Physiological Availability of the Vitamins: V. The Effect of Copper on Extra Dietary Ascorbic Acid

Abstract

The addition of 7 mg. of cooper to a homogenized mixture of a day’s ration and incubation of this mixture for a period of 6 hours at 37°C. resulted in a small but real destruction of the ascorbic acid present. ent. Since no more vitamin was destroyed in the presence of added ascorbic acid (200 mg.), this destruction is regarded as absolute. The factor primarily responsible for the marked loss of ascorbic acid in a homogenized dietary mixture is ascorbic acid oxidase. The addition of extra copper to such a mash (unblanched) failed to produce markedly greater destruction of vitamin C. This would seem to indicate that ascorbic acid oxidase is a specific enzyme and not simply a loose complex of copper with protein of unspecific nature. Human availability studies have indicated that in the digestive tract ascorbic acid and copper in the quantities taken, 200 mg. and 7 mg., respectively, are not incompatible.