Effects of Diet and Exercise on Qualitative and Quantitative Measures of LDL and Its Susceptibility to Oxidation

Abstract

The purpose of this study was to investigate the effects of an intensive diet and exercise program on the quantity and quality of LDL as well as its susceptibility to in vitro oxidation. The diet was low in fat (P <.01) in serum levels of cholesterol (20%), LDL-cholesterol (20%), HDL-cholesterol (17%), triglycerides (26%), and glucose (16%) as well as in body weight (4%) were noted for the total population. The mean particle diameter of the LDL increased (24.2±0.2 to 25.1±0.14 nm, P <.01) and was correlated with the reduction in serum triglycerides ( r =.58, P <.01). Six of 22 subjects changed in LDL phenotype from B (≤25.5 nm) to A (>25.5 nm). The percentage of LDL-cholesterol carried in the more dense subfractions fell significantly, while that carried by the less dense fractions increased. Initial oxidation levels fell (21%), while the lag time before copper-induced oxidation increased (13%). Reductions were observed in both the rate of oxidation (16%) and peak oxidation (20%). All of these changes should result in a dramatic reduction in the risk for atherosclerosis and its clinical sequelae.