rise over the last 30 years suggests that they may be connected. Numerous observational studies support a temporally-correct, dose-response relationship between body mass index (BMI) and incident asthma. Weight loss, either induced by surgery or caloric restriction, has been reported to improve asthma symptoms and lung function. Due to methodological shortcomings of previous studies, however, well-controlled trials are needed to investigate the efficacy of weight loss strategies to improve asthma control in obese individuals.BE WELL is a 2-arm parallel randomized clinical trial (RCT) of the efficacy of an evidence-based, comprehensive, behavioral weight loss intervention, focusing on diet, physical activity, and behavioral therapy, as adjunct therapy to usual care in the management of asthma in obese adults. Trial participants (n = 324) are patients aged 18 to 70 years who have suboptimally controlled, persistent asthma, BMI between 30.0 and 44.9 kg/m2, and who do not have serious comorbidities (e.g., diabetes, heart disease, stroke). The 12-month weight loss intervention to be studied is based on the principles of the highly successful Diabetes Prevention Program lifestyle intervention. Intervention participants will attend 13 weekly group sessions over a four-month period, followed by two monthly individual sessions, and will then receive individualized counseling primarily by phone, at least bi-monthly, for the remainder of the intervention. Follow-up assessment will occur at six and 12 months. The primary outcome variable is the overall score on the Juniper Asthma Control Questionnaire measured at 12 months. Secondary outcomes include lung function, asthma-specific and general quality of life, asthma medication use, asthma-related and total health care utilization. Potential mediators (e.g., weight loss and change in physical activity level and nutrient intake) and moderators (e.g., socio-demographic characteristics and comorbidities) of the intervention effects also will be examined.This RCT holds considerable potential for illuminating the nature of the obesity-asthma relationship and advancing current guidelines for treating obese adults with asthma, which may lead to reduced morbidity and mortality related to the comorbidity of the two disorders.NCT00901095.

    View details for DOI 10.1186/1471-2466-10-16

    View details for PubMedID 20334686

    View details for PubMedCentralID PMC2860346

  • The Breathe Easier through Weight Loss Lifestyle (BE WELL) Intervention: A randomized controlled trial BMC PULMONARY MEDICINE Ma, J., Strub, P., Camargo, C. A., Xiao, L., Ayala, E., Gardner, C. D., Buist, A. S., Haskell, W. L., Lavori, P. W., Wilson, S. R. 2010; 10


    Obesity and asthma have reached epidemic proportions in the US. Their concurrent rise over the last 30 years suggests that they may be connected. Numerous observational studies support a temporally-correct, dose-response relationship between body mass index (BMI) and incident asthma. Weight loss, either induced by surgery or caloric restriction, has been reported to improve asthma symptoms and lung function. Due to methodological shortcomings of previous studies, however, well-controlled trials are needed to investigate the efficacy of weight loss strategies to improve asthma control in obese individuals.BE WELL is a 2-arm parallel randomized clinical trial (RCT) of the efficacy of an evidence-based, comprehensive, behavioral weight loss intervention, focusing on diet, physical activity, and behavioral therapy, as adjunct therapy to usual care in the management of asthma in obese adults. Trial participants (n = 324) are patients aged 18 to 70 years who have suboptimally controlled, persistent asthma, BMI between 30.0 and 44.9 kg/m2, and who do not have serious comorbidities (e.g., diabetes, heart disease, stroke). The 12-month weight loss intervention to be studied is based on the principles of the highly successful Diabetes Prevention Program lifestyle intervention. Intervention participants will attend 13 weekly group sessions over a four-month period, followed by two monthly individual sessions, and will then receive individualized counseling primarily by phone, at least bi-monthly, for the remainder of the intervention. Follow-up assessment will occur at six and 12 months. The primary outcome variable is the overall score on the Juniper Asthma Control Questionnaire measured at 12 months. Secondary outcomes include lung function, asthma-specific and general quality of life, asthma medication use, asthma-related and total health care utilization. Potential mediators (e.g., weight loss and change in physical activity level and nutrient intake) and moderators (e.g., socio-demographic characteristics and comorbidities) of the intervention effects also will be examined.This RCT holds considerable potential for illuminating the nature of the obesity-asthma relationship and advancing current guidelines for treating obese adults with asthma, which may lead to reduced morbidity and mortality related to the comorbidity of the two disorders.NCT00901095.

    View details for DOI 10.1186/1471-2466-10-16

    View details for Web of Science ID 000208592700016

    View details for PubMedCentralID PMC2860346

  • Prostatic Soy Isoflavone Concentrations Exceed Serum Levels After Dietary Supplementation PROSTATE Gardner, C. D., Oelrich, B., Liu, J. P., Feldman, D., Franke, A. A., Brooks, J. D. 2009; 69 (7): 719-726


    The effects of soy isoflavones on prostate cancer may be concentration-dependent. The impact of soy supplementation on isoflavone concentrations in prostate tissues and serum remain unclear.To assess and compare concentrations of soy isoflavones in prostate tissue and serum among 19 men with prostate cancer who had elected to undergo radical prostatectomy.Participants were randomized to receive either daily soy supplements (82 mg/day aglycone equivalents) or placebos for 2 weeks (14 days) prior to surgery. Serum samples were obtained at the time of the surgery. Isoflavone concentrations were measured by HPLC/ESI-MS-MS.The median (25th, 75th percentile) total isoflavone concentration in the isoflavone-supplemented group was 2.3 micromol/L (1.2, 6.9) in the prostate tissue and 0.7 micromol/L (0.2, 1.2) in the serum. Total isoflavone concentrations in this group were an average of approximately 6-fold higher in prostate tissue compared to serum; the tissue versus serum ratio was significantly lower for genistein than daidzein, 4-fold versus 10-fold, P = 0.003. Tissue and serum levels of isoflavones among the placebo group were negligible with a few exceptions.The findings from the present study suggest that prostate tissue may have the ability to concentrate dietary soy isoflavones to potentially anti-carcinogenic levels.

    View details for DOI 10.1002/pros.20922

    View details for Web of Science ID 000265727700004

    View details for PubMedID 19180569

    View details for PubMedCentralID PMC2734961

  • Inhibition of prostaglandin synthesis and actions by genistein in human prostate cancer cells and by soy isoflavones in prostate cancer patients INTERNATIONAL JOURNAL OF CANCER Swami, S., Krishnan, A. V., Moreno, J., Bhattacharya, R. S., Gardner, C., Brooks, J. D., Peehl, D. M., Feldman, D. 2009; 124 (9): 2050-2059


    Soy and its constituent isoflavone genistein inhibit the development and progression of prostate cancer (PCa). Our study in both cultured cells and PCa patients reveals a novel pathway for the actions of genistein, namely the inhibition of the synthesis and biological actions of prostaglandins (PGs), known stimulators of PCa growth. In the cell culture experiments, genistein decreased cyclooxygenase-2 (COX-2) mRNA and protein expression in both human PCa cell lines (LNCaP and PC-3) and primary prostate epithelial cells and increased 15-hydroxyprostaglandin dehydrogenase (15-PGDH) mRNA levels in primary prostate cells. As a result genistein significantly reduced the secretion of PGE(2) by these cells. EP4 and FP PG receptor mRNA were also reduced by genistein, providing an additional mechanism for the suppression of PG biological effects. Further, the growth stimulatory effects of both exogenous PGs and endogenous PGs derived from precursor arachidonic acid were attenuated by genistein. We also performed a pilot randomised double blind clinical study in which placebo or soy isoflavone supplements were given to PCa patients in the neo-adjuvant setting for 2 weeks before prostatectomy. Gene expression changes were measured in the prostatectomy specimens. In PCa patients ingesting isoflavones, we observed significant decreases in prostate COX-2 mRNA and increases in p21 mRNA. There were significant correlations between COX-2 mRNA suppression, p21 mRNA stimulation and serum isoflavone levels. We propose that the inhibition of the PG pathway contributes to the beneficial effect of soy isoflavones in PCa chemoprevention and/or treatment.

