UV light, beta-carotene and human skin - Beneficial and potentially harmful effects

Solar radiation is one of the most important environmental stress agents fo r human skin, causing sunburn, premature skin aging, and skin cancer. Beta- carotene is discussed to protect against photooxidative stress and thus pre vent skin damage. Though beta-carotene has been successfully used against p hotosensitivity in patients with erythropoietic protoporphyria, its benefic ial potential in normal skin is still uncertain. A number of experimental s tudies indicate protective effects of beta-carotene against acute and chron ic manifestations of skin photodamage. However, most clinical studies have failed to convincingly demonstrate its beneficial effects so far. Neverthel ess, intake of oral beta-carotene supplements before sun exposure has been recommended on a population-wide basis. Recent studies on skin cells in cul ture have revealed that beta-carotene acts not only as an antioxidant but a lso has unexpected prooxidant properties. At present, there is an ongoing d ebate on the protective or potentially harmful role of beta-carotene in hum an skin. (C) 2001 Academic Press.