Vitamin C bioaccessibility of commercially available dietary supplements: Quantity vs efficiency, does it matter?

Abstract

Knowing the label claims and bioaccessibility of vitamin C supplements is essential for determining daily vitamin C intake. The purpose of the present study was to investigate the bioaccessibility of vitamin C in commercial dietary supplements by an in vitro digestion model. In our study, 17 products were examined, including 2 capsules, 15 tablets (9 of these 15 tablet were effervescent tablets). In most commercial dietary supplements, the measured amounts of vitamin C were very close to or higher than the declared amounts. The average measured vitamin C amount of the products were between 90.3 % and 107.5 % of the declared amount. The in vitro bioaccessibility of vitamin C in dietary supplements was ranged from 4.0 % to 88.0 %. We observed that the bioaccessibility of vitamin C is higher in mono-supplements compared to multi-supplements. Our results showed that the bioaccessibility of dietary supplements was highly variable. Differences in ingredients of dietary supplements may affect the bioaccessibility of vitamin C. Consequently, the ingredients of the vitamin C supplements and the coating technology used are likely to affect supplementation efficiency.