Mediterranean diet and the metabolic syndrome

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.