title: Vitamin A: evidence for its preventive role in human cancer.
abstract: Both the provitamin beta-carotene and natural vitamin A and its derivatives (the retinoids) are being proposed as potential chemopreventive agents. The biochemistry and pharmacology of vitamin A suggest a number of mechanisms whereby carcinogenesis can be affected. Epidemiologic studies have consistently demonstrated an increased relative risk of cancer for people with low vitamin A intake or low-to-normal serum retinol values. Chemoprevention trials in humans are only now beginning. In the interim, daily consumption of vitamin-A-containing foods may be a "prescription" worth following.
mesh_terms: D002338:Carotenoids / Q000627:therapeutic use; D004032:Diet; D006801:Humans; D009369:Neoplasms / Q000517:prevention & control*; D011446:Prospective Studies; D012189:Retrospective Studies; D012306:Risk; D014801:Vitamin A / Q000097:blood / Q000502:physiology / Q000627:therapeutic use; D019207:beta Carotene
chemical_list: D019207:beta Carotene; D014801:Vitamin A; D002338:Carotenoids