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.
The Rehnborg Farquhar Professorship, Stanford University School of Medicine (2017 - Present)
Director, Clinical and Translational Core, Stanford Diabetes Research Center (2017 - 2022)
Member, American Diabetes Association Dietary Guidelines Committee (2017 - 2019)
Scientific Advisory Committee, Culinary Institute of America (2012 - Present)
Nutrition Committee, American Heart Association (2009 - 2013)
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)
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. In 2013 we are just finishing one trial investigating the effects of antioxidants on inflammatory markers in ~80 adults with metabolic syndrome. In 2013 we are also near to completing another study that is a weight loss trial among 60 overweight and obese adults that were assigned to either a very low carbohydrate vs. a very low fat diet (both of them emphasizing and maximizing nutritional quality) after being stratified by their insulin resistance status. In that trial we are investigating the possibility that certain individuals are predisposed to be more successful with a particular diet (in this case low-carb or low-fat) based on their insulin resistance status. We were recently funded by NIH to conduct a 5-year low-carb vs. low-fat weight loss study among 400 overweight and obese adults after genotyping them and trying to assign them to a diet that we believe they are more vs. less likely to succeed on. Again, in this case we are trying to find characteristics that would help determine differential response to weight loss diets.
In the past few years my long-term research interests have shifted to include a second line of inquiry that falls more under the umbrella of Community Based Participatory Research (CBPR). This shift came from the recent realization and appreciation that focusing on "health" as a motivator for changing and improving human food behaviors can drastically limit the potential impact for change. This realization led me to initiate the first annual Stanford Food Summit in 2010, and now continue that in 2011 and 2012. The first Stanford Food Summit in 2010 was attended by hundreds of scholars from across all seven of Stanford's undergraduate and graduate schools (Medicine, Earth Sciences, Humanities and Sciences, Engineering, Law, Business and Education). The subsequent two Stanford Food Summit (2011 and 2012) have provided forums to present the work and findings of several new community-academic partnerships (e.g., Full Circle Farm in Sunnyvale, CA, and Second Harvest Food Bank in San Mateo and Santa Clara counties) that have been formed through CBPR pilot project funding we were able to provide due to several generous donors who attended our Food Summits and were inspired by our vision for solution-oriented approaches to food system problems. My long-term vision in this area is to create a world-class Stanford Center for Education and Research in Food Systems, 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.
SWAP-MEAT: Study With Appetizing Plant Food - Meat Eating Alternatives Trial
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.
Adding Sleep Intervention to Traditional Diet and Exercise Approach to Weight Loss
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.
Comparing Effects of 3 Sources of Garlic on Cholesterol Levels
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.
Comparison of Popular Weight Loss Diets
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.
DIETFITS Study (Diet Intervention Examining the Factors Interacting With Treatment Success
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.
Effect of Fish Oil on Plasma Triglycerides in Adults
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.
Effects of Dietary Antioxidants on Cardiovascular Risk Factors
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.
Effects of Glutathione (an Antioxidant) and N-Acetylcysteine on Inflammation
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.
Effects of Omega-3 Fatty Acids on Markers of Inflammation
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.
Effects of Raw Versus Other Milk Sources on Lactose Digestion
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.
Effects of Soy Compounds on Breast Cancer, Prostate Cancer, and Bone Health
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.
The RAMP Study - Rejuvenation of the Aging Microbiota With Prebiotics
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.
Weight Loss Diet Study: Low Carb vs Low Fat
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.
