A Low Glycemic Index Mediterranean Diet in the Treatment of Metabolic Syndrome. A Randomized Controlled Trial.

Metabolic Syndrome (MetS) is a cluster of multiple risk factors of metabolic origin, associated with an increased risk of cardiovascular disease, type 2 diabetes mellitus and other diseases, including some cancers. The National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) defines MetS the presence of at least three of five diagnostic criteria consisting in the measure of waist circumference, fasting glucose, systolic pressure and/or diastolic blood pressure, serum triglycerides and HDL cholesterol. The level of physical activity, smoking habits, low social class membership as well as low level of education and even a mild degree of chronic inflammation have been associated with an increased risk of MetS. Recently, there has been an increased interest of researchers in the relationship between MetS and diet, and more specifically Mediterranean Diet (MD). A problem of the contemporary MD is the quality of carbohydrates as the foods rich in carbohydrates consumed actually, such as white bread and some type of pasta, are produced with refined flour, at high glycemic index (GI) and load (GL). There are numerous studies showing that taking large amounts of high GI and GL foods is a risk factor for coronary heart disease and type 2 diabetes. To our knowledge there is no diet trial that compared the health effects of Mediterranean diets with different quality of carbohydrates. Objective of this study was to compare, in a randomized clinical trial, the effects of a simple MD, a Low Glycemic Index diet (LGID), and a Low Glycemic Index MD (LGIMD) on MetS, MetS components and other metabolic variables. For this reason, after a baseline examination, participants were randomly divided into three groups, each receiving a specific dietary intervention, and all the parameters measured at the first visit were examined again at months third and sixth.