Are Vegetarian and Vegan Diets Best for Preventing and Treating Diabetes?
Are Vegetarian and Vegan Diets Best for
Preventing and Treating Diabetes?
Editor's Note: The following is an edited, translated transcript of a video commentary by endocrinologist-nutritionist Boris Hansel, MD, an obesity management specialist who practices in Paris, France.I'm going to try to answer a question asked by both patients and care providers: Is a vegetarian or vegan diet the ideal diet for preventing and treating diabetes? A quick Internet search would yield plenty of popular articles that advocate a vegetarian diet. According to certain websites, such a diet prevents the onset of diabetes or, in the case of confirmed diabetes, enables one to stop treatments.Of course, such claims are completely false. What's more challenging, however, is to determine whether a vegetarian diet is the one that should be recommended on a first-line basis in patients with diabetes in the hopes of achieving diabetic control and preventing complications.As for randomized trials, it must be said that they are of short duration. For the most part, when we look at the meta-analyses, we find greater weight loss with vegetarian diets than with the diets tested in the control groups.The main hypothesis for explaining this difference in weight loss between the groups is that in the open-label studies, the participants in the intervention group were more or less consciously influenced to lose weight, even if, in principle, weight loss was not an objective. Therefore, weight loss would have been what was responsible for the improvement in glycemic control rather than the quality of the diet, per se.Also, it is well known that high-protein or high-fat diets have a dramatic effect on glycemic control in patients with diabetes, in addition to bringing about rapid weight loss.Ideally, these diets should be compared if one really wants to conclude that vegetarianism is superior. It is a shortcoming all the more so because there is abundant literature in favor of the Mediterranean diet for preventing and treating cardiometabolic risk factors, and especially for improving glycemic control in diabetics.Although no clinical trial has compared the vegetarian diet with the Mediterranean diet, there is a recently published network meta-analysis[2] from which one can make an indirect comparison between the vegetarian and Mediterranean diets and, more generally, other types of diets—namely, the Paleo diet, high-protein diet, low-carb diet, and a diet with low glycemic index and load.The overall finding of this network meta-analysis is in favor of the Mediterranean diet when it comes to glycemic control. The Mediterranean diet seems to be at least as effective or even superior to a vegetarian diet, which does not fare so badly either and which is associated with better diabetes control.