Mediterranean Diet and Metabolic Syndrome

Abstract

Mediterranean diet and the metabolic syndrome Background: The metabolic syndrome refers to a clustering of risk factors including abdominal obesity, hyperglycaemia, low HDL-cholesterol, hypertriglyceridaemia, and hypertension and it is a risk factor for diabetes mellitus type 2 and cardiovascular disease. In this thesis we studied whether a Mediterranean diet favourably affects the metabolic syndrome. Methods: We assessed the association between a Mediterranean diet and the metabolic syndrome in apparently healthy elderly European subjects (SENECA study) and in a Dutch study population that was oversampled with subjects with impaired glucose tolerance or diabetes mellitus type 2 (CoDAM study). In addition, we conducted a controlled-feeding trial to compare the effects of replacing a high saturated fatty acids (SFA) diet with a high monounsaturated fatty acids (MUFA) diet or a Mediterranean diet on characteristics of the metabolic syndrome: HDL-cholesterol, triglycerides and glucose metabolism (glucose concentration and insulin sensitivity). Results: In both the SENECA study and the feeding trial we find support for the hypothesis that a Mediterranean diet has a beneficial effect on two characteristics of the metabolic syndrome, namely HDL-cholesterol and triglyceride concentrations. In addition, the findings of the SENECA study suggested that subjects with good adherence to a Mediterranean diet had a lower prevalence of the metabolic syndrome (prevalence ratio 0.81, 95%CI 0.65; 1.03) and a smaller waist circumference (-1.1 cm, 95%CI -2.4; 0.3) than subjects with poor adherence. In the CoDAM study, we did not find these associations. In none of our studies we found support for the hypothesis that a Mediterranean diet has a beneficial effect on glucose concentration, insulin sensitivity or blood pressure. Conclusion: This thesis finds support for a beneficial effect on two out of five characteristics of the metabolic syndrome and also suggests a beneficial effect on a third characteristic (abdominal obesity). We therefore conclude that a Mediterranean diet may help to prevent the metabolic syndrome and consequently diabetes mellitus type 2 and cardiovascular disease.