Interaction of erythorbic acid with ascorbic acid catabolism

After a vitamin C depletion period of 12 days supplementing erythorbic acid (50 mg/day/kg bodyweight) over 16 days significantly accelerated the catabolism of a newly ingested tracer dose of (1-14C) ascorbic aicd in guinea pigs in comparison to animals supplemented with ascorbic acid (5 mg/day/kg bodyweight), but this effect of erythorbic acid could not be normalized by additional supplementation with ascorbic acid. Half-lives for (1-14C) ascorbic acid (50% of the dose excreted) were drastically reduced from 97 h to 50 h and 59 h, respectively. Also figures on the retention of radioactivity showed the availability of ascorbic acid to be reduced. This is in accordance with the significant reduction in size of ascorbic acid bodypool, and in weight gain in the groups receiving erythorbic acid, or erythorbic and ascorbic acids. The bioavailability was calculated to be strongly depressed to nearly 50% of the total ingested biologically active material (ascorbic plus erythorbic acids), assuming erythorbic acid to have only one-twentieth of the biological activity of ascorbic acid.