Clinical Research

The Physicians Committee designs and conducts clinical research studies on nutrition and health. Dietary interventions have appeared promising in investigations carried out by numerous research teams, including our own. We have conducted studies that examine the effects of diet on weight, cardiovascular risk, cancer prevention and survival, and other health issues. The Physicians Committee's research aims to develop and test practical interventions that can be used by doctors and patients. The Physicians Committee also conducts detailed reviews of the scientific literature, including meta-analyses.

List: Bunner AE, Wells CL, Gonzales J, Agarwal U, Bayat E, Barnard ND. A dietary intervention for chronic diabetic neuropathy pain: a randomized controlled pilot study. Nutrition & Diabetes. 2015;5:e158.

• Barnard ND, Cohen J, Jenkins DJ, et al. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care. 2006;29:1777-1783. 
• Turner-McGrievy GM, Barnard ND, Cohen J, Jenkins DJ, Gloede L, Green AA. Changes in nutrient intake and dietary quality among participants with type 2 diabetes following a low-fat vegan diet or a conventional diabetes diet for 22 weeks. J Am Diet Assoc. 2008;108:1636-1645. 
• Barnard ND, Cohen J, Jenkins DJ, et al. A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial. Am J Clin Nutr. 2009;89:1588S-1596S. 
• Barnard ND, Noble EP, Ritchie T, et al. D2 dopamine receptor Taq1A polymorphism, body weight, and dietary intake in type 2 diabetes. Nutrition. 2009;25:58-65. 
• Barnard ND, Gloede L, Cohen J, et al. A low-fat vegan diet elicits greater macronutrient changes, but is comparable in adherence and acceptability, compared with a more conventional diabetes diet among individuals with type 2 diabetes. J Am Diet Assoc. 2009;109:263-272. 
• Kahleova H, Tura A, Hill M, Holubkov R, Barnard ND. A plant-based dietary intervention improves beta-cell function and insulin resistance in overweight adults. A 16-week randomized clinical trial. Nutrients. 2018;10:pii: E189.

• Ferdowsian HR, Barnard ND, Hoover VJ, et al. A multicomponent intervention reduces body weight and cardiovascular risk at a GEICO corporate site. Am J Health Promot. 2010;24:384-387.
• Levin SM, Ferdowsian HR, Hoover VJ, Green AA, Barnard ND. A worksite programme significantly alters nutrient intakes. Public Health Nutr. 2010;13:1629-1635.
• Katcher HI, Ferdowsian HR, Hoover VJ, Cohen JL, Barnard ND. A worksite vegan nutrition program is well-accepted and improves health-related quality of life and work productivity. Ann Nutr Metab. 2010;56:245-252.
• Turner-McGrievy GM, Jenkins DJ, Barnard ND, Cohen J, Gloede L, Green AA. Decreases in dietary glycemic index are related to weight loss among individuals following therapeutic diets for type 2 diabetes. J Nutr. 2011;141:1469-1474.

• Agarwal U, Mishra S, Xu J, Levin S, Gonzales J, Barnard ND. A Multicenter Randomized Controlled Trial of a Nutrition Intervention Program in a Multiethnic Adult Population in the Corporate Setting Reduces Depression and Anxiety and Improves Quality of Life: The GEICO Study. Am J Health Promot. 2015;29:245-54.
• Mishra S, Xu J, Agarwal U, Gonzales J, Levin S, Barnard ND. A multicenter randomized controlled trial of a plant-based nutrition program to reduce body weight and cardiovascular risk in the corporate setting: the GEICO study. Eur J Clin Nutr. 2013;67:718-724.
• Mishra S, Barnard ND, Gonzales J, Xu J, Agarwal U, Levin S. Nutrient intake in the GEICO multicenter trial: the effects of a multicomponent worksite intervention. Eur J Clin Nutr. 2013;67:1066-1071.

Barnard ND, Alwarith J, Rembert E, et al. A Mediterranean diet and low-fat vegan diet to improve body weight and cardiometabolic risk factors: a randomized, cross-over trial. J Am Nutr Assoc. 2022;41(2):127-139. doi:10.1080/07315724.2020.1869625

• Kahleova H, Znayenko-Miller T, Uribarri J, et al. Dietary advanced glycation end-products and postmenopausal hot flashes: a post-hoc analysis of a 12-week randomized clinical trial. Maturitas. 2023;172:32-38. doi:10.1016/j.maturitas.2023.03.008
• Barnard ND, Kahleova H, Holtz DN, et al. A dietary intervention for vasomotor symptoms of menopause: a randomized, controlled trial. Menopause. 2023;30(1):80-87. doi:10.1097/GME.0000000000002080
• Barnard ND, Kahleova H, Holtz DN, et al. The Women's Study for the Alleviation of Vasomotor Symptoms (WAVS): a randomized, controlled trial of a plant-based diet and whole soybeans for postmenopausal women. Menopause. 2021;28(10):1150-1156.

