Abstract 127: The Mediterranean Diet With and Without Weight Loss Improves Several Features of Low-Density Lipoprotein Metabolism in Men With Metabolic Syndrome

Abstract

Objective To assess the impact of a Mediterranean type diet (MedDiet), without weight loss (-WL) and with weight loss (+WL), on features of LDL and LDL- apolipoprotein (apo) B metabolism in men with metabolic syndrome (MetS). Methods and Results The diet of 19 men with MetS (NCEP-ATP III, age 24-62 years) was first standardized to a typical North American control diet that they consumed for 5 weeks under isoenergetic feeding conditions (all foods and beverages provided). Subjects were then fed a MedDiet for 5 weeks also under isoenergetic conditions (MedDiet-WL), after which they underwent a 20-week weight loss period in free-living conditions (average weight loss -10.2 ± 2.9% body weight, P<0.01). This was followed by consumption of the MedDiet (5 weeks) under isoenergetic conditions (MedDiet+WL). Features of LDL and apo B kinetics were assessed at the end of the three controlled feeding periods. MedDiet-WL reduced VLDL-apoCIII (-41.5%), cholesteryl ester transfer protein (-7.0%) and hepatic lipase concentrations (-7.1%), reduced the proportion of small LDL (LDL<255 å, -11.7%) and increased LDL peak particle diameter (LDL-PPD, +0.7%) as well as the proportion of medium size LDL (LDL255-260 å, +11.1%) vs. control diet (all P<0.05). MedDiet-WL also decreased LDL-apoB pool size (PS, -14.2%) and increased the fractional catabolic rate (FCR) of LDL-apoB (+30.4%) vs. the control diet (both P<0.05), with no change in LDL-apoB production rate (PR). MedDiet+WL was associated with further increase in LDL-PPD (0.2%) and further reduction in VLDL-apoCIII concentrations (-28.7%) compared with MedDiet-WL (both P<0.05) but had no further impact on LDL-apoB PS and on LDL-apoB FCR. Conclusion Data from this controlled feeding study suggest that consumption of MedDiet, even in the absence of weight loss, decreases LDL-C concentrations and LDL-apoB pool size primarily by enhancing the clearance of LDL particles in men with MetS. This is accompanied by a reduction in the proportion of small dense LDL and an increase in LDL particle size. Combining weight loss to MedDiet has no additional impact on LDL-apoB pool size and catabolism but may have further beneficial effects on the LDL particle size phenotype in men with MetS.