    View details for DOI 10.1002/ijc.24161

    View details for Web of Science ID 000264647600007

    View details for PubMedID 19127598

  • Effects of isoflavone supplements vs. soy foods on blood concentrations of genistein and daidzein in adults JOURNAL OF NUTRITIONAL BIOCHEMISTRY Gardner, C. D., Chatterjee, L. M., Franke, A. A. 2009; 20 (3): 227-234


    The objective of this investigation was to examine the pharmacokinetics of isoflavone concentrations over a 24-h period among healthy adults consuming either soy foods or soy isoflavone tablets at different doses. This randomized, cross-over trial was conducted with 12 generally healthy adults. The three phases of the intervention included isoflavone tablets at (1) 144 mg/day or (2) 288 mg/day and (3) soy foods designed to provide a calculated 96 mg isoflavones/day (doses in aglycone equivalents). Doses were spread out over three meals per day. After 6 days on each study phase, plasma isoflavone concentrations were determined on the seventh day at 0, 4, 8, 10, 12 and 24 h. Average levels of total isoflavone concentrations at 8, 10 and 12 h were >4 micromol/L for the soy food phase and for the higher dose tablet phase. Genistein concentrations were higher overall in the soy food vs. both the lower and the higher dose supplement phases of the study (P<.05). When comparing plasma concentrations for the two doses of tablets, saturation appeared more evident for genistein than for daidzein at the higher dose level. In conclusion, we observed important differences in the pharmacokinetics of genistein and daidzein contrasting the sources and doses of isoflavones when administered three times daily, including a possible advantage for increasing serum concentrations of isoflavones from consuming soy foods relative to isoflavone supplements.

    View details for DOI 10.1016/j.jnutbio.2008.02.008

    View details for Web of Science ID 000263406400011

    View details for PubMedID 18602820

    View details for PubMedCentralID PMC3519237

  • Drinking Water Is Associated With Weight Loss in Overweight Dieting Women Independent of Diet and Activity OBESITY Stookey, J. D., Constant, F., Popkin, B. M., Gardner, C. D. 2008; 16 (11): 2481-2488


    Data from short-term experiments suggest that drinking water may promote weight loss by lowering total energy intake and/or altering metabolism. The long-term effects of drinking water on change in body weight and composition are unknown, however.This study tested for associations between absolute and relative increases in drinking water and weight loss over 12 months.Secondary analyses were conducted on data from the Stanford A TO Z weight loss intervention on 173 premenopausal overweight women (aged 25-50 years) who reported <1 l/day drinking water at baseline. Diet, physical activity, body weight, percent body fat (dual-energy X-ray absorptiometry), and waist circumference were assessed at baseline, 2, 6, and 12 months. At each time point, mean daily intakes of drinking water, noncaloric, unsweetened caloric (e.g., 100% fruit juice, milk) and sweetened caloric beverages, and food energy and nutrients were estimated using three unannounced 24-h diet recalls. Beverage intake was expressed in absolute (g) and relative terms (% of beverages). Mixed models were used to test for effects of absolute and relative increases in drinking water on changes in weight and body composition, controlling for baseline status, diet group, and changes in other beverage intake, the amount and composition of foods consumed and physical activity.Absolute and relative increases in drinking water were associated with significant loss of body weight and fat over time, independent of covariates.The results suggest that drinking water may promote weight loss in overweight dieting women.

    View details for DOI 10.1038/oby.2008.409

    View details for Web of Science ID 000260631700016

    View details for PubMedID 18787524

  • Effect of Ginkgo biloba (EGb 761) on treadmill walking time among adults with peripheral artery disease - A randomized clinical trial JOURNAL OF CARDIOPULMONARY REHABILITATION AND PREVENTION Gardner, C. D., Taylor-Piliae, R. E., Kiazand, A., Nicholus, J., Rigby, A. J., Farquhar, J. W. 2008; 28 (4): 258-265


    Medical therapies for treatment of peripheral artery disease (PAD) are limited. Ginkgo biloba has been reported to increase maximal and pain-free walking distance among patients with PAD; however, the evidence is inconsistent. The objective of this study was to compare the effects of 300 mg/d of Ginkgo biloba (EGb 761) versus placebo on treadmill walking time and related cardiovascular measures among patients with PAD.A double-blind, placebo-controlled, parallel design trial with a 4-month duration was used. Participants were 62 adults, aged 70 +/- 8 years (mean +/- SD), with claudication symptoms of PAD. The primary study outcomes were maximal and pain-free walking time on a treadmill. Secondary outcomes included flow-mediated vasodilation, a measure of antioxidant status as assessed by determining antibody levels to epitopes of oxidized low-density lipoprotein, and questionnaires addressing walking impairment and quality of life.Maximal treadmill walking time increased by 20 +/- 80 and 91 +/- 242 seconds in the placebo and the EGb 761 groups, respectively (P = .12). Pain-free walking time increased by 15 +/- 31 and 21 +/- 43 seconds, respectively (P = .28). No significant differences were detected between groups for any of the secondary outcomes.In older adults with PAD, Ginkgo biloba produced a modest but insignificant increase in maximal treadmill walking time and flow-mediated vasodilation. These data do not support the use of Ginkgo biloba as an effective therapy for PAD, although a longer duration of use should be considered in any future trials.

    View details for Web of Science ID 000258583000005

    View details for PubMedID 18628657

  • Using hand-held computer technologies to improve dietary intake AMERICAN JOURNAL OF PREVENTIVE MEDICINE Atienza, A. A., King, A. C., Oliveira, B. M., Ahn, D. K., Gardner, C. D. 2008; 34 (6): 514-518


    Portable hand-held information technology offers much promise not only in assessing dietary intake in the real world, but also in providing dietary feedback to individuals. However, stringent research designs have not been employed to examine whether it can be effective in modifying dietary behaviors. The purpose of this pilot study was to evaluate the efficacy of a hand-held computer (i.e., personal digital assistant [PDA]) for increasing vegetable and whole-grain intake over 8 weeks in mid-life and older adults, using a randomized study design.Twenty-seven healthy adults aged > or =50 were randomized and completed the 8-week study. Intervention participants received an instructional session and a PDA programmed to monitor their vegetable and whole-grain intake levels twice per day and to provide daily individualized feedback, goal-setting, and support. Controls received standard, age-appropriate, written nutritional education materials. Dietary intake was assessed via the Block Food Frequency Questionnaire at baseline and 8 weeks.Relative to controls, intervention participants reported significantly greater increases in vegetable servings (1.5-2.5 servings/day; p=0.02), as well as a trend toward greater intake of dietary fiber from grains (3.7-4.5 servings/day; p=0.10).This study's findings provide preliminary evidence that using portable hand-held technology to provide daily individualized feedback on dietary behavior in the real world can increase the dietary intake of healthy food groups.

    View details for DOI 10.1016/j.amepre.2008.01.034

    View details for Web of Science ID 000256169500009

    View details for PubMedID 18471588

  • Dietary adherence and weight loss success among overweight women: results from the A TO Z weight loss study INTERNATIONAL JOURNAL OF OBESITY Alhassan, S., Kim, S., Bersamin, A., King, A. C., Gardner, C. D. 2008; 32 (6): 985-991


    Dietary adherence has been implicated as an important factor in the success of dieting strategies; however, studies assessing and investigating its association with weight loss success are scarce.We aimed to document the level of dietary adherence using measured diet data and to examine its association with weight loss success.Secondary analysis was performed using data from 181 free-living overweight/obese women (mean+/-s.d. age=43+/-5 years, body mass index=31+/-4 kg m(-2)) participating in a 1-year randomized clinical trial (the A TO Z study) comparing popular weight loss diets (Atkins, Zone and Ornish). Participants' dietary adherence was assessed as the difference between their respective assigned diet's recommended macronutrient goals and their self-reported intake. Association between dietary adherence and 12-month weight change was computed using Spearman's correlations. Differences in baseline characteristics and macronutrient intake between the most and least adherent tertiles for diet groups were compared using t-tests.Within each diet group, adherence score was significantly correlated with 12-month weight change (Atkins, r(s)=0.42, P=0.0003; Zone, r(s)=0.34, P=0.009 and Ornish, r(s)=0.38, P=0.004). Twelve-month weight change in the most vs least adherent tertiles, respectively, was -8.3+/-5.6 vs -1.9+/-5.8 kg, P=0.0006 (Atkins); -3.7+/-6.3 vs -0.4+/-6.8 kg, P=0.12 (Zone) and -6.5+/-6.8 vs -1.7+/-7.9 kg, P=0.06 (Ornish).Regardless of assigned diet groups, 12-month weight change was greater in the most adherent compared to the least adherent tertiles. These results suggest that strategies to increase adherence may deserve more emphasis than the specific macronutrient composition of the weight loss diet itself in supporting successful weight loss.