- Food and Society: Exploring Eating Behaviors in Social, Environmental, and Policy Context
CHPR 166, HUMBIO 166 (Win)
- Human Nutrition
CHPR 130, HUMBIO 130 (Spr)
Independent Studies (13)
- Community Health and Prevention Research Master's Thesis Writing
CHPR 399 (Aut, Win, Spr)
- Curricular Practical Training and Internship
CHPR 299 (Aut, Win, Spr)
- Directed Individual Study in Earth Systems
EARTHSYS 297 (Win, Spr)
- Directed Reading
CHPR 298 (Aut, Win, Spr, Sum)
- Directed Reading in Medicine
MED 299 (Aut, Win, Spr, Sum)
- Directed Reading/Special Projects
HUMBIO 199 (Aut, Win, Spr)
- Directed Research
EARTHSYS 250 (Win, Spr)
- Early Clinical Experience in Medicine
MED 280 (Aut, Win, Spr, Sum)
- Graduate Research
MED 399 (Aut, Win, Spr, Sum)
HUMBIO 194 (Aut, Win, Spr)
- Medical Scholars Research
MED 370 (Aut, Win, Spr, Sum)
- Research in Human Biology
HUMBIO 193 (Aut, Win, Spr)
- Undergraduate Research
MED 199 (Aut, Win, Spr, Sum)
- Community Health and Prevention Research Master's Thesis Writing
Prior Year Courses
- Healthy/Sustainable Food Systems: Maximum Sustainability across Health, Economics, and Environment
CHPR 113, HUMBIO 113S (Win)
- Human Nutrition
CHPR 130, HUMBIO 130 (Spr)
- Service Learning Practicum
EDUC 98 (Win)
- Food and Society: Exploring Eating Behaviors in Social, Environmental, and Policy Context
CHPR 166, HUMBIO 166 (Win)
- Human Nutrition
CHPR 130, HUMBIO 130 (Spr)
- ASB The Cuisine of Change: Promoting Child Health and Combating Food Insecurity
MED 23 (Win)
- From Foodies to Freegans: Food Popular Topics in the Silicon Valley
MED 158A (Aut)
- Healthy/Sustainable Food Systems: Maximum Sustainability across Health, Economics, and Environment
CHPR 213, HUMBIO 113S (Win)
- Human Nutrition
HUMBIO 130 (Spr)
- Healthy/Sustainable Food Systems: Maximum Sustainability across Health, Economics, and Environment
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
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 whom.clinicaltrials.gov Identifier: NCT01826591.
View details for DOI 10.1001/jama.2018.0245
View details for Web of Science ID 000425508400017
View details for PubMedID 29466592
View details for PubMedCentralID PMC5839290
Sources of Sodium in US Adults From 3 Geographic Regions
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: http://www.clinicaltrials.gov. 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
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
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
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
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
- Weight loss on low-fat vs. low-carbohydrate diets by insulin resistance status among overweight adults and adults with obesity: A randomized pilot trial OBESITY 2016; 24 (1): 79-86
Food-and-beverage environment and procurement policies for healthier work environments
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
Incorporating Prototyping and Iteration Into Intervention Development: A Case Study of a Dining Hall-Based Intervention
JOURNAL OF AMERICAN COLLEGE HEALTH
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
- Nonnutritive Sweeteners: Current Use and Health Perspectives A Scientific Statement From the American Heart Association and the American Diabetes Association CIRCULATION 2012; 126 (4): 509-519
Tailoring dietary approaches for weight loss
Stanford Obesity Summit
View details for DOI 10.1038/ijosup.2012.4
Effects of a College Course About Food and Society on Students' Eating Behaviors
AMERICAN JOURNAL OF PREVENTIVE MEDICINE
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
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
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 loss.clinicaltrials.gov 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
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
The effect of a plant-based diet on plasma lipids in hypercholesterolemic adults - A randomized trial
ANNALS OF INTERNAL MEDICINE
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
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.
