EFFECTS OF DIETARY NIACIN AND RIBOFLAVIN ON VOLUNTARY INTAKE AND METABOLISM OF ETHANOL IN RATS

The effects of dietary deficiency and excess of niacin and riboflavin on voluntary drinking of 10% (vol/vol) ethanol were studied in male rats. The effectiveness of dietary deficiency and excess of both niacin and riboflavine on tissue levels of these vitamins was demonstrated by measurements of urinary N1-methylnicotinamide and blood glutathione reductase (EC 1.6.4.2) activity. A high-niacin diet containing 75 mg niacin/kg food decreased ethanol intake by about 36% compared to the control diet containing 15 mg niacin/kg. Niacin or riblflavine deficiency and a high-riboflavine diet containing 40 mg riboflavine did not significantly affect ethanol drinking. Changes in dietary levels of niacin or riboflavine did not influence ethanol elimination rate or levels of blood acetaldehyde during ethanol oxdiation. Blood acetaldehyde was not responsible for the decreased ethanol intake of rats fed with a high-niacin diet. The increased ethanol intake caused by dietary deprivation of B-vitamin complex found in earlier studies is not a result of deficiency of niacin or riboflavine, but niacin may be involved in the decrease in ethanol drinking, which follows dietary B-vitamin complex supplementation.