Barnard ND, Levin S, Crosby L, Flores R, Holubkov R, Kahleova H. A randomized, crossover trial of a nutritional intervention for rheumatoid arthritis. Am J Lifestyle Med. Published online April 3, 2022. doi:10.1177/15598276221081819

Reynolds A, The Diabetes and Nutrition Study Group (DNSG) of the European Association for the Study of Diabetes (EASD). Evidence-based European recommendations for the dietary management of diabetes. Diabetologia. Published online April 17, 2023. doi:10.1007/s00125-023-05894-8

Cullimore JP, Herby AR, Paul-Quinn JL, Levin S, Stancic S. The nutritional content of animal and plant milks and their health implications. International Journal of Disease Reversal and Prevention. 2023;5(1):13. doi:10.22230/ijdrp.2023v5n1a363

Herby A, Cullimore J, Paul-Quinn J, Crosby L. Dairy intake and incidence of common cancers in prospective studies: a narrative review. International Journal of Disease Reversal and Prevention. 2023;5(1):14. doi:10.22230/ijdrp.2023v5n1a365

Barnard ND, Holtz DN, Schmidt N, et al. Nutrition in the prevention and treatment of endometriosis: a review. Front Nutr. 2023;10:1089891. doi:10.3389/fnut.2023.1089891

Kahleova H, Znayenko-Miller T, Uribarri J, Holubkov R, Barnard ND. Dietary advanced glycation products and their associations with insulin sensitivity and body weight: a 16-week randomized clinical trial. Obesity Science and Practice. Published online October 17, 2022. doi:10.1002/osp4.646

Crosby L, Rembert E, Levin S, et al. Changes in food and nutrient intake and diet quality on a low-fat vegan diet are associated with changes in body weight, body composition, and insulin sensitivity in overweight adults: a randomized clinical trial. J Acad Nutr Diet. 2022;122(10):1922-1939.e0. doi:10.1016/j.jand.2022.04.008

Stancic S, Cullimore J, Barnard N. Six applications of plant based diets for health promotion. Am J Lifestyle Med. 2022;16(4):434-438. doi:10.1177/15598276221104023

Kahleova H, Barnard ND. The role of nutrition in COVID-19: taking a lesson from the 1918 H1N1 pandemic. Am J Lifestyle Med. 2022;17(1):161-163. doi:10.1177/15598276221097621

Kahleova H, Barnard ND. Can a plant-based diet help mitigate Covid-19? Eur J Clin Nutr. 2022;76(7):911-912. doi:10.1038/s41430-022-01082-w

Kahleova H, Berrien-Lopez R, Holtz D, et al. Nutrition for hospital workers during a crisis: effect of a plant-based dietary intervention on cardiometabolic outcomes and quality of life in healthcare employees during the COVID-19 pandemic. Am J Lifestyle Med. 2021;16(3):399-407. doi:10.1177/15598276211050339

Stancic S, Cullimore J, Barnard ND. Shoring up vaccine efficacy. Am J Med. 2022;135(3):271-272. doi:10.1016/j.amjmed.2021.09.002

Crosby L, Davis B, Joshi S, et al. Ketogenic diets and chronic disease: weighing the benefits against the risks. Front Nutr. 2021;8:702802. doi:10.3389/fnut.2021.702802

doi:10.1097/GME.0000000000001812

Jardine MA, Kahleova H, Levin SM, Ali Z, Trapp CB, Barnard ND. Perspective: plant-based eating pattern for type 2 diabetes prevention and treatment: efficacy, mechanisms, and practical considerations. Adv Nutr. 2021;12(6):2045-2055. doi:10.1093/advances/nmab063

Barnard ND, Rembert E, Freeman A, Bradshaw M, Holubkov R, Kahleova H. Blood type is not associated with changes in cardiometabolic outcomes in response to a plant-based dietary intervention. J Acad Nutr Diet. 2021;121(6):1080-1086. doi:10.1016/j.jand.2020.08.079

Kahleova H, Levin S, Barnard ND. Plant-based diets for healthy aging. J Am Coll Nutr. 2021;40(5):478-479. doi:10.1080/07315724.2020.1790442

