Estimated Dietary Intake, Urinary Excretion and Blood Vitamin C in Women of Different Ages

Abstract

The nutritional status of 569 women (68 of whom were studied twice) from 5 locations in the North Central states has been examined with respect to vitamin C. Whole blood, plasma or serum concentrations of vitamin C were related to the estimated dietary intake. Mean blood values for the state samples varied from 0.76 ± 0.463 to 1.20 ± 0.553 mg of vitamin C per 100 ml. Basal excretion of vitamin C and excretion after a 400 mg load dose were obtained from 135 of the subjects in Iowa, Michigan and South Dakota. At low intakes, basal urinary excretion of vitamin C exhibited random variation, but when the average daily intake exceeded 1.1 mg per kilogram of body weight, the relation of basal excretion to intake was nearly linear. Beyond intakes of 1.25 mg per kilogram of body weight, the slope of the mean line of load dose excretion was less steep than at lower intakes. Age did not influence either the mean intake of vitamin C or its mean concentration in the blood of women participating in this study. Among Iowa women, vitamin C intakes of 1.1 mg or more per kilogram of body weight per day were associated with (1) blood values above 0.8 mg % in 89% of the cases, (2) basal urinary excretions of more than 15 mg per day in 80% of the cases, and (3) excretions of more than 115 mg per 24 hours after a load dose of 400 mg in 84% of the cases. Therefore, an ascorbic acid intake of 1.1 mg or more per kilogram of body weight from self-selected diets provides women with apparently satisfactory amounts of this vitamin. Individual intakes below 1.1 mg per kilogram of body weight occurred frequently in the populations examined.