Beneficial role of dietary folic acid on cholesterol and bile acid metabolism in ethanol-fed rats.

OBJECTIVE: Cholesterol metabolism is altered by chronic ethanol consumption. In previous articles, we demonstrated the anti-oxidant capacity of folic acid, which may be useful in the prevention of damage provoked by ethanol. We want to determine the effects of ethanol on cholesterol and bile metabolism and whether a folic acid-supplemented diet could change alterations provoked by a chronic ethanol intake in rats.

METHOD: We used four experimental groups: (1) control, (2) alcohol, (3) alcohol supplemented with folic acid, and (4) control supplemented with folic acid. In all the experimental groups, we measured hepatic 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, and cholesterol and bile acids in serum, liver, bile, and feces.

RESULTS: We have found that the alcohol-fed groups showed high hepatic HMG-CoA reductase activity, total hepatic and serum cholesterol concentration, bile cholesterol secretion concentration, and cholesterol enterohepatic circulation. Total serum and hepatic cholesterol levels decreased when alcohol-fed rats were supplemented with folic acid. The hepatic bile acid concentration increased in both chronic ethanol groups. Folic acid supplementation significantly increased bile cholesterol secretion, the bile acids in bile, and fecal bile acid excretion in ethanol-exposed rats. The independent bile acid fraction showed no significant differences between both ethanol groups with respect to Na+, K+, and Cl- concentrations.

CONCLUSIONS: Folic acid increases bile flow, bile acid synthesis from cholesterol, and bile acid excretion via feces, thus provoking a decrease in serum and hepatic cholesterol. However none of these actions were observed in supplemented control rats. This, therefore, could be yet another beneficial effect of folic acid on alcoholic patients.