Before revision: Only preformed vitamin A can cause these problems, because the conversion of carotenoids into vitamin A is downregulated when physiological requirements are met; but excessive uptake of carotenoids can cause carotenosis.
After revision: or retinyl estersOnly preformed vitamin A can cause these problems, because the conversion of carotenoids into vitamin A is downregulated when physiological requirements are met; but excessive uptake of carotenoids can cause carotenosis.