Effects of chronic ethanol and diet treatment on urinary folate excretion and development of folate deficiency in the rat.

Because the folate deficiency of chronic alcoholism has been proposed to result from ethanol-induced effects on metabolism or urinary excretion of folate, the present study was designed to evaluate the role of chronic ethanol-induced urinary folate loss on folate homeostasis in the rat. Male Sprague-Dawley rats were fed nutritionally sufficient liquid diets for 12 wk with or without ethanol, folate and sulfonamide. Urinary folate excretion was increased in ethanol-fed rats consuming folate-containing diets, but not in rats fed folate deficient diets. Consumption of folate-deficient diets led to a rapid decrease in urinary folate excretion, suggesting renal adaptation to conserve folate. Tissue and plasma levels of folate were mostly unaffected by ethanol ingestion in rats fed folate-containing diets. Ethanol treatment did not consistently enhance tissue folate depletion in rats fed folate-deficient diets. The results suggest that in rats consuming diets containing high levels of folate, chronic ethanol ingestion increased urinary folate excretion, but not to a sufficient magnitude to consistently affect folate homeostasis.