The instability of vitamin A alcohol relative to vitamin A acetate has been studied in vivo and in vitro. Vitamin A alcohol is more unstable than vitamin A acetate in human gastric and duodenal juice and in rats' stomachs and intestines and is more marked at lower pH levels and in rats' stomachs. Alpha tocopherol improved the absorption curve of vitamin A alcohol in man by protecting it in gastric and duodenal juice. This protective effect could not be demonstrated in the rat. |