With the number of diagnosed melanomas doubling in the U.S.A. since 1973, protection of the skin against ultraviolet radiation damage has become a priority health issue. Beta -carotene (a precursor of vitamin A) has been widely used as an oral sun protectant with few studies into its effectiveness; however, new research by Stahl et al. in The American Journal of Clinical Nutrition provides clinical evidence that beta-carotene modifies sunburn damage, and vitamin E may add to that effect. Sunburn intensity was significantly reduced in subjects who took vitamin supplements over a 12 week period while being exposed to UV radiation.
All of the 22 volunteers for the study were healthy, fair-skinned nonsmokers who were divided into two groups: one received 25 mg. mixed carotenes daily, and the other 25 mg mixed carotenes plus 335 mg vitamin E combined daily. Before supplementation, the subjects' individual skin reactions to UV exposure were measured by inducing a mild sunburn using a blue-light solar simulator; hence, the two groups of subjects acted as their own controls. Over the 12-week period of vitamin supplementation, the skin on their backs was irradiated with UV light every four weeks at gradually increasing levels and the resulting mild sunburn reaction was measured using chromatometry. A significant reduction in sunburn intensity was observed in both groups; for instance, at week 8 of supplementation the subjects in the "carotene only" group had a 29% less intense sunburn response than they had experienced during the control period. The "carotene plus E" group had an even milder response which, though not statistically significant, could indicate an additional protective effect against sunburn for vitamin E.
Previous studies of the sun-protective effect of carotenes have been of much shorter duration. Also, in this study reduction of sunburn reaction was greater toward the conclusion of the 12 weeks of supplementation than at the beginning. The authors conclude that the duration of supplementation with carotenes and vitamin E is probably of greater consequence in protecting against sunburn than the dosage.
Stahl, W et al. Carotenoids and carotenoids plus vitamin E protect against ultraviolet light-induced erythema in humans. Am J Clin Nutr 2000;71:795-798.
For more information please contact Dr. Wilhelm Stahl at: wilhelm.stahl@uni-duesseldorf.de
This media release is provided by The American Society for Clinical Nutrition, to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor.
Journal
American Journal of Clinical Nutrition