Vitamin C Nutriture Has Little Short-Term Effect on Vitamin E Concentrations in Healthy Women

Abstract

To determine whether the postulated sparing effect of vitamin E by ascorbic acid (AA) is important for human nutrition, we studied vitamin E status in 20 healthy pre-menopausal women (age 20–43 y) with high or low vitamin C intakes for 6 wk in a live-in metabolic unit. The experimental diet contained no fruits and vegetables and provided 5 mg/d of AA (Recommended Dietary Allowance = 60 mg/d), 3 mg/d of α-tocopherol (RDA = 10 mg/d) and 42 g/d of tocopherol-stripped safflower oil to increase the vitamin E requirement. Half of the subjects received a daily AA supplement of 495 mg (high AA group). A biochemical ascorbate deficiency was attained in the low AA group as indicated by plasma AA concentrations that reached the lower limit of normal by study d 15. Oral doses (20 mg) of hexadeuterated RRR-α-tocopherol acetate (d6-αT) were given daily to all subjects on d 15–21. Measures of vitamin E status included d6-αT and unlabeled α-tocopherol concentrations in plasma, platelets, buccal cells and adipose. The levels of unlabeled α-tocopherol decreased over time in plasma and platelets and were unchanged for buccal cells and adipose, but were not significantly affected by AA intake. Likewise, the rise and fall of plasma and platelet d6-αT, and measures of lipid peroxidation, were not affected by AA intake. Although vitamin C nutriture did not significantly affect vitamin E status within the 6-wk time period of this experiment, further study of this question is warranted, because some of the present results indicate a trend toward sparing of tissue tocopherol by high AA intake.