|Russell Robert M|
Submitted to: Experimental Dermatology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/1994
Publication Date: N/A
Citation: N/A Interpretive Summary: Beta-carotene is a plant-derived compound which acts as an antioxidant, protecting body tissues from destruction in the course of normal oxidative processes. Varying levels of beta-carotene are found in both the blood and the skin. A study was done to determine whether the ingestion of beta-carotene (either as a single 120-mg dose, or daily 90-mg doses for 23 days) would provide protection against adverse effects on the skin (such as sunburn and tanning) brought about by short-term exposure to ultraviolet (UV) radiation. Beta-carotene levels in the blood increased 2.3-fold whereas skin levels increased only slightly with a single 120 mg beta-carotene dose. Daily supplementation with 90 mg of beta-carotene for 23 days increased blood levels 9-fold and more than doubled the level in skin. When a small area of the arm was exposed to solar- simulated light at 3 times the minimal UV dose that produces redness on the skin, no protective effect of beta-carotene against UV exposure was seen. There was no effect of beta-carotene supplementation on the inten- sity of sunburn resulting from the UV dose; there were no differences in the number of sunburn cells and severity of swelling in skin biopsies taken from subjects before and after beta-carotene ingestion; and there were also no differences compared to subjects who ingested placebo, an inactive substance given as a control. The data suggest that oral beta- carotene supplementation in doses sufficient to increase levels in both blood and skin is unlikely to modify the severity of skin injury following short-term UV exposure.
Technical Abstract: Beta-carotene, a quencher of excited species such as singlet oxygen and free radicals, has been reported to protect against cutaneous photodamage, including sunburn acutely and photocarcinogenesis chronically. The present double blind placebo-controlled study examines the effect of beta-carotene supplementation on the human sunburn response and specifically on the induction of sunburn cells at the time of peak reaction intensity (24 hr) after a single solar-simulated light exposure 3 times the individually determined minimal erythema dose (MED). Administered orally either as a single 120 mg dose to dietarily restricted subjects or for 23 days as a daily 90 mg supplement to subjects on self-selected diets, beta-carotene increased plasma and skin levels of beta-carotene compared to both pretreatment levels and placebo-treated controls, but provided no clinically or histologically detectable protection against a 3 MED sunburn reaction. Thus, these data suggest that oral beta-carotene supplementation is unlikely to modify the severity of cutaneous photodamage in normal individuals to a clinically meaningful degree.