The effect of a high-carbohydrate diet on apo E-poor and apo E-rich HDL subparticles in NIDDM

Background and Aim: HDL cholesterol levels are decreased by a high-carbohydrate diet in subjects with NIDDM. However, as HDL particles are heterogenous in nature, the aim of this study was to examine the effect of a high-carbohydrate diet on apo E-poor and apo E-rich HDL particles in NIDDM. Methods and Results: A crossover study of 4 weeks duration, comparing a high fat (40% fat, 40% carbohydrate and 20% protein) and a high-carbohydrate diet (60% carbohydrate, 20% fat and 20% protein) was performed in 7 subjects with non insulin-dependent diabetes mellitus. HDL fraction was isolated by fast phase liquid chromatography and HDL subfractions separated by heparin affinity chromatography. Lipid and apolipoproteins were measured in these fractions in the fasting and postprandial states on both diets. The apolipoprotein composition of apo E-poor and apo E-rich HDL is different but is not affected by diet. In the postprandial phase, apo E-rich HDL apoproteins AI, AII, CI, CIII, and E decrease while the apo E-poor HDL apo CII decreases. Although fasting apo E-rich HDL cholesterol was similar on both diets, using repeated measures analysis of variance, apo E-rich HDL cholesterol was lower on the high-carbohydrate diet. Conclusions: This study suggests that the apolipoprotein composition of apo E-poor and apo E-rich HDL are different, that these particles may have distinct roles in postprandial metabolism, and that a high-carbohydrate diet in NIDDM decreases cholesterol concentration of the apo E-rich HDL fraction.