Kahleova H, Petersen KF, Shulman GI, et al. Effect of a low-fat vegan diet on body weight, insulin sensitivity, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults: a randomized clinical trial. JAMA Netw Open. 2020;3(11):e2025454. doi:10.1001/jamanetworkopen.2020.25454

Kahleova H, Carlsen B, Berrien Lopez R, Barnard ND. Anti-diabetic, haematinic and anti-cholesterolmic effects of wheat (Triticum aestivum Linn.) Plant-based diets for type 1 diabetes. J Diab Metab. 2020;11:847. doi:10.35248/2155-6156.20.11.847

Barnard ND, Long MB, Ferguson JM, Flores R, Kahleova H. Industry funding and cholesterol research: a systematic review. Am J Lifestyle Med. 2019;15(2):165-172. doi:10.1177/1559827619892198

Viguiliouk E, Glenn AJ, Nishi SK, et al. Associations between dietary pulses alone or with other legumes and cardiometabolic disease outcomes: an umbrella review and updated systematic review and meta-analysis of prospective cohort studies. Adv Nutr. 2019;10(Suppl_4):S308-S319. doi:10.1093/advances/nmz113

Flores R, Eckart J, Nash K, Kwitowski E. Implementation of vegan entrees in a Washington, D.C. elementary school. Journal of Child Nutrition and Management. 2019;43(2).

Alwarith J, Kahleova H, Rembert E, et al. Nutrition interventions in rheumatoid arthritis: the potential use of plant-based diets. A review. Front Nutr. 2019;6:141. doi:10.3389/fnut.2019.00141

Sandefur K, Kahleova H, Desmond AN, Elfrink E, Barnard ND. Crohn's disease remission with a plant-based diet: a case report. Nutrients. 2019;11(6):1385. doi:10.3390/nu11061385

Kahleova H, Tura A, Klementova M, et al. A plant-based meal stimulates incretin and insulin secretion more than an energy- and macronutrient-matched standard meal in type 2 diabetes: a randomized crossover study. Nutrients. 2019;11(3):486. doi:10.3390/nu11030486

Klementova M, Thieme L, Haluzik M, et al. A plant-based meal increases gastrointestinal hormones and satiety more than an energy- and macronutrient-matched processed-meat meal in T2D, obese, and healthy men: a three-group randomized crossover study. Nutrients. 2019;11(1):157. doi:10.3390/nu11010157

Viguiliouk E, Kendall CW, Kahleová H, et al. Effect of vegetarian dietary patterns on cardiometabolic risk factors in diabetes: a systematic review and meta-analysis of randomized controlled trials. Clin Nutr. 2019;38(3):1133-1145. doi:10.1016/j.clnu.2018.05.032

Chiavaroli L, Nishi SK, Khan TA, et al. Portfolio dietary pattern and cardiovascular disease: a systematic review and meta-analysis of controlled trials. Prog Cardiovasc Dis. 2018;61(1):43-53. doi:10.1016/j.pcad.2018.05.004

Kahleova H, Levin S, Barnard ND. Vegetarian dietary patterns and cardiovascular disease. Prog Cardiovasc Dis. 2018;61(1):54-61. doi:10.1016/j.pcad.2018.05.002

Barnard ND, Levin SM, Gloede L, Flores R. Turning the waiting room into a classroom: weekly classes using a vegan or a portion-controlled eating plan improve diabetes control in a randomized translational study. J Acad Nutr Diet. 2018;118(6):1072-1079. doi:10.1016/j.jand.2017.11.017

Kahleova H, Tura A, Hill M, Holubkov R, Barnard ND. A plant-based dietary intervention improves beta-cell function and insulin resistance in overweight adults: a 16-week randomized clinical trial. Nutrients. 2018;10(2):189. doi:10.3390/nu10020189

Kahleova H, Klementova M, Herynek V, et al. The effect of a vegetarian vs conventional hypocaloric diabetic diet on thigh adipose tissue distribution in subjects with type 2 diabetes: a randomized study. J Am Coll Nutr. 2018;36:364-369.

Barnard ND, Willett WC, Ding EL. The misuse of meta-analysis in nutrition research. JAMA. 2017;318:1435-1436.

Yokoyama Y, Levin SM, Barnard ND. Association between plant-based diets and plasma lipids: a systematic review and meta-analysis. Nutr Rev. 2017;75:683-698.

Kahleova H, Levin S, Barnard N. Cardio-metabolic benefits of plant-based diets. Nutrients. 2017; 9. pii: E848.

