The effect of short-term fasting, apolipoprotein E gene polymorphism, and sex on plasma lipids

The effect of 1 wk of supervised fasting on plasma lipid concentrations in subjects with different apolipoprotein E (apo E) phenotypes was studied in 58 healthy free-living volunteers. The participants consumed an 870-kJ(208 kcal)/d liquid diet containing fruit and berry juices, tea, and water. The decline in plasma total cholesterol during 1 wk of fasting was 0.46 mmol/L in women and 0.35 mmol/L in men. The decreases were significant in both women and men. The response patterns of plasma total cholesterol were not significantly different between the sexes. In men, the changes in plasma low-density-lipoprotein cholesterol during the fast differed significantly (P = 0.0181) between the apo E phenotypes, whereas in women there were no differences due to phenotype (P = 0.695). The magnitude of the change in plasma triacylglycerol during the fast was different between the sexes (P = 0.0099). The changes in plasma triacylglycerols differed significantly between apo E phenotype groups in men (P = 0.0295) but not in women (P = 0.0661). Statistical comparison between different apo E phenotypes was performed with and without the small apo E3,2+E2,2 group, with essentially similar results. During fasting, plasma high-density-lipoprotein cholesterol concentrations decreased slightly but not significantly. The study shows significant differences in the associations of apo E alleles and sex on plasma lipid responses during fasting and illustrates the importance of gene-diet interactions in the regulation of lipid metabolism in humans.