Mediterranean diet and insulin sensitivity, lipid profile and blood pressure levels, in overweight and obese people; The Attica study

BACKGROUND: We aimed to investigate if overweight and obese adults "close" to Mediterranean diet present better insulin, lipids profile and better pressure levels, compared to individuals close to a more Westernized diet. METHODS: The ATTICA study is a population-based cohort that has randomly enrolled 3042 adult men and women, stratified by age – gender, from the greater area of Athens, during 2001–2002. Of them, in this work were have studied 1762 participants with excess body weight, meaning overweight (BMI: 25–29.9 kg/m(2)) and obese (BMI>30 kg/m(2)). 1064 were men and 698 women (20–89 years old). Adherence to Mediterranean diet was assessed through a diet-score that was based on a validated food-frequency questionnaire. Blood pressure was measured and also fasting glucose, insulin and blood lipids. Insulin sensitivity was also assessed by the homeostasis model assessment (HOMA) approach (glucose × insulin/22.5). RESULTS: Individuals with excess bodyweight in the highest tertile of diet score, were more insulin sensitive than those in the lowest tertile (11.4% lower HOMA, p = 0.06), had 13% lower levels of total cholesterol (p = 0.001) and 3 mmHg decrease of systolic blood pressure levels (p < 0.001), when adjusted for age, sex and BMI. Multivariate analysis after taking into account several confounders demonstrated that insulin sensitivity, total cholesterol and systolic blood pressure were independently but only modestly correlated with Mediterranean diet in people with excess bodyweight. CONCLUSION: Adherence to Mediterranean diet is modeslty associated with a better insulin sensitivity, lower levels of total cholesterol and lower levels of systolic blood pressure in overweight and obese subjects. This may suggest that compared to general population, the beneficial effect of this diet in cardiovascular system of excess body weight people is limited.