Failure of a massive single oral dose of vitamin A to prevent deficiency.

Preschool children maintained on low and moderate carotene diets were given a single oral dose of 50,000 μg vitamin A palmitate. On the low carotene diet, xerosis was observed in 8 weeks' time in the control group of children, and in 10 weeks' time in the children given the load of vitamin A. Statistical differences in serum vitamin A values between the groups were not of significance after 18 weeks. Children on a moderate carotene diet did not benefit from the loading dose of vitamin A.