Athens, Greece – A diet high in monounsaturated fatty acids, fruits, vegetables, whole-grain cereals, and low-fat dairy products, coupled with fish, poultry, nuts, legumes, and a low consumption of red meat—also known as the Mediterranean diet—is associated with a lower prevalence and slower progression of metabolic syndrome, according to the results of a new meta-analysis [1].

In addition, adhering to the Mediterranean diet had favorable effects on individual components of the metabolic syndrome, including waist circumference, HDL-cholesterol and triglyceride levels, blood pressure, and glucose metabolism, report investigators.

“These results are of considerable public-health importance, because this dietary pattern can be easily adopted by all population groups and various cultures and cost-effectively serve for the primary and secondary prevention of the metabolic syndrome and its individual components,” write Christina-Maria Kastorini (Harokopio University, Athens, Greece) and colleagues in the March 15, 2011 issue of the Journal of the American College of Cardiology.

The results are from a meta-analysis of 35 clinical trials, two prospective studies, and 13 cross-sectional studies and include data on more than 500 000 study participants. Among the clinical trials and prospective studies, adherence to the Mediterranean diet was “highly protective,” report investigators, with those subjects adhering to the diet having a 31% lower risk of developing metabolic syndrome.

Two of four cross-sectional studies that looked at the relation between metabolic syndrome and the Mediterranean diet found that adherence to the diet was associated with beneficial effects on metabolic syndrome, but when all studies were combined, the protective effect of the diet did not reach statistical significance.

Data from the clinical trials also showed positive effects of the diet on the individual components of the metabolic syndrome. Overall, adherence to the diet in the 35 clinical trials was associated with a 42-cm reduction in waist circumference, a 1.17-mg/dL increase in HDL cholesterol, a 6.14-mg/dL decrease in triglyceride levels, a 2.35-mm-Hg and 1.58-mm-Hg reduction in systolic and diastolic blood pressure, respectively, and a 3.89-mg/dL reduction in glucose levels.

“The results of the present meta-analysis add to the existing knowledge, because they indicate that adherence to the Mediterranean diet has a positive effect on human health through different ways,” conclude Kastorini and colleagues. “The Mediterranean diet has a beneficial effect on abdominal obesity, lipid levels, glucose metabolism, and blood-pressure levels, all the components of the metabolic syndrome, which are also risk factors for the development of cardiovascular disease, insulin resistance, and diabetes.”