The American journal of clinical nutrition
Background: For low-carbohydrate diets, a public health approach has focused on the replacement of carbohydrates with unsaturated fats. However, little research exists on the impacts of saturated fat intake on the lipid profile in the context of whole-food-based low-carbohydrate weight-loss diets.Objectives: The primary aim of this secondary analysis of the DIETFITS weight loss trial was to evaluate the associations between changes in percentage of dietary saturated fatty acid intake (%SFA) and changes in low-density lipoproteins, high-density lipoproteins, and triglyceride concentrations for those following a healthy low-carbohydrate (HLC) diet. The secondary aim was to examine these associations specifically for HLC dieters who had the highest 12-month increases in %SFA.Methods: In the DIETFITS trial, 609 generally healthy adults, aged 18-50 years, with body mass indices of 28-40 kg/m2 were randomly assigned to a healthy low-fat (HLF) or HLC diet for 12 months. In this analysis, linear regression, both without and with adjustment for potential confounders, was used to measure the association between 12-month change in %SFA and blood lipids in 208 HLC participants with complete diet and blood lipid data.Results: Participants consumed an average of 12-18% of calories from SFA. An increase of %SFA, without significant changes in absolute saturated fat intake, over 12 months was associated with a statistically significant decrease in triglycerides in the context of a weight-loss study in which participants simultaneously decreased carbohydrate intake. The association between increase in %SFA and decrease in triglycerides was no longer significant when adjusting for 12-month change in carbohydrate intake, suggesting carbohydrate intake may be a mediator of this relationship.Conclusions: Those on a low-carbohydrate weight-loss diet who increase their percentage intake of dietary saturated fat may improve their overall lipid profile provided they focus on a high-quality diet and lower their intakes of both calories and refined carbohydrates. This trial was registered at clinicaltrials.gov as NCT01826591.
View details for DOI 10.1093/ajcn/nqy305
View details for PubMedID 30649213
- 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 2018
THE EFFECT OF A TEXT MESSAGE-BASED INTERVENTION ON ADHERENCE, WEIGHT LOSS, AND DIET QUALITY
OXFORD UNIV PRESS INC. 2018: S645
View details for Web of Science ID 000431185201722
Antioxidants from diet or supplements do not alter inflammatory markers in adults with cardiovascular disease risk. A pilot randomized controlled trial
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 DOI 10.1016/j.nutres.2017.10.017
View details for Web of Science ID 000428942800007
View details for PubMedID 29540273
View details for PubMedCentralID PMC5858717
- Low-Fat vs Low-Carbohydrate Diets and Weight Loss-Reply. JAMA 2018; 320 (2): 203–4
A systematic review of studies of DNA methylation in the context of a weight loss intervention
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
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
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
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 diseases.ClinicalTrials.gov NCT01826591. Registered 27 March 2013.
View details for DOI 10.1186/s12966-017-0563-2
View details for PubMedID 28915825
View details for PubMedCentralID PMC5603006
Interdisciplinary Food-Related Academic Programs: A 2015 Snapshot of the United States Landscape
Journal of Agriculture, Food Systems, and Community Development
2017; 7 (4)
View details for DOI 10.5304/jafscd.2017.074.006
Iterative development of Vegethon: a theory-based mobile app intervention to increase vegetable consumption
INTERNATIONAL JOURNAL OF BEHAVIORAL NUTRITION AND PHYSICAL ACTIVITY
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 Trials.gov: NCT01826591.
View details for DOI 10.1186/s12966-016-0400-z
View details for Web of Science ID 000381567700001
View details for PubMedID 27501724
Mobile Technology for Vegetable Consumption: A Randomized Controlled Pilot Study in Overweight Adults.
JMIR mHealth and uHealth
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 groups.ClinicalTrials.gov NCT01826591; https://clinicaltrials.gov/ct2/show/NCT01826591 (Archived by WebCite at http://www.webcitation.org/6hYDw2AOB).
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
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 www.clinicaltrials.gov (NCT00901095).
View details for DOI 10.1513/AnnalsATS.201406-271OC
View details for PubMedID 25496399
Effect of Increasing Dietary Fiber on Plasma Levels of Colon-Derived Solutes in Hemodialysis Patients
CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY
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
Ending SNAP Subsidies For Sugar-Sweetened Beverages Could Reduce Obesity And Type 2 Diabetes
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
Digesting Dietary Data
2014; 28 (6): 30-31
View details for Web of Science ID 000336940900007
Effect of raw milk on lactose intolerance: a randomized controlled pilot study.