Kahleova H, Lloren JI, Mashchak A, Hill M, Fraser GE. Meal frequency and timing are associated with changes in body mass index in Adventist Health Study 2. J Nutr. 2017;147:1722-1728.

Freeman AM, Morris PB, Barnard N, et al. Trending cardiovascular nutrition controversies. J Am Coll Cardiol. 2017;69:1172-1187.

Barnard ND, Levin SM, Yokoyama Y. A systematic review and meta-analysis of changes in body weight in clinical trials of vegetarian diets. J Acad Nutr Diet. 2015;115:954-969.

Yokoyama Y, Barnard ND, Levin SM, Watanabe M. Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Cardiovasc Diagn Ther. 2014;4:373-82.

Bunner AE, Agarwal U, Gonzales JF, Valente F, Barnard ND. Nutrition intervention for migraine: a randomized crossover trial. J Headache Pain. 2014 Oct 23;15:69

Barnard ND, Bunner AE, Agarwal U. Saturated and trans fats and dementia: a systematic review. Neurobiol Aging. 2014;35(Suppl 2):S65-73.

Barnard ND, Bush AI, Ceccarelli A, et al. Dietary and lifestyle guidelines for the prevention of Alzheimer's disease. Neurobiol Aging. 2014;35(Suppl 2):S74-78.

Yokoyama Y, Nishimura K, Barnard ND, et al. Vegetarian diets and blood pressure: a meta-analysis. JAMA Intern Med. 2014;174:577-587.

Gonzales JF, Barnard ND, Jenkins DJ, Lanou AJ, Davis B, Saxe G, Levin S. Applying the precautionary principle to nutrition and cancer. J Am Coll Nutr. 2014;33:239-246.

Barnard ND. The physician's role in nutrition-related disorders: from bystander to leader. Virtual Mentor. 2013;15:367-372.

Agarwal U. Rethinking red meat as a prevention strategy for iron deficiency. Infant, Child, & Adolescent Nutrition. 2013;5:231-235.

Trapp CB, Barnard ND. Usefulness of vegetarian and vegan diets for treating type 2 diabetes. Curr Diab Rep. 2010;10:152-158.

Trapp C, Barnard N, Katcher H. A plant-based diet for type 2 diabetes: scientific support and practical strategies. Diabetes Educ. 2010;36:33-48.

Berkow SE, Barnard N, Eckart J, Katcher H. Four therapeutic diets: adherence and acceptability. Can J Diet Pract Res. 2010;71:199-204.

Barnard ND. Trends in food availability, 1909-2007. Am J Clin Nutr. 2010;91:1530S-1536S.

Lanou AJ. Should dairy be recommended as part of a healthy vegetarian diet? Am J Clin Nutr. 2009;89:1638S-1642S.

Barnard ND, Levin S. Vegetarian diets and disordered eating. J Am Diet Assoc. 2009;109:1523; author reply 1523-1524.

Spencer EH, Ferdowsian HR, Barnard ND. Diet and acne: a review of the evidence. Int J Dermatol. 2009;48:339-347.

Ferdowsian HR, Barnard ND. Effects of plant-based diets on plasma lipids. Am J Cardiol. 2009;104:947-956.

Barnard ND, Katcher HI, Jenkins DJ, Cohen J, Turner-McGrievy G. Vegetarian and vegan diets in type 2 diabetes management. Nutr Rev. 2009;67:255-263.

Lanou AJ, Barnard ND. Dairy and weight loss hypothesis: an evaluation of the clinical trials. Nutr Rev. 2008;66:272-279.

Turner-McGrievy GM, Barnard ND, Scialli AR. A two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat diet. Obesity (Silver Spring). 2007;15:2276-2281.

Barnard ND, Scialli AR, Turner-McGrievy G, Lanou AJ, Glass J. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am J Med. 2005;118:991-997. 

Turner-McGrievy GM, Barnard ND, Scialli AR, Lanou AJ. Effects of a low-fat vegan diet and a Step II diet on macro- and micronutrient intakes in overweight postmenopausal women. Nutrition. 2004;20:738-746. 

Barnard ND, Scialli AR, Hurlock D, Bertron P. Diet and sex-hormone binding globulin, dysmenorrhea, and premenstrual symptoms. Obstet Gynecol. 2000;95:245-250.

Barnard ND, Scialli AR, Bertron P, Hurlock D, Edmonds K, Talev L. Effectiveness of a low-fat vegetarian diet in altering serum lipids in healthy premenopausal women. Am J Cardiol. 2000;85:969-972.