Effect of vitamin B6 on leucine-induced changes in human subjects

Distrubances in the tryptophan-niacin pathway seen in endemic pellagra among sorghum eaters have been ascribed to high dietary intake of leucine. Vitamin B6 plays an important role in several steps of this pathway. Therefore, studies on possible metabolic interrelations between excess dietary leucine and vitamin B6 were undertaken in normal healthy human subjects. The results indicated that vitamin B6 could successfully counteract the effects of leucine on quinolinic acid excretion in urine, and on in vitro nicotinamide nucleotide synthesis by erythrocytes, and also could correct the abnormalities of 5-hydroxytryptamine metabolism induced by excess leucine. These observations suggest that vitamin B6 nutritional status may have a contributory role in the pathogenesis of endemic pellagra.