RESUMEN
Topical supplementation represents an attractive approach to mitigate environmentally induced deficiencies of skin vitamin E (alpha-tocopherol). We report here the impact of natural sunlight on stratum corneum (SC) vitamin E and also compare the effectiveness of dietary supplementation to topical application as a way to increase vitamin E in the superficial layers of the SC. The effects of natural sunlight, 30 minutes of midday sunlight, were measured on two separate occasions. Vitamin E in the surface layers of the SC was measured by HPLC after ethanol extraction. Under these relevant conditions, vitamin E in the superficial SC was reduced in a dose-dependent manner by 50-65%. In a followup study, panelists entered into a randomized, double-blind, vehicle-controlled study. In this study, one group washed their skin once daily for one minute with a commercially available body wash containing 0.15% vitamin E and 0.10% vitamin E acetate, while the second group used a body wash without vitamin E but also supplemented their diet with 400 IU alpha-tocopherol (18 x RDI). Not surprisingly, only dietary supplementation increased serum vitamin E (approximately twofold). Although both treatment modalities increased SC vitamin E, topical delivery was significantly more effective (53-fold vs baseline) than dietary delivery (eightfold vs baseline). Moreover, only topical delivery increased SC vitamin E acetate (19-fold vs baseline). The results reported here indicate that vitamin E in the superficial layers of the SC is depleted readily by even a brief exposure to sunlight and that use of a vitamin E body wash can substantially increase the vitamin E in this superficial layer more effectively than dietary supplementation.