    View details for DOI 10.1038/ijo.2008.8

    View details for Web of Science ID 000256788500014

    View details for PubMedID 18268511

  • Micronutrient quality of weight loss diets that focus on macronutrients: results from the A TO Z study Gardner, C. D., Kim, S., Morris, J. L., Bersamin, A., Cherin, R. FEDERATION AMER SOC EXP BIOL. 2008
  • Increased water intake reduces metabolic syndrome over 12 mo in overweight dieting women, independent of diet composition, activity and weight loss Stookey, J., Gardner, C., Popkin, B. FEDERATION AMER SOC EXP BIOL. 2008
  • Promoting physical activity through hand-held computer technology AMERICAN JOURNAL OF PREVENTIVE MEDICINE King, A. C., Ahn, D. K., Oliveira, B. M., Atienza, A. A., Castro, C. M., Gardner, C. D. 2008; 34 (2): 138-142


    Efforts to achieve population-wide increases in walking and similar moderate-intensity physical activities potentially can be enhanced through relevant applications of state-of-the-art interactive communication technologies. Yet few systematic efforts to evaluate the efficacy of hand-held computers and similar devices for enhancing physical activity levels have occurred. The purpose of this first-generation study was to evaluate the efficacy of a hand-held computer (i.e., personal digital assistant [PDA]) for increasing moderate intensity or more vigorous (MOD+) physical activity levels over 8 weeks in mid-life and older adults relative to a standard information control arm.Randomized, controlled 8-week experiment. Data were collected in 2005 and analyzed in 2006-2007.Community-based study of 37 healthy, initially underactive adults aged 50 years and older who were randomized and completed the 8-week study (intervention=19, control=18).Participants received an instructional session and a PDA programmed to monitor their physical activity levels twice per day and provide daily and weekly individualized feedback, goal setting, and support. Controls received standard, age-appropriate written physical activity educational materials.Physical activity was assessed via the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire at baseline and 8 weeks.Relative to controls, intervention participants reported significantly greater 8-week mean estimated caloric expenditure levels and minutes per week in MOD+ activity (p<0.04). Satisfaction with the PDA was reasonably high in this largely PDA-naive sample.Results from this first-generation study indicate that hand-held computers may be effective tools for increasing initial physical activity levels among underactive adults.

    View details for DOI 10.1016/j.amepre.2007.09.025

    View details for Web of Science ID 000252758300008

    View details for PubMedID 18201644

    View details for PubMedCentralID PMC2715220

  • Effects of garlic on cholesterol: Not down but not out either - Reply ARCHIVES OF INTERNAL MEDICINE Gardner, C., Lawson, L. D., Block, E. 2008; 168 (1): 112-113
  • Metabolic syndrome: do clinical criteria identify similar individuals among overweight premenopausal women? METABOLISM-CLINICAL AND EXPERIMENTAL Alhassan, S., Kiazand, A., Balise, R. R., King, A. C., Reaven, G. M., Gardner, C. D. 2008; 57 (1): 49-56


    The purpose of this analysis was to determine to what extent the clinical criteria for metabolic syndrome (MetSyn) proposed by the World Health Organization (WHO), the European Group for Study of Insulin Resistance (EGIR), the National Cholesterol Education Program Adult Treatment Panel III (ATP III), and the International Diabetes Foundation (IDF); triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio >/=3.0; and enlarged waist circumference (>/=88 cm) and elevated TG (>/=129 mg/dL) (EWET) identified similar or different overweight women and, secondarily, to examine the effect of 7% weight reduction on MetSyn status. Metabolic syndrome was determined among 256 premenopausal women (age = 41 +/- 6 years, body mass index [BMI] = 32 +/- 4 kg/m(2)) participating in a dietary weight loss clinical trial based on the clinical criteria proposed by WHO, EGIR, ATP III, and IDF. The prevalence of TG/HDL-C ratio >/=3.0 and EWET was determined and compared with MetSyn status. Based on the clinical criteria, 16.1% (EGIR), 20.7% (WHO), 31.0% (ATP III), and 31.8% (IDF) of participants met the criteria for MetSyn; 30.3% and 31.8% had TG/HDL-C >/=3.0 and EWET, respectively. Between 77% and 99% of participants were similarly classified across the clinical criteria. The highest and lowest agreements were between ATP III and IDF (kappa = 0.98; 95% confidence interval, 0.96-1.0) and WHO and IDF (kappa = 0.39; 95% confidence interval, 0.26-0.51), respectively. The TG/HDL-C ratio >/=3.0 and EWET moderately agreed with all 4 clinical criteria for MetSyn (kappa range, 0.36-0.59). Among those diagnosed with MetSyn at baseline, 64.0% to 75.0% of the participants who lost >/=7% and 25.8% to 55.6% of participants who lost <7% of their baseline body weight in 6 months no longer met the various clinical criteria for MetSyn, TG/HDL-C >/=3.0, or EWET. Our findings indicate that MetSyn varies substantially between clinical criteria, which raise questions about the clinical utility of these criteria. Regardless of MetSyn clinical criteria, >/=7% reduction in body weight has a beneficial impact on variables used to define MetSyn.

    View details for DOI 10.1016/j.metabol.2007.08.006

    View details for Web of Science ID 000251929400006

    View details for PubMedID 18078858

    View details for PubMedCentralID PMC2254306

  • Replacing sweetened caloric beverages with drinking water is associated with lower energy intake OBESITY Stookey, J. D., Constant, F., Gardner, C. D., Popkin, B. M. 2007; 15 (12): 3013-3022


    Reduced intake of sweetened caloric beverages (SCBs) is recommended to lower total energy intake. Replacing SCBs with non-caloric diet beverages does not automatically lower energy intake, however. Compensatory increases in other food or beverages reportedly negate benefits of diet beverages. The purpose of this study was to evaluate drinking water as an alternative to SCBs.Secondary analysis of data from the Stanford A TO Z intervention evaluated change in beverage pattern and total energy intake in 118 overweight women (25 to 50 years) who regularly consumed SCBs (>12 ounces/d) at baseline. At baseline and 2, 6, and 12 months, mean daily beverage intake (SCBs, drinking water, non-caloric diet beverages, and nutritious caloric beverages), food composition (macronutrient, water, and fiber content), and total energy intake were estimated using three 24-hour diet recalls. Beverage intake was expressed in relative terms (percentage of beverages).In fixed effects models that controlled for total beverage intake, non-caloric and nutritious caloric beverage intake (percentage of beverages), food composition, and energy expenditure [metabolic equivalent (MET)], replacing SCBs with drinking water was associated with significant decreases in total energy intake that were sustained over time. The caloric deficit attributable to replacing SCBs with water was not negated by compensatory increases in other food or beverages. Replacing all SCBs with drinking water was associated with a predicted mean decrease in total energy of 200 kcal/d over 12 months.The results suggest that replacing SCBs with drinking water can help lower total energy intake in overweight consumers of SCBs motivated to diet.

