Effects of chronic alcohol feeding on thiamin status: biochemical and neurological correlates

The effects of chronic alcohol feeding on thiamin status are controversial; both adverse and beneficial effects have been reported. In order to study these effects, rats and baboons were pair-fed liquid diets containing thiamin in excess of dietary requirements and either ethanol (rats 36%, baboons 50% of total calories) or the identical diet with ethanol substituted isocalorically by carbohydrate. In the rat, chronic alcohol feeding for up to 6 months had no effects on tissue thiamin measured by transketolase assay, thiamin pyrophosphate effect, or bioassay with Ochromonas danica. Shuttle box avoidance learning in rats was impaired in animals rendered thiamin deficient but not in animals fed control or alcohol-containing liquid diets. In baboons, chronic alcohol feeding for up to 3 yr had no effects on blood levels of thiamin or on urinary excretion of thiamin. Thus, chronic alcohol feeding along with nutritionally supplemented diets does not appear to significantly affect thiamin status.