A Study on the Relation and Adjustment of Blood Plasma Level and Urinary Excretion of Ascorbic Acid to Intake

Abstract

Twenty-four college women served as subjects in a study of the relation and adjustment of blood plasma level and urinary excretion of ascorbic acid to intake. The data were collected in 4 experimental units of 6 subjects each. Two units were studied in the summer and two in the winter. The experimental plan provided for intakes of 50, 75, and 100 mg of ascorbic acid, augmented by that of a low ascorbic acid diet, in increasing and decreasing order in sequences which differed for each of the 6 subjects of a unit. The units were replicates. The adjustment period at each intake was 12 days. Blood plasma ascorbic acid analyses were made at stated intervals and urinary excretion analyses were made daily on 24-hour collections. Both blood plasma and urinary excretion values of ascorbic acid, as criteria, indicated a carry-over effect of the previous intake which was still evident at the end of 12 days. “Equilibrium” values were statistically estimated from the data and, based on the trends shown, indicate expected values at “equilibrium” had it been reached. Retention calculated both from experimental data and estimated “equilibrium” values shows for these subjects a “utilization” close to 1 mg per kilogram of body weight. No difference in requirement due to season is shown by the response criteria of this series of experiments.