    View details for Web of Science ID 000252610200018

    View details for PubMedID 18198310

  • Effect of two types of soy milk and dairy milk on plasma lipids in hypercholesterolemic adults: A randomized trial 6th International Symposium of Soy Gardner, C. D., Messina, M., Kiazand, A., Morris, J. L., Franke, A. A. AMER COLLEGE NUTRITION. 2007: 669–77


    To compare the effects of two commercially available soy milks (one made using whole soy beans, the other using soy protein isolate) with low-fat dairy milk on plasma lipid, insulin, and glucose responses.Randomized clinical trial, cross-over design.Participants were 30-65 years of age, n = 28, with pre-study LDL-cholesterol (LDL-C) concentrations of 160-220 mg/dL, not on lipid lowering medications, and with an overall Framingham risk score of or=4 weeks.Mean LDL-C concentration at the end of each phase (+/- SD) was 161 +/- 20, 161 +/- 26 and 170 +/- 24 mg/dL for the whole bean soy milk, the soy protein isolate milk, and the dairy milk, respectively (p = 0.9 between soy milks, p = 0.02 for each soy milk vs. dairy milk). No significant differences by type of milk were observed for HDL-cholesterol, triacylglycerols, insulin, or glucose.A 25 g dose of daily soy protein from soy milk led to a modest 5% lowering of LDL-C relative to dairy milk among adults with elevated LDL-C. The effect did not differ by type of soy milk and neither soy milk significantly affected other lipid variables, insulin or glucose.

    View details for Web of Science ID 000252373200008

    View details for PubMedID 18187432

  • Effect of Ginkgo biloba (EGb 761) aggregation and platelet and aspirin on platelet analysis among older adults at risk of cardiovascular disease: a randomized clinical trial BLOOD COAGULATION & FIBRINOLYSIS Gardner, C. D., Zehnder, J. L., Rigby, A. J., Nicholus, J. R., Farquhar, J. W. 2007; 18 (8): 787-793


    Several case reports have implicated Ginkgo biloba in clinically adverse bleeding disorders. Ginkgo biloba has been reported to increase pain-free walking distance among patients with peripheral artery disease (PAD). Standard PAD therapy includes 325 mg/day aspirin. The objective of this study was to examine potential adverse effects of concomitant aspirin and Ginkgo biloba on platelet function. Ginkgo biloba (EGb 761, 300 mg/day) was compared with placebo for effects on measures of platelet aggregation among adults consuming 325 mg/day aspirin in a randomized, double-blind, placebo-controlled, parallel design trial of 4-week duration. Participants were adults, age 69 +/- 10 years, with PAD or risk factors for cardiovascular disease. Outcome measures included platelet function analysis (PFA-100 analyzer) using ADP as an agonist (n = 26 placebo; n = 29 ginkgo), and platelet aggregation using ADP, epinephrine, collagen and ristocetin as agonists (n = 21 placebo; n = 23 ginkgo). Participants kept daily logs of bleeding or bruising episodes. There were no clinically or statistically significant differences between treatment groups for any agonists, for either PFA-100 analysis or platelet aggregation. Reports of bleeding or bruising were infrequent and similar for both study groups. In conclusion, in older adults with PAD or cardiovascular disease risk, a relatively high dose of Ginkgo biloba combined with 325 mg/day daily aspirin did not have a clinically or statistically detectable impact on indices of coagulation examined over 4 weeks, compared with the effect of aspirin alone. No adverse bleeding events were observed, although the trial was limited to a small sample size.

    View details for Web of Science ID 000251271200012

    View details for PubMedID 17982321

  • Comparison of weight-loss diets - Reply JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Gardner, C. D., Stafford, R. S., King, A. C. 2007; 298 (2): 174–75
  • Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Gardner, C. D., Kiazand, A., Alhassan, S., Kim, S., Stafford, R. S., Balise, R. R., Kraemer, H. C., King, A. C. 2007; 297 (9): 969-977


    Popular diets, particularly those low in carbohydrates, have challenged current recommendations advising a low-fat, high-carbohydrate diet for weight loss. Potential benefits and risks have not been tested adequately.To compare 4 weight-loss diets representing a spectrum of low to high carbohydrate intake for effects on weight loss and related metabolic variables.Twelve-month randomized trial conducted in the United States from February 2003 to October 2005 among 311 free-living, overweight/obese (body mass index, 27-40) nondiabetic, premenopausal women.Participants were randomly assigned to follow the Atkins (n = 77), Zone (n = 79), LEARN (n = 79), or Ornish (n = 76) diets and received weekly instruction for 2 months, then an additional 10-month follow-up.Weight loss at 12 months was the primary outcome. Secondary outcomes included lipid profile (low-density lipoprotein, high-density lipoprotein, and non-high-density lipoprotein cholesterol, and triglyceride levels), percentage of body fat, waist-hip ratio, fasting insulin and glucose levels, and blood pressure. Outcomes were assessed at months 0, 2, 6, and 12. The Tukey studentized range test was used to adjust for multiple testing.Weight loss was greater for women in the Atkins diet group compared with the other diet groups at 12 months, and mean 12-month weight loss was significantly different between the Atkins and Zone diets (P<.05). Mean 12-month weight loss was as follows: Atkins, -4.7 kg (95% confidence interval [CI], -6.3 to -3.1 kg), Zone, -1.6 kg (95% CI, -2.8 to -0.4 kg), LEARN, -2.6 kg (-3.8 to -1.3 kg), and Ornish, -2.2 kg (-3.6 to -0.8 kg). Weight loss was not statistically different among the Zone, LEARN, and Ornish groups. At 12 months, secondary outcomes for the Atkins group were comparable with or more favorable than the other diet groups.In this study, premenopausal overweight and obese women assigned to follow the Atkins diet, which had the lowest carbohydrate intake, lost more weight at 12 months than women assigned to follow the Zone diet, and had experienced comparable or more favorable metabolic effects than those assigned to the Zone, Ornish, or LEARN diets [corrected] While questions remain about long-term effects and mechanisms, a low-carbohydrate, high-protein, high-fat diet may be considered a feasible alternative recommendation for weight Identifier: NCT00079573.

    View details for Web of Science ID 000244697900026

    View details for PubMedID 17341711

  • Effect of raw garlic vs commercial garlic supplements on plasma lipid concentrations in adults with moderate hypercholesterolemia - A randomized clinical trial ARCHIVES OF INTERNAL MEDICINE Gardner, C. D., Lawson, L. D., Chatterjee, L. M., Kiazand, A., Balise, R. R., Kraemer, H. C. 2007; 167 (4): 346-353


    Garlic is widely promoted as a cholesterol-lowering agent, but efficacy studies have produced conflicting results. Garlic supplements differ in bioavailability of key phytochemicals. We evaluated the effect of raw garlic and 2 commonly used garlic supplements on cholesterol concentrations in adults with moderate hypercholesterolemia.In this parallel-design trial, 192 adults with low-density lipoprotein cholesterol (LDL-C) concentrations of 130 to 190 mg/dL (3.36-4.91 mmol/L) were randomly assigned to 1 of the following 4 treatment arms: raw garlic, powdered garlic supplement, aged garlic extract supplement, or placebo. Garlic product doses equivalent to an average-sized garlic clove were consumed 6 d/wk for 6 months. The primary study outcome was LDL-C concentration. Fasting plasma lipid concentrations were assessed monthly. Extensive chemical characterization of study materials was conducted throughout the trial.Retention was 87% to 90% in all 4 treatment arms, and chemical stability of study materials was high throughout the trial. There were no statistically significant effects of the 3 forms of garlic on LDL-C concentrations. The 6-month mean (SD) changes in LDL-C concentrations were +0.4 (19.3) mg/dL (+0.01 [0.50] mmol/L), +3.2 (17.2) mg/dL (+0.08 [0.44] mmol/L), +0.2 (17.8) mg/dL (+0.005 [0.46] mmol/L), and -3.9 (16.5) mg/dL (-0.10 [0.43] mmol/L) for raw garlic, powdered supplement, aged extract supplement, and placebo, respectively. There were no statistically significant effects on high-density lipoprotein cholesterol, triglyceride levels, or total cholesterol-high-density lipoprotein cholesterol ratio.None of the forms of garlic used in this study, including raw garlic, when given at an approximate dose of a 4-g clove per day, 6 d/wk for 6 months, had statistically or clinically significant effects on LDL-C or other plasma lipid concentrations in adults with moderate hypercholesterolemia.

