Mediterranean diet and type 2 diabetes

Consumption of selected dietary components is favourably associated with prevention of type 2 diabetes, but discordant results for some foods or single nutrients continue to appear. The study of complete dietary patterns represents the most adequate approach to assess the role of diet on the risk of diabetes. The term 'Mediterranean diet' essentially refers to a primarily plant-based dietary pattern whose greater consumption has been associated with higher survival for lower all-cause mortality. At least five large prospective studies report a substantially lower risk of type 2 diabetes in healthy people or at risk patients with the highest adherence to a Mediterranean diet. Five randomized controlled trials have evaluated the effects of a Mediterranean diet, as compared with other commonly used diets, on glycaemic control in subjects with type 2 diabetes. Improvement of HbA1c levels was greater with a Mediterranean diet and ranged from 0.1% to 0.6% for HbA1c. No trial reported worsening of glycaemic control with a Mediterranean diet. Although no controlled trial specifically assessed the role of a Mediterranean diet in reducing cardiovascular events in type 2 diabetes, there is evidence that post-infarct or high-risk patients, including diabetic patients, may have cardiovascular benefits from a Mediterranean diet. The evidence so far accumulated suggests that adopting a Mediterranean diet may help prevent type 2 diabetes; moreover, a lower carbohydrate, Mediterranean-style diet seems good for HbA1c reduction in persons with established diabetes. © 2013 John Wiley & Sons, Ltd.