182 JOURNAL OF COSMETIC SCIENCE ■ Unexposed Sun Exposed 50.00 * * .-.. 40.00 E J;! 30.00 0 E a. 20.00 w 10.00 0.00 August October Figure 1. Affect of 30-minute exposure to natural sunlight on vitamin E in the superficial layers of the stratum corneum. The data represent the mean ± standard error of the mean. In August, sixteen subjects completed the study, whereas fourteen completed the study in October(* = p 0.05). 0.05 ). In contrast to vitamin E, the amount of vitamin E acetate in the superficial SC was not affected by sunlight exposure (data not shown). Erythema was not observed in either study. TOPICAL VERSUS DIETARY SUPPLEMENTATION The results of supplementing the