    View details for Web of Science ID 000244467000009

    View details for PubMedID 17325296

  • A proposed method for assessing plasma hypertonicity in vivo EUROPEAN JOURNAL OF CLINICAL NUTRITION Stookey, J. D., Burg, M., Sellmeyer, D. E., Greenleaf, J. E., Arieff, A., Van Hove, L., Gardner, C., King, J. C. 2007; 61 (1): 143-146


    Indices of plasma hypertonicity, elevated plasma concentrations of solutes that draw fluid out of cells by osmosis, are needed to pursue hypertonicity as a possible risk factor for obesity and chronic disease. This paper proposes a new index that may be more sensitive to mild hypertonicity in vivo at a point in time than traditional measures. The index compares mean corpuscular volume (MCV) estimates from diluted (in solution by automated cell counter) and nondiluted blood (calculated from manual hematocrit, MCV=Hct/RBC*10(6)). A larger Auto vs Manual MCV (>2 fl) in vitro indicates hypertonicity in vivo if the cell counter diluent is isotonic with the threshold for plasma vasopressin (PVP) release and PVP is detectable in plasma (>0.5 pg/ml). To evaluate this principle of concept, hypertonicity was induced by 24-h fluid restriction after a 20 ml/kg water load in four healthy men (20-46 years). Unlike serum and urine indices, the MCV difference-&-PVP index detected hypertonicity in all participants.

    View details for DOI 10.1038/sj.ejcn.1602481

    View details for Web of Science ID 000242830700022

    View details for PubMedID 16855542

  • Metabolic syndrome: Does definition determine prevalence? Alhassan, S., Kiazand, A., Balise, R. R., Stafford, R. S., King, A. C., Gardner, C. D. LIPPINCOTT WILLIAMS & WILKINS. 2006: 873
  • Modest 1-year changes in weight and percent body fat among overweight women assigned to Atkins, Zone, Ornish, or LEARN diets Gardner, C. D., Morris, J. L., Kim, S. W., Kiazand, A., Alhassan, S., King, A. LIPPINCOTT WILLIAMS & WILKINS. 2006: E305
  • Dietary antioxidant did not influence flow-mediated vasodilation in adults at risk of atherosclerosis Kiazand, A., Gardner, C. D., Fair, J. M., Mahbouba, M. H. LIPPINCOTT WILLIAMS & WILKINS. 2006: E371-E372
  • No effect of 3 forms of garlic on plasma lipids: A randomized clinical trial Gardner, C. D., Lawson, L., Chatterjee, L. M., Kiazand, A., Block, E. LIPPINCOTT WILLIAMS & WILKINS. 2006: E373
  • Composition, stability, and bioavailability of garlic products used in a clinical trial JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY Lawson, L. D., Gardner, C. D. 2005; 53 (16): 6254-6261


    In support of a new clinical trial designed to compare the effects of crushed fresh garlic and two types of garlic supplement tablets (enteric-coated dried fresh garlic and dried aged garlic extract) on serum lipids, the three garlic products have been characterized for (a) composition (14 sulfur and 2 non-sulfur compounds), (b) stability of suspected active compounds, and (c) availability of allyl thiosulfinates (mainly allicin) under both simulated gastrointestinal (tablet dissolution) conditions and in vivo. The allyl thiosulfinates of blended fresh garlic were stable for at least 2 years when stored at -80 degrees C. The dissolution release of thiosulfinates from the enteric-coated garlic tablets was found to be >95%. The bioavailability of allyl thiosulfinates from these tablets, measured as breath allyl methyl sulfide, was found to be complete and equivalent to that of crushed fresh garlic. S-Allylcysteine was stable for 12 months at ambient temperature. The stability of the suspected active compounds under the conditions of the study and the bioavailability of allyl thiosulfinates from the dried garlic supplement have validated the use of these preparations for comparison in a clinical trial.

    View details for DOI 10.1021/jf050536+

    View details for Web of Science ID 000231047100013

    View details for PubMedID 16076102

    View details for PubMedCentralID PMC2584604

  • The effect of a plant-based diet on plasma lipids in hypercholesterolemic adults - A randomized trial ANNALS OF INTERNAL MEDICINE Gardner, C. D., Coulston, A., Chatterjee, L., Rigby, A., Spiller, G., Farquhar, J. W. 2005; 142 (9): 725-733


    A variety of food combinations can be used to meet national U.S. guidelines for obtaining 30% of energy or less from total fat and 10% of energy or less from saturated fat.To contrast plasma lipid responses to 2 low-fat diet patterns.Randomized clinical trial.4-week outpatient feeding study with weight held constant.120 adults 30 to 65 years of age with prestudy low-density lipoprotein (LDL) cholesterol concentrations of 3.3 to 4.8 mmol/L (130 to 190 mg/dL), body mass index less than 31 kg/m2, estimated dietary saturated fat at least 10% of calories, and otherwise general good health.Plasma lipid levels.Two diets, the Low-Fat diet and the Low-Fat Plus diet, designed to be identical in total fat, saturated fat, protein, carbohydrate, and cholesterol content, consistent with former American Heart Association Step I guidelines. The Low-Fat diet was relatively typical of a low-fat U.S. diet. The Low-Fat Plus diet incorporated considerably more vegetables, legumes, and whole grains, consistent with the 2000 American Heart Association revised guidelines.Four-week changes in the Low-Fat and Low-Fat Plus groups were -0.24 mmol/L (-9.2 mg/dL) versus -0.46 mmol/L (-17.6 mg/dL) for total cholesterol (P = 0.01) and -0.18 mmol/L (-7.0 mg/dL) versus -0.36 mmol/L (-13.8 mg/dL) for LDL cholesterol (P = 0.02); between-group differences were -0.22 mmol/L (-9 mg/dL) (95% CI, -0.05 to -0.39 mmol/L [-2 to -15 mg/dL]) and -0.18 mmol/L (-7 mg/dL) (CI, -0.04 to -0.32 mmol/L [-2 to -12 mg/dL]) for total and LDL cholesterol, respectively. The 2 diet groups did not differ significantly in high-density lipoprotein cholesterol and triglyceride levels.4-week duration.Previous national dietary guidelines primarily emphasized avoiding saturated fat and cholesterol; as a result, the guidelines probably underestimated the potential LDL cholesterol-lowering effect of diet. In this study, emphasis on including nutrient-dense plant-based foods, consistent with recently revised national guidelines, increased the total and LDL cholesterol-lowering effect of a low-fat diet.

    View details for Web of Science ID 000228825800001

    View details for PubMedID 15867404

  • Soy, garlic, and ginkgo biloba: their potential role in cardiovascular disease prevention and treatment. Current atherosclerosis reports Gardner, C. D., Messina, M., Lawson, L. D., Farquhar, J. W. 2003; 5 (6): 468-475


    There are hundreds of foods, nutrients, herbs, and botanicals that have "bioactive" constituents with potential human health benefits. Three of these are discussed in this review: soy, garlic, and ginkgo biloba. Each of these three choices involves an ingestible item composed of a complex mixture of bioactive agents. For each of these three, there is a large and growing body of research suggesting potential cardiovascular health benefits. And for each there is at least some level of disagreement or controversy. The focus of this review is on results from recent human clinical trials.

