Because we had found that ethanol interacts with retinol, we investigated whether it also affects its precursor, beta-carotene. In 14 baboons fed ethanol (50% of total energy) for 2 to 5 yr with a standard amount of beta-carotene (one 200-gm carrot/day), levels of beta-carotene were much higher than in controls fed isocaloric carbohydrate, both in plasma (122.5 +/- 30.9 nmol/dl vs. 6.3 +/- 1.4 nmol/dl; p less than 0.005) and in liver (7.9 +/- 1.1 nmol/gm vs. 1.8 +/- 0.5 nmol/gm; p less than 0.001). Even 20 days after withdrawal of the carrots, plasma beta-carotene levels remained higher in alcohol-fed baboons than in controls (10.1 +/- 3.8 nmol/dl vs. less than 0.1 nmol/dl). Next, the diet was supplemented with beta-carotene beadlets: in four pairs of baboons given a low dose of beta-carotene (3 mg/1,000 kcal), plasma levels were significantly higher in alcohol-fed animals than in controls, even when expressed per cholesterol (although the latter increased with alcohol intake). Seven pairs of animals were given a higher dose (30 mg/1,000 kcal) of beta-carotene for 1 mo, followed, in four pairs, by 45 mg for another month. On cessation of beta-carotene treatment, plasma levels decreased more slowly in the alcohol-fed baboons than in the controls. Percutaneous liver biopsy specimens revealed that liver concentrations of beta-carotene correlated with plasma levels but were higher in the alcohol-fed baboons than in the control baboons, whereas the beta-carotene-induced increase in liver retinoids was lower (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)