MedWire News: A calorie-restricted vegetarian diet is more effective for reducing insulin resistance (IR) and body weight, and improving markers of oxidative stress in Type 2 diabetes than a low calorie non-vegetarian diet, show study results.
Terezie Pelikanova (Charles University, Prague, Czech Republic) and colleagues recruited 74 patients with Type 2 diabetes to take part in their study. Of these, 37 were assigned to follow a vegetarian diet (experimental group) and 37 to receive a conventional, non-vegetarian diet (control group). Both diets were calorie restricted (-500 kcal/day).
The researchers provided all meals for 24 weeks. To assess the additional effects of physical activity, all participants were assigned aerobic exercise - 60% maximum heart rate 2-3 times a week for 1 hour - as well as their allocated diet from week 12 to 24.
The prevalence of Type 2 diabetes in vegetarians is only half that of non-vegetarians. Changing to a vegetarian diet has been shown to improve weight and glycemic outcomes in patients with Type 2 diabetes in previous studies, but the mechanisms behind this are unclear.
Writing in the journal Diabetic Medicine, Pelikanova and team report that 43% of those in the experimental group compared with only 5% of controls reduced their diabetes medication by week 24.
Reduction in body weight was also significantly greater in the experimental than the control group over the study period, at 6.2 versus 3.2 kg, as was increase in insulin sensitivity, at 30% versus 20%.
Additionally, visceral and subcutaneous fat, leptin, and glutathione decreased and vitamin C, superoxide dismutase, and plasma adiponectin increased significantly more in the experimental than the control group.
The addition of aerobic exercise did not reduce the disparity between the two groups, but actually served to increase the between-group difference in glycemic and other outcomes between the experimental and control groups.
"A vegetarian diet alone or in combination with exercise is more effective in increasing insulin sensitivity, reducing volume of visceral fat and improving plasma concentrations of adipokines and oxidative stress markers than a conventional diabetic diet with or without the addition of exercise," concludes the team.
"Further studies should explore the precise mechanisms and long-term effects of vegetarian diets in patients with Type 2 diabetes."
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