Hepatic vitamin A depletion after chronic ethanol consumption in baboons and rats

To evaluate possible effects of alcohol consumption on vitamin A and retinol-binding protein (RBP) status, baboons were pair-fed a nutritionally adequate liquid diet containing 50% of total calories either as ethanol or isocaloric carbohydrate. Fatty liver developed after 4 months of ethanol feeding with a 59% decrease (P less than 0.001) in hepatic vitamin A levels, and fibrosis or cirrhosis developed after 24-84 months with a 95% decrease (P less than 0.001). Similarly, hepatic vitamin A levels of rats fed ethanol (36% of total calories) were decreased after 3 weeks (42%, P less than 0.01) and continued to decrease up to 9 weeks. In contrast, vitamin A contents in the kidney and testis were increase 2-3 fold in ethanol-fed rats after 9 weeks. Serum vitamin A and RBP levels were not significantly changed in rats. When dietary vitamin A was increased 5-fold, hepatic vitamin A was again decreased in ethanol-fed rats. When dietary vitamin A was virtually eliminated, the depletion rate of vitamin A from endogenous hepatic storage was 2.5 times faster in ethanol-fed rats than in controls. It is concluded that chronic ethanol consumption decreases hepatic vitamin A, and that some mechanisms other than malnutrition and malabsorption may be involved in this process.