Usefulness of Vegetarian and Vegan Diets for Treating Type 2 Diabetes
Significant benefits for diabetes prevention and management have been observed with vegetarian and especially vegan diets. This article reviews observational studies and intervention trials on such diets, and discusses their efficacy, nutritional adequacy, acceptability, and sustainability. Research to date has demonstrated that a low-fat, plant-based nutritional approach improves control of weight, glycemia, and cardiovascular risk. These studies have also shown that carefully planned vegan diets can be more nutritious than diets based on more conventional diet guidelines, with an acceptability that is comparable with that of other therapeutic regimens. Current intervention guidelines from professional organizations offer support for this approach. Vegetarian and vegan diets present potential advantages in managing type 2 diabetes that merit the attention of individuals with diabetes and their caregivers.
KeywordsVegetarian diet Vegan diet Type 2 diabetes
The authors wish to acknowledge Heather J. Katcher, PhD, RD, for her helpful review and editing of the manuscript.
No potential conflicts of interest relevant to this article were reported.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
- 1.World Health Organization: Country and regional data—World: Prevalence of diabetes worldwide. Available at http://www.who.int/diabetes/facts/world_figures/en/index.html. Accessed December 2009.
- 5.• 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. This study of individuals with type 2 diabetes demonstrated that long-term weight reduction may be facilitated with a low-fat vegan diet or a diet based on conventional guidelines. The vegan diet appeared to be more effective for control of glycemia and plasma lipid concentrations when medication changes were controlled. The vegan diet achieved beneficial outcomes without requiring restrictions of total caloric intake, carbohydrates, or portion sizes.Google Scholar
- 18.•• Tonstad S, Butler T, Yan R, Fraser GE: Type of vegetarian diet, body weight, and prevalence of type 2 diabetes. Diabetes Care 2009, 32:791–796. This cohort study of 60,903 individuals found that those following a vegan diet had approximately half the risk of type 2 diabetes, compared with those following nonvegetarian diets, in analyses controlled for body weight, activity, and socioeconomic and lifestyle factors. Inclusion of meat or dairy products, even on a less-than-weekly basis, was associated with increased risk.Google Scholar
- 23.CDC: National Diabetes Fact Sheet, 2007. Available at http://www.cdc.gov/diabetes/pubs/pdf/ndfs_2007.pdf. Accessed December 2009.
- 34.McDougall J: Sex and still aging. McDougall Newsletter 2007, 6:1. Available at http://www.drmcdougall.com/misc/2007nl/aug/fav5.htm. Accessed December 2009.
- 35.Barnard ND, ed.: Dr. Neal Barnard's Program for Reversing Diabetes. New York: Rodale, Inc.; 2007.Google Scholar
- 36.• Turner-McGrievy GM, Barnard ND, Cohen J, et al.: 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. This randomized, controlled clinical study found that participants following a low-fat, plant-based diet almost doubled their intake of fruit and vegetables, and improved the overall nutritional quality of their diet to a greater extent than those following a conventional diabetes diet. Both dietary groups were low in vitamins D and E, calcium and potassium, and consumed excess sodium.Google Scholar
- 38.•• Craig WJ, Mangels AR: Position of the American Dietetic Association: vegetarian diets. J Am Diet Assoc 2009, 109:1266–1282. This position paper offers a comprehensive, evidence-based summary of the health effects of vegetarian and vegan diets across the life span and their role in the preventing and treating specific chronic diseases. Important nutrition considerations are addressed.Google Scholar
- 52.Food and Agriculture Organization of the United Nations: Livestock's Long Shadow: Environmental Issues and Options. Available at http://www.fao.org/docrep/010/a0701e/a0701e00.HTM. Accessed December 2009.