Effect of ethanol on lipoprotein synthesis and fecal sterol excretion

The effect of variable doses of ethanol on plasma lipoprotein composition, lipoprotein synthesis and fecal sterol excretion was examined in male, atherosclerosis susceptible squirrel monkeys. Primates were divided into three groups: 1) Controls fed isocaloric liquid diet; 2) Low Ethanol monkeys given liquid diet with vodka substituted isocalorically for carbohydrate at 12% of calories; and 3) High Ethanol animals fed diet plus vodka at 24% of calories. Circulating high density lipoprotein (HDL) free cholesterol and phospholipid, very low density-low density lipoprotein (VLDL-LDL) total cholesterol, and total plasma cholesterol and triglyceride were significantly elevated in High Ethanol primates compared to the other treatments. However, the percent distribution of cholesterol among the lipoprotein fractions was identical for the three groups. There were no significant differences in serum glutamate oxalo-acetate transaminase. High Ethanol primates also had significantly greater HDL free cholesterol specific activity following intravenous injection of 3H mevalonolactone compared to the other groups while radioactive VLDL-LDL free cholesterol was elevated in both High and Low Ethanol animals. Although, total fecal bile acid mass was significantly greater in both alcohol treatment groups compared to Controls, fecal neutral sterol specific activity was only higher in monkeys fed the high ethanol diet. This study provides evidence that ethanol at 24% of calories: 1) raises HDL cholesterol levels by enhancing lipoprotein synthesis; 2) increases the fecal output of newly synthesized cholesterol without causing liver dysfunction; and 3) maintains a constant relative distribution of cholesterol among lipoprotein classes.