Beta-carotene is found in vegetables and other foods. Its antioxidant effects were once thought to have beneficial effects such as chemoprevention.
Beta-carotene serves as provitamin A (with conversion by beta-carotene 15,15'-monooxygenase).
It is safe at levels seen with a normal diet.
It can be toxic if excessive doses are taken, especially for a long period of time. Adverse effects in high doses may include:
(1) carotenemia with carotenoderma
(2) vitamin A toxicity
(3) potentially toxic metabolites causing mitochondriotoxicity
(4) potential hepatotoxicity that is increased by alcohol abuse
(5) possible increased risk of lung cancer in smokers
