Nutrition and alcohol neurotoxicity.

Neurological complications of alcoholism such as Wernicke-Korsakoff syndrome and polyneuropathy often originate from interactive factors involving direct nervous system toxicity of ethanol and nutrient deficiencies associated to heavy drinking. Not all patients are equally susceptible to these disorders and a genetic predisposition to thiamine deficiency has been described in subjects with Wernicke's encephalopathy. At moderate alcohol dosages, nutrient abnormalities may be marginal, inducing no obvious manifestations until other neurotoxic agents are absorbed. Examples are presented illustrating the interaction of ethanol and styrene on brain glutathione metabolism in rats, and cases of methanol poisoning in alcoholics. In these patients, ethanol-induced folate deficiency can potentiate visual toxicity of methanol due to impairment of the folate-dependent pathway involved in formate detoxication. The notion that nutritional deficiencies and ethanol toxicity may act synergistically in the nervous system outlines the importance of adequate nutritional strategies in the treatment of alcoholism and also indicates that methodological flaws may result during experimental studies from failure to control for nutritional variables.