Effects of the traditional Mediterranean diet on adiponectin and leptin concentrations in men and premenopausal women: do sex differences exist?

BACKGROUND/OBJECTIVES: Most of the interventional studies have investigated the impact of the diet on adiponectin and leptin concentrations only in men or in women. Consequently, it is still unknown whether the consumption of a healthy diet influences in a sex-specific manner these adipocytokines. We examined sex differences in the effects of the Mediterranean diet (MedDiet) on adiponectin and leptin concentrations, and determined whether changes in these adipocytokines are associated with changes in cardiovascular risk factors in both sexes. SUBJECTS/METHODS: Participants were 38 men and 32 premenopausal women (24-53 years) with slightly elevated low-density lipoprotein cholestrol concentrations (3.4-4.9 mmol/l) or total cholesterol/high-density lipoprotein cholestrol (HDL-C) >= 5.0. Adiponectin, leptin and cardiovascular risk factors were measured before and after a 4-week fully controlled isoenergetic MedDiet. RESULTS: Adiponectin concentration decreased in response to the MedDiet, but this decrease reached statistical significance only in men (P < 0.001 for men and P=0.260 for women; sex-by-time interaction, P=0.072). Adjustments for body weight or waist circumference did not change results obtained. Changes in adiponectin were positively associated with concomitant variations in HDL-C in men (r= 0.52, P=0.003) and with variations in apolipoprotein A-1 and insulin sensitivity as calculated by both the homeostasis model assessment index for insulin sensitivity and Cederholm indices in women (respectively, r=0.44, P=0.021; r=0.79, P < 0.001 and r=0.47, P=0.020). The MedDiet had no impact on leptin and the leptin-to-adiponectin ratio in both sexes. CONCLUSIONS: Results suggest a sex difference in adiponectin response to the short-term consumption of the MedDiet, with only men experiencing a decrease. Also sex-specific patterns of associations between changes in adiponectin concentration and changes in cardiovascular risk factors were observed.