Impact of the Mediterranean diet and weight loss on surrogate markers of cholesterol homeostasis in men with the metabolic syndrome

This study examined for the first time the impact of the Mediterranean type diet (MedDiet) consumed under controlled feeding conditions, with and without weight loss, on surrogate markers of cholesterol (C) absorption, synthesis and clearance using plasma phytosterol, lathosterol and proprotein convertase subtilisin/kexin type 9 (PCSK9) concentrations respectively, in men with metabolic syndrome (MS).Nineteen men (24–62 years) with MS first consumed a control Western‐type diet for 5 weeks followed by a 5‐week MedDiet, both under weight‐maintaining isocaloric feeding conditions. They then underwent a 20‐week caloric restriction phase that led to a 10.2 ± 2.9% reduction in body weight (P <0.01), followed by the consumption of an isocaloric MedDiet for 5 weeks. The MedDiet without weight loss significantly reduced plasma LDL‐C (−9.9%), PCSK9 (−11.7%) and the campesterol/C ratio (−38.3%, all P<0.01) compared with the control diet. MedDiet with weight loss had no additional impact on these markers of cholesterol homeostasis and on plasma LDL‐C concentrations but significantly reduced the lathosterol/C ratio by 17.5% (P=0.007) compared with the control diet. The reduction in plasma LDL‐C concentrations with the MedDiet without weight loss appears to be primarily attributable to an increase in LDL clearance and reduced cholesterol absorption.