Why can a high intake of beta-carotene turn skin yellow without causing vitamin A poisoning?

A high intake of beta-carotene does not cause vitamin A poisoning because the body regulates its conversion of beta-carotene into vitamin A through specialized cells in the small intestine. When beta-carotene is consumed in large quantities, the body does not convert all of it into vitamin A; instead, the excess pigment circulates in the bloodstream.1

This accumulation of pigment can lead to carotenemia, a harmless condition characterized by a yellowish or orange skin discoloration, particularly on the palms, soles of the feet, and nose. Unlike vitamin A, which is fat-soluble and can reach toxic levels by being stored in the liver when consumed in excess, carotene is not toxic. The skin discoloration associated with carotenemia is temporary and typically fades once the dietary intake of beta-carotene is reduced and blood levels decline.213