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

BackgroundAlthough vegan diets improve diabetes management, little is known about the nutrient profiles or diet quality of individuals with type 2 diabetes who adopt a vegan diet.ObjectiveTo assess the changes in nutrient intake and dietary quality among participants following a low-fat vegan diet or the 2003 American Diabetes Association dietary recommendations.DesignA 22-week randomized, controlled clinical trial examining changes in nutrient intake and diet quality.Subjects/settingParticipants with type 2 diabetes (n=99) in a free-living setting.Research design and methodsParticipants were randomly assigned to a low-fat vegan diet or a 2003 American Diabetes Association recommended diet.Main outcome measuresNutrient intake and Alternate Healthy Eating Index (AHEI) scores were collected at baseline and 22 weeks.Statistical analyses performedBetween-group t tests were calculated for changes between groups and paired comparison t tests were calculated for changes within-group. Pearson's correlation assessed relationship of AHEI score to hemoglobin A1c and body weight changes.ResultsBoth groups reported significant decreases in energy, protein, fat, cholesterol, vitamin D, selenium, and sodium intakes. The vegan group also significantly reduced reported intakes of vitamin B-12 and calcium, and significantly increased carbohydrate, fiber, total vitamin A activity, beta carotene, vitamins K and C, folate, magnesium, and potassium. The American Diabetes Association recommended diet group also reported significant decreases in carbohydrate and iron, but reported no significant increases. The vegan group significantly improved its AHEI score (P<0.0001), while the American Diabetes Association recommended diet group did not (P=0.7218). The difference in AHEI score at 22 weeks between groups was significant (P<0.0001). With both groups combined, AHEI score was negatively correlated with both changes in hemoglobin A1c value (r=–0.24, P=0.016) and weight (r=–0.27, P=0.007).ConclusionsVegan diets increase intakes of carbohydrate, fiber, and several micronutrients, in contrast with the American Diabetes Association recommended diet. The vegan group improved its AHEI score whereas the American Diabetes Association recommended diet group's AHEI score remained unchanged.