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.
Observational study of lipid profile and LDL particle size in patients with metabolic syndrome