    View details for PubMedID 14525680

  • Efficacy and safety of low-carbohydrate diets - A systematic review JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Bravata, D. M., Sanders, L., Huang, J., Krumholz, H. M., Olkin, I., Gardner, C. D., Bravata, D. M. 2003; 289 (14): 1837-1850


    Low-carbohydrate diets have been popularized without detailed evidence of their efficacy or safety. The literature has no clear consensus as to what amount of carbohydrates per day constitutes a low-carbohydrate diet.To evaluate changes in weight, serum lipids, fasting serum glucose, and fasting serum insulin levels, and blood pressure among adults using low-carbohydrate diets in the outpatient setting.We performed MEDLINE and bibliographic searches for English-language studies published between January 1, 1966, and February 15, 2003, with key words such as low carbohydrate, ketogenic, and diet.We included articles describing adult, outpatient recipients of low-carbohydrate diets of 4 days or more in duration and 500 kcal/d or more, and which reported both carbohydrate content and total calories consumed. Literature searches identified 2609 potentially relevant articles of low-carbohydrate diets. We included 107 articles describing 94 dietary interventions reporting data for 3268 participants; 663 participants received diets of 60 g/d or less of carbohydrates--of whom only 71 received 20 g/d or less of carbohydrates. Study variables (eg, number of participants, design of dietary evaluation), participant variables (eg, age, sex, baseline weight, fasting serum glucose level), diet variables (eg, carbohydrate content, caloric content, duration) were abstracted from each study.Two authors independently reviewed articles meeting inclusion criteria and abstracted data onto pretested abstraction forms.The included studies were highly heterogeneous with respect to design, carbohydrate content (range, 0-901 g/d), total caloric content (range, 525-4629 kcal/d), diet duration (range, 4-365 days), and participant characteristics (eg, baseline weight range, 57-217 kg). No study evaluated diets of 60 g/d or less of carbohydrates in participants with a mean age older than 53.1 years. Only 5 studies (nonrandomized and no comparison groups) evaluated these diets for more than 90 days. Among obese patients, weight loss was associated with longer diet duration (P =.002), restriction of calorie intake (P =.03), but not with reduced carbohydrate content (P =.90). Low-carbohydrate diets had no significant adverse effect on serum lipid, fasting serum glucose, and fasting serum insulin levels, or blood pressure.There is insufficient evidence to make recommendations for or against the use of low-carbohydrate diets, particularly among participants older than age 50 years, for use longer than 90 days, or for diets of 20 g/d or less of carbohydrates. Among the published studies, participant weight loss while using low-carbohydrate diets was principally associated with decreased caloric intake and increased diet duration but not with reduced carbohydrate content.

    View details for PubMedID 12684364

  • Plant-based food intake and cardiovascular disease (CVD) risk factor status in a national sample of ethnically diverse women (NHANES III) Experimental Biology 2003 Annual Meeting Carlson, J. J., Winkleby, M., Gardner, C., Ahn, D. FEDERATION AMER SOC EXP BIOL. 2003: A372–A372
  • Recent discoveries in inclusive food-based approaches and dietary patterns for reduction in risk for cardiovascular disease CURRENT OPINION IN LIPIDOLOGY Kris-Etherton, P. M., Etherton, T. D., Carlson, J., Gardner, C. 2002; 13 (4): 397-407


    To discuss new evidence-based dietary recommendations founded on an inclusive food strategy and to address the challenges that are posed by integrating a growing list of heart healthy foods into the diet without increasing energy intake beyond that required to achieve a healthy body weight.New food-based dietary recommendations issued by the American Heart Association with the objective of reducing risk for cardiovascular disease (CVD) promote an inclusionary approach. The American Heart Association recommends a variety of foods to target four major goals: achieve a healthy overall diet, achieve a healthy weight, promote desirable lipid levels, and promote desirable blood pressure. Specific foods recommended include fruits and vegetables, grain products (including whole grains), fish, lean meat and poultry, fat-free or low-fat dairy products, and legumes. In addition, the new National Cholesterol Education Program Adult Treatment Panel III recommends reductions in saturated fat and cholesterol and therapeutic dietary options for enhancing LDL-cholesterol lowering, with inclusion of plant stanols/sterols (2 g/day) and increased viscous (soluble) fiber (10-25 g/day). In parallel with the evolution of new dietary recommendations is the expanding list of specific foods that have cardioprotective effects. Additional foods on this list are nuts, soy, legumes, alcohol, tea, and garlic.It will be challenging to include all foods that reduce CVD risk in the diet and still maintain energy control. Strategies are needed that facilitate developing heart healthy dietary patterns that maximally reduce CVD risk.

    View details for Web of Science ID 000177360400007

    View details for PubMedID 12151855

  • Low-carbohydrate diets: A systematic review of their safety and efficacy. Bravata, D. M., Sanders, L., Huang, J., Krumholz, H. M., Olkin, I., Gardner, C., Bravata, D. SPRINGER. 2002: 185–185
  • Plant-based food intake and nutrient and phytochemical status in a national sample of ethnically diverse women (NHANES III) Carlson, J., Ahn, D., Winkleby, M., Gardner, C. FEDERATION AMER SOC EXP BIOL. 2002: A228–A228
  • Gaining insight into the health effects of soy but a long way still to go: Commentary on the Fourth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease 4th International Symposium on the Role of Soy in Preventing and Treating Chronic Disease Messina, M., Gardner, C., Barnes, S. AMER SOC NUTRITIONAL SCIENCE. 2002: 547S–551S


    Research into the health effects of soyfoods and soybean constituents has increased at a phenomenal pace over the past decade. This research includes a wide range of areas, such as cancer, coronary heart disease, osteoporosis, cognitive function, menopausal symptoms and renal function. Importantly, there are an increasing number of clinical studies being conducted in this field, which was quite evident from the findings presented at the Fourth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease, November 4-7, 2001, in San Diego, California. There is no doubt that progress in understanding the health effects of soy is being made, but much of the data are frustratingly inconsistent. For example, there were conflicting results presented at the symposium on the role of isoflavones in bone health. Similarly, presentations painted an unclear picture of the role of isoflavones in cholesterol reduction. The relatively short duration and small sample size of many of the human studies in this field likely contribute to the inconsistent results. Although there are some controversies regarding the safety of soy for certain subsets of the population, special sessions at the symposium on breast cancer and cognitive function did much to alleviate concerns that soy could have detrimental effects in these areas. Furthermore, published data and new research presented at this meeting suggest that the consumption of even 10 g (typical of Asian intake) of isoflavone-rich soy protein per day may be associated with health benefits. If this modest amount of soy protein were to be incorporated in the American diet, it would represent only approximately 15% of total U. S. protein intake.

    View details for Web of Science ID 000174189800042

    View details for PubMedID 11880591

  • The role of plant-based diets in the treatment and prevention of coronary artery disease CORONARY ARTERY DISEASE Gardner, C. D. 2001; 12 (7): 553-559

    View details for Web of Science ID 000172322600005

    View details for PubMedID 11714995

  • The effect of soy protein with or without isoflavones relative to milk protein on plasma lipids in hypercholesterolemic postmenopausal women AMERICAN JOURNAL OF CLINICAL NUTRITION Gardner, C. D., Newell, K. A., Cherin, R., Haskell, W. L. 2001; 73 (4): 728-735


    Clinical trial data and the results of a meta-analysis suggest a hypocholesterolemic effect of soy protein. The effect may be partially attributable to the isoflavones in soy. Few studies have examined the separate effects of soy protein and isoflavones.The objective of this study was to determine the effect of soy protein and isoflavones on plasma lipid concentrations in postmenopausal, moderately hypercholesterolemic women.This was a randomized, double-blind, placebo-controlled clinical trial with 3 treatment groups. After a 4-wk run-in phase during which the women consumed a milk protein supplement, the subjects were randomly assigned to 12 wk of dietary protein supplementation (42 g/d) with either a milk protein (Milk group) or 1 of 2 soy proteins containing either trace amounts of isoflavones (Soy- group) or 80 mg aglycone isoflavones (Soy+ group).LDL-cholesterol concentrations decreased more in the Soy+ group (n = 31) than in the Soy- group (n = 33) (0.38 compared with 0.09 mmol/L; P = 0.005), but neither of these changes was significantly different from the 0.26-mmol/L decrease observed in the Milk group (n = 30). The results for total cholesterol were similar to those for LDL cholesterol. There were no significant differences in HDL-cholesterol or triacylglycerol concentrations between the 3 groups.The difference in total- and LDL-cholesterol lowering between the 2 soy-protein supplements suggests an effect attributable to the isoflavone-containing fraction. However, the unexpected LDL-cholesterol lowering observed in the Milk group, and the fact that there was no significant difference between either soy group and the Milk group, suggests that changes may have been due to other factors related to participation in the study.