Annals of family medicine
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
- Effect of Raw Milk on Lactose Intolerance: A Randomized Controlled Pilot Study ANNALS OF FAMILY MEDICINE 2014; 12 (2): 134-141
Non-nutritive sweeteners: evidence for benefit vs. risk
CURRENT OPINION IN LIPIDOLOGY
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
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
Effect of fish oil supplementation on serum triglycerides, LDL cholesterol and LDL subfractions in hypertriglyceridemic adults
NUTRITION METABOLISM AND CARDIOVASCULAR DISEASES
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
Adherence to a low-fat vs. low-carbohydrate diet differs by insulin resistance status
DIABETES OBESITY & METABOLISM
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 2012; 35 (8): 1798-1808
Food Marketing to Children Through Toys Response of Restaurants to the First U.S. Toy Ordinance
AMERICAN JOURNAL OF PREVENTIVE MEDICINE
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
2012; 8 (1): 7-12
View details for DOI 10.1089/chi.2011.0800.rou
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
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
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
Outcome expectations and realizations as predictors of weight regain among dieters
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
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 benefits.clinicaltrials.gov 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
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 2010; 15 (3): 91-92
- The Breathe Easier through Weight Loss Lifestyle (BE WELL) Intervention: A randomized controlled trial BMC PULMONARY MEDICINE 2010; 10
The Breathe Easier through Weight Loss Lifestyle (BE WELL) Intervention: a randomized controlled trial.
BMC pulmonary medicine
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
Prostatic Soy Isoflavone Concentrations Exceed Serum Levels After Dietary Supplementation
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
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
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
Drinking Water Is Associated With Weight Loss in Overweight Dieting Women Independent of Diet and Activity
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
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
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
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
FEDERATION AMER SOC EXP BIOL. 2008
View details for Web of Science ID 000208467807247
Promoting physical activity through hand-held computer technology
AMERICAN JOURNAL OF PREVENTIVE MEDICINE
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
Metabolic syndrome: do clinical criteria identify similar individuals among overweight premenopausal women?
METABOLISM-CLINICAL AND EXPERIMENTAL
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
Replacing sweetened caloric beverages with drinking water is associated with lower energy intake
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
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
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
A proposed method for assessing plasma hypertonicity in vivo
EUROPEAN JOURNAL OF CLINICAL NUTRITION
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
Composition, stability, and bioavailability of garlic products used in a clinical trial
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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
Soy, garlic, and ginkgo biloba: their potential role in cardiovascular disease prevention and treatment.
Current atherosclerosis reports
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
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 Web of Science ID 000182094900031
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
FEDERATION AMER SOC EXP BIOL. 2003: A372–A372
View details for Web of Science ID 000181733101768
Recent discoveries in inclusive food-based approaches and dietary patterns for reduction in risk for cardiovascular disease
CURRENT OPINION IN LIPIDOLOGY
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.
SPRINGER. 2002: 185–185
View details for Web of Science ID 000175158200735
Plant-based food intake and nutrient and phytochemical status in a national sample of ethnically diverse women (NHANES III)
FEDERATION AMER SOC EXP BIOL. 2002: A228–A228
View details for Web of Science ID 000174533601262
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
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 2001; 12 (7): 553-559
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
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
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
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
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
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
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
Clinical review 97 - Potential health benefits of dietary phytoestrogens: A review of the clinical, epidemiological, and mechanistic evidence
JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM
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
1998; 3 (1): 23-31
View details for Web of Science ID 000072410000002
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
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
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
MONOUNSATURATED VERSUS POLYUNSATURATED DIETARY-FAT AND SERUM-LIPIDS - A METAANALYSIS
ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY
1995; 15 (11): 1917-1927
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
DIETARY-INTAKE PATTERNS AND ACCULTURATION LEVELS OF HISPANIC IMMIGRANT MEN - A PILOT-STUDY
HISPANIC JOURNAL OF BEHAVIORAL SCIENCES
1995; 17 (3): 347-361
View details for Web of Science ID A1995RN39000005