An increase in vitamin E requirement induced by high supplementation of vitamin C in rats.

Weanling rats were maintained on purified diets with graded levels of vitamin E at 50, 60, 100, 200, or 500 IU/kg diet; each group was further divided into two subgroups, each with six rats and received vitamin C at 0 or 1.5 g/kg diet. After 1 or 2 months, the determination of antioxidant status showed that the high supplementation of vitamin C at the marginally adequate vitamin E level significantly increased in vitro erythrocyte hemolysis and liver lipid peroxidation, and significantly lowered erythrocyte level of reduced glutathione and plasma level of vitamin E; thus lowering the overall antioxidant potential of the animals. A small increase in vitamin E level counteracted the hemolytic and peroxidative effect of the high supplementation of vitamin C. A greater increase in vitamin E level counteracted the effect of high supplementation of vitamin C in decreasing glutathione level and plasma vitamin E level. These results indicate that the adverse effect of the high supplementation of vitamin C on tissue antioxidant potential may be overcome by increasing the supplementation level of vitamin E, and suggest that vitamin E requirement may be increased with increased vitamin C supplementation.