    View details for Web of Science ID 000167716200010

    View details for PubMedID 11273847

  • Garlic shows promise for improving some cardiovascular risk factors Evidence-based Complementary Medicine Congress Ackermann, R. T., Mulrow, C. D., Ramirez, G., Gardner, C. D., Morbidoni, L., Lawrence, V. A. AMER MEDICAL ASSOC. 2001: 813–24


    To summarize the effects of garlic on several cardiovascular-related factors and to note its adverse effects.English and non-English citations were identified from 11 electronic databases, references, manufacturers, and experts from January 1966 through February 2000 (depending on the database searched). Reports of cardiovascular-related effects were limited to randomized controlled trials lasting at least 4 weeks. Reports of adverse effects were not limited by study design. From 1798 pertinent records, 45 randomized trials and 73 additional studies reporting adverse events were identified. Two physicians abstracted outcomes and assessed adequacy of randomization, blinding, and handling of dropouts. Standardized mean differences of lipid outcomes from placebo-controlled trials were adjusted for baseline differences and pooled using random effects methods.Compared with placebo, garlic preparations may lead to small reductions in the total cholesterol level at 1 month (range of average pooled reductions, 0.03-0.45 mmol/L [1.2-17.3 mg/dL]) and at 3 months (range of average pooled reductions 0.32-0.66 mmol/L [12.4-25.4 mg/dL]), but not at 6 months. Changes in low-density lipoprotein levels and triglyceride levels paralleled total cholesterol level results; no statistically significant changes in high-density lipoprotein levels were observed. Trials also reported significant reductions in platelet aggregation and mixed effects on blood pressure outcomes. No effects on glycemic-related outcomes were found. Proven adverse effects included malodorous breath and body odor. Other unproven effects included flatulence, esophageal and abdominal pain, allergic reactions, and bleeding.Trials suggest possible small short-term benefits of garlic on some lipid and antiplatelet factors, insignificant effects on blood pressure, and no effect on glucose levels. Conclusions regarding clinical significance are limited by the marginal quality and short duration of many trials and by the unpredictable release and inadequate definition of active constituents in study preparations.

    View details for Web of Science ID 000167611200003

    View details for PubMedID 11268223

  • The effect of a garlic preparation on plasma lipid levels in moderately hypercholesterolemic adults ATHEROSCLEROSIS Gardner, C. D., Chatterjee, L. M., Carlson, J. J. 2001; 154 (1): 213-220


    Lipid management is well established as an effective preventive and management tool for cardiovascular disease (CVD). Health claims regarding the cholesterol lowering benefits of garlic are widespread. However, the clinical trial data are inconsistent. The effect of two doses of a commercial garlic preparation on plasma lipids were evaluated, compared to a placebo, in moderately hypercholesterolemic adults (baseline low density lipoprotein cholesterol (LDL-C)=157. 4+/-18.7, mean+/-S.D.). Fifty-one adults, aged 51.8+/-8.3 years participated in a double-blind, placebo-controlled, parallel treatment trial conducted in an outpatient research clinic. They were randomized to a placebo or a garlic botanical blend providing 500 or 1000 mg dehydrated garlic powder/day (three groups, 16-18 subjects per group). Plasma lipids were assessed every 2 weeks for 12 weeks. The study was designed with sufficient power to detect a 10% relative decline in LDL-C. The absolute mean changes in LDL-C over 12 weeks were 0.0+/-4.3, +1.4+/-4.8, and -10.1+/-6.8 mg/dl for the placebo, half-dose and full-dose, respectively. In the full-dose group, the LDL-C decrease of 6.1% was not significantly different from the other groups (P=0.5). No significant differences were observed for total- or high-density lipoprotein cholesterol (HDL-C), or triacylglycerol levels. In conclusion, the garlic powder preparation used in this study among moderately hypercholesterolemic adults did not significantly effect plasma lipids levels. There was no indication of a graded affect by garlic dose over the range of 0, 500 and 1000 mg/day. A small (<10%) effect on LDL-C levels or a threshold effect requiring larger doses are not eliminated by this study.

    View details for Web of Science ID 000166116000026

    View details for PubMedID 11137102

  • Population frequency distributions of HDL, HDL2, and HDL3 cholesterol and apolipoproteins A-I and B in healthy men and women and associations with age, gender, hormonal status, and sex hormone use: The Stanford Five City Project PREVENTIVE MEDICINE Gardner, C. D., Tribble, D. L., Young, D. R., Ahn, D., Fortmann, S. P. 2000; 31 (4): 335-345


    The purpose of this study is to present population-based frequency distribution data for several lipoprotein-related variables and to examine their associations with gender, age, menopausal status, and sex hormone use.High-density lipoprotein cholesterol (HDL-C), HDL(2)-C, HDL(3)-C, apolipoprotein (Apo) A-I, and Apo B were measured in a population-based sample of 1, 027 healthy adults from four California cities who participated in the 1989-1990 survey of the Stanford Five City Project. These data were examined cross-sectionally with sociodemographic and other related variables.Relative to men, all of the HDL-related parameters-HDL-C, HDL(2)-C, HDL(3)-C, Apo A-I-were significantly higher and Apo B levels were significantly lower among women (P < 0. 001). Menopausal status was not associated with HDL-related parameters, but Apo B levels were higher in post- versus premenopausal women (P < 0.001). Among women, HDL-C and Apo A-I levels were higher in oral contraceptive and estrogen replacement therapy users (P = 0.003). Most of the significant findings remained statistically significant after adjusting for age, body mass index, smoking, energy expenditure, and alcohol intake.These population-based data indicate that gender, menopausal status, and the use of sex hormones among women are associated with differential levels of one or more of HDL-C, HDL(2)-C, HDL(3)-C, Apo A-I, and Apo B, independent of age and a broad set of lifestyle factors.

    View details for DOI 10.1006/pmed.2000.0715

    View details for Web of Science ID 000089566300007

    View details for PubMedID 11006058

  • Associations of HDL, HDL2, and HD3 cholesterol and apolipoproteins A-I and B with lifestyle factors in healthy women and men: The Stanford Five City Project PREVENTIVE MEDICINE Gardner, C. D., Tribble, D. L., Young, D. R., Ahn, D., Fortmann, S. P. 2000; 31 (4): 346-356


    Measures of the two major high-density lipoprotein (HDL) subfractions, HDL(2) and HDL(3), and the major apolipoproteins of HDL and low-density lipoprotein (LDL), Apo A-I and Apo B, may be etiologically important factors in the development of coronary artery disease. The association of lifestyle factors with these lipoprotein-related variables remains unclear.HDL-C, HDL(2)-C, HDL(3)-C, Apo A-I, and Apo B levels were determined in a population-based sample of 1,027 healthy women and men aged 25-64 years, from four California cities who participated in the 1989/1990 survey of the Stanford Five City Project. In this cross-sectional study we examined the independent associations of these lipoprotein-related variables with body mass index (BMI), cigarette smoking, daily energy expenditure, alcohol intake, dietary intake, and hormone use (oral contraceptives and estrogen replacement therapy).In general, BMI and alcohol intake were the strongest independent predictors of the lipoprotein-related variables. The negative association of BMI with HDL-C was attributable primarily to the association with the HDL(2)-C subfraction, while for alcohol intake the positive association with HDL-C was attributable primarily to the association with HDL(3)-C, particularly in men. Among men, but not women, energy expenditure was a significant independent predictor of each of the lipoprotein-related variables, with positive associations observed for HDL-C, HDL(2)-C, HDL(2)-C, and Apo A-I and a negative association observed for Apo B (P < 0.005).Data from this population-based sample suggest that specific lifestyle factors are more strongly associated with some lipoprotein-related variables than with others, with notable gender differences.

    View details for DOI 10.1006/pmed.2000.0716

    View details for Web of Science ID 000089566300008

    View details for PubMedID 11006059

  • Population frequency distribution of non-high-density lipoprotein cholesterol (Third National Health and Nutrition Examination Survey [NHANES III], 1998-1994) AMERICAN JOURNAL OF CARDIOLOGY Gardner, C. D., Winkleby, M. A., Fortmann, S. P. 2000; 86 (3): 299-304


    The objective of this study was to provide population frequency distribution data for non-high-density lipoprotein (HDL) cholesterol (total cholesterol minus HDL cholesterol) concentrations and to evaluate whether differences exist by gender, ethnicity, or level of education. Serum levels of non-HDL cholesterol and sociodemographic characteristics were determined for 3,618 black, 3,528 Mexican-American, and 6,043 white women and men, aged >/=25 years, from a national cross-sectional survey of the US population (National Health And Nutrition Examination Survey III, 1988-1994). Age-adjusted non-HDL cholesterol concentrations were lower in women than men (154.1 vs 160.4 mg/dL, p <0.001). In women and men, age was positively associated with non-HDL cholesterol in the 25 to 64-year age range, and the slope of the association was steeper for women. For women and men >/=65 years, age was negatively associated with non-HDL cholesterol, and the slope of the association was steeper for men. Black women and men had lower non-HDL cholesterol levels than either Mexican-American or white women and men (women, p <0.02; men, p <0.001, for both ethnic contrasts). Women with less education had higher levels of non-HDL cholesterol than women with more education (p <0.01). These nationally representative population frequency distribution data provide non-HDL cholesterol reference levels for clinicians and investigators and indicate that there are significant variations in non-HDL cholesterol by gender, age, ethnicity, and level of education.

    View details for Web of Science ID 000088423900009

    View details for PubMedID 10922437

  • Effect of garlic supplementation on plasma lipids in hypercholesterolemic men and women Gardner, C. D., Chatterjee, L., Carlson, J. LIPPINCOTT WILLIAMS & WILKINS. 1999: 1123
  • Effect of soy protein and phytoestrogen intake on plasma lipids in hypercholesterolemic postmenopausal women Gardner, C. D., Newell, K. A., Haskell, W. L. LIPPINCOTT WILLIAMS & WILKINS. 1999: 1107
  • Clinical review 97 - Potential health benefits of dietary phytoestrogens: A review of the clinical, epidemiological, and mechanistic evidence JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Tham, D. M., Gardner, C. D., Haskell, W. L. 1998; 83 (7): 2223-2235


    Phytoestrogens represent a family of plant compounds that have been shown to have both estrogenic and antiestrogenic properties. A variety of these plant compounds and their mammalian metabolic products have been identified in various human body fluids and fall under two main categories: isoflavones and lignans. A wide range of commonly consumed foods contain appreciable amounts of these different phytoestrogens. For example, soy and flax products are particularly good sources of isoflavones and lignans, respectively. Accumulating evidence from molecular and cellular biology experiments, animal studies, and, to a limited extent, human clinical trials suggests that phytoestrogens may potentially confer health benefits related to cardiovascular diseases, cancer, osteoporosis, and menopausal symptoms. These potential health benefits are consistent with the epidemiological evidence that rates of heart disease, various cancers, osteoporotic fractures, and menopausal symptoms are more favorable among populations that consume plant-based diets, particularly among cultures with diets that are traditionally high in soy products. The evidence reviewed here will facilitate the identification of what is known in this area, the gaps that exist, and the future research that holds the most potential and promise.

    View details for Web of Science ID 000074562200001

    View details for PubMedID 9661587

  • Advantages of excluding underpowered studies in meta-analysis: Inclusionist versus exclusionist viewpoints PSYCHOLOGICAL METHODS Kraemer, H. C., Gardner, C., Brooks, J. O., Yesavage, J. A. 1998; 3 (1): 23-31
  • Association of small low-density lipoprotein particles with the incidence of coronary artery disease in men and women JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Gardner, C. D., Fortmann, S. P., Krauss, R. M. 1996; 276 (11): 875-881


    To investigate the prospective association of low-density lipoprotein (LDL) particle diameter with the incidence of fatal and nonfatal coronary artery disease (CAD).A nested case-control study.Cases and controls were identified from a population-based sample of men and women combining all of the 5 cross-sectional surveys conducted from 1979 to 1990 of the Stanford Five-City Project (FCP).Incident CAD cases were identified through FCP surveillance between 1979 and 1992. Controls were matched by sex, 5-year age groups, survey time point, ethnicity, and FCP treatment condition. The sample included 124 matched pairs: 90 pairs of men and 34 pairs of women.LDL peak particle diameter (LDL size) was determined by gradient gel electrophoresis on plasma samples collected during the cross-sectional surveys (stored at 70 degrees C for 5-15 years). Established CAD risk-factor data were available from FCP baseline measurements.LDL size was smaller among CAD cases than controls (mean +/- SD) (26.17 +/- 1.00 nm vs 26.68 +/- 0.90 nm; P<.001). The association was graded across control quintiles of LDL size. The significant case-control difference in LDL size was independent of levels of high-density lipoprotein cholesterol (HDL-C), non-HDL cholesterol (non-HDL-C), triglyceride, smoking, systolic blood pressure, and body mass index, but was not significant after adjusting for the ratio of total cholesterol (TC) to HDL-C (TC:HDL-C). Among all the physiological risk factors, LDL size was the best differentiator of CAD status in conditional logistic regression. However, when added to the physiological parameters above, the TC:HDL-C ratio was found to be a stronger independent predictor of CAD status.LDL size was significantly smaller in CAD cases than in controls in a prospective, population-based study. These findings support other evidence of a role for small, dense LDL particles in the etiology of atherosclerosis.

    View details for Web of Science ID A1996VF78700030

    View details for PubMedID 8782636

  • Influence of gender and socioeconomic factors on Hispanic/white differences in body mass index PREVENTIVE MEDICINE Winkleby, M. A., Gardner, C. D., Taylor, C. B. 1996; 25 (2): 203-211


    This article examines the effects of gender and socioeconomic factors on ethnic differences in body mass index (BMI) using a matched-pairs design of 688 pairs of Hispanics (principally Mexican American) and whites. Subjects, ages 25-74, were drawn from five population-based surveys conducted from 1979 to 1990 in four northern California cities.Hispanic women and men both had significantly higher BMI levels than the white women and men with whom they were matched (P < 0.001). These ethnic differences persisted across every level of education for both women and men, with the magnitude of the difference ranging from 0.9 BMI units (between the most educated Hispanic and white men) to 2.9 BMI units (between the least educated Hispanic and white women). The highest prevalence of overweight was among the least educated Hispanic women (61.1%) and Hispanic men (48.4%). The higher BMI levels of Hispanic women and men relative to their white counterparts were not explained by age, gender, education, city of residence, time of survey, or language spoken in a multiple regression model. Hispanic women and men both reported higher desired body weight (height standardized) than white women and men, indicating a possible contribution of cultural factors to the ethnic differences in overweight.These findings provide insight into the greater prevalence of overweight in Hispanic relative to white populations as well as guidance for weight-loss interventions tailored to low socioeconomic groups.

    View details for Web of Science ID A1996UK03800015

    View details for PubMedID 8860286



    The objective of this study was to examine whether oils high in monounsaturated or polyunsaturated fats have a differential effect on serum lipid levels, using a meta-analytical approach. Fourteen studies (1983 through 1994) were identified that met six inclusion criteria, the primary criterion being that a study have at least two intervention diets that varied in monounsaturated and polyunsaturated fat content but were otherwise similar in total fat, saturated fat, fiber, and dietary cholesterol. Seven studies included a comparable high-saturated fat diet. Standardized effect sizes observed treatment difference in mean end-point lipid levels, divided by the pooled (SD) were calculated for individual studies, then individual effect sizes were pooled. The results indicated no significant differences in total, LDL, or HDL cholesterol levels when oils high in monounsaturated or polyunsaturated fats were compared directly. Triglyceride levels were modestly but consistently lower on the diets high in polyunsaturated fats (P = .05). Replacement of saturated fat with either monounsaturated or polyunsaturated fat led to significant decreases in total and LDL cholesterol (P < .001), and the pooled effect sizes were comparable for either type of unsaturate (effect sizes ranged from -0.64 to -0.68, ie, roughly a decrease of 0.65 mmol/L [25 mg/dL] relative to the high-saturated fat diets). Neither type of unsaturated fat significantly changed HDL cholesterol or triglyceride levels relative to the high-saturated fat diets. In conclusion, the evidence from this meta-analysis strongly indicates there is no significant difference in LDL or HDL cholesterol levels when oils high in either monounsaturated or polyunsaturated fats are exchanged in the diet. Any dietary recommendations for the use of one in preference to the other should be based on outcomes other than serum cholesterol levels.

    View details for Web of Science ID A1995TE62500016

    View details for PubMedID 7583572