The excretion of vitamin C in human urine and its dependence on the dietary intake

Abstract

PREVIOUS papers from this laboratory have dealt with the application of the titration method with 2: 6-dichlorophenolindophenol to the estimation of vitamin C in various animal materials [Harris and Ray, 1933, 1, 2; Birch et al., 1933; Birch and Dann, 1933; Harris, 1933]. Results on human urines are discussed in the present communication. A principal purpose we had in mind in undertaking this enquiry was to discover whether any relation could be found between urinary loss and the state of nutrition of the individual in respect to vitamin C sufficiency or subnormality. Any such index would obviously be of great value for practical human dietetics.Previous biological work has failed to demonstrate the presence of vitamin C in urine [van der Walle, 1922], but a note just published by Eekelen et al. [1933] mentions, without giving actual data, that the reducing substance in urine is higher in persons using much fruit. METHOD.The micro-method of Birch et al. [1933] was used throughout. The urine to be examined was made acid with trichloroacetic acid (final concentration of latter, 5 %) and titrated from a micro-burette reading to 0 01 cc. against 005 cc. of the indicator, which had been previously standardised against ascorbic acid. Titrations were carried out immediately after, or within a few minutes of, urination, as we found that the titre tended to fall in urine which had been allowed to stand for long. It is essential to carry out the titration rapidly and reach the end-point within about 1 min., otherwise erroneously high values will be caused by phenolic or similar substances in the urine reducing. the indicator slowly. Urines are sometimes encountered which are too dilute to give a satisfactory end-point. If a reading is required for such an individual it is necessary to restrict his fluid intake. The results to be described make it clear that the titration figure bears a genuine relation to vitamin C metabolism, but in expressing our results for convenience in terms of so many mg. of ascorbic acid we wish to. make it clear that it is without prejudice to the question of the invariable specificity or otherwise of the reaction. EXPERIMENTAL.Excretion after large dose. Our most detailed observations were undertaken with the object of obtaining a quantitative picture of the course of excretion of the vitamin after the administration of a single large dose. These results will be

Vitamin C Saturation Levels in the Body in Normal Subjects and in Various Pathological Conditions 1

“…per cc. of urine during the day period (less during the night)-approximately that previously reported by Harris, Ray and Ward (1). . The present paper is concerned with further studies upon the utilization and excretion of vitamin C in conditions associated with vascular damage, hemorrhagic tendencies, as well as in other pathological states.…”

“…The results of these studies (Table I) indicate, 1, that the 24 hour output of vitamin C is usually about 13 to 20 mgm., and that the average is between 0.03 and 0.05 mgm. per cc.…”

“…Besides normal controls, the cases studied included purpura (both thrombocytopenic and symptomatic), acute lupus erythematosus, glomerulonephritis, acute rheumatic fever, rheumatoid arthritis, and jaundice of varied etiology. 1. A test for vitamin C saturation or subclinical deficiency is presented.…”

Critical Remarks on the Determination of Urinary Excretion of Ascorbic Acid

“…In urine, an indophenol reducing substance was demonstrated by 1 van Euler and Klussman (4), van Eekelen et al (5), and Harris et al (6). Harris et al (6), van Eekelen et al (7), and Johnson and Zilva (8) have shown that following the intake of large amounts of ascorbic acid the urinary excretion of reducing substances increases. Application of the reduction reaction to the quantitative determination of ascorbic acid requires that other reducing substances be removed or prevented from reacting by controlling the conditions.…”

Investigation on the seasonal fluctuation of vitamin C excretion in Palestine

“…SINCE Harris et al (1933) first showed the significance of urinary vitamin C excretion, numerous papers have been published on vitamin C excretion by man. Few of these investigations deal with excretion of vitamin C by normal individuals under natural nutritional and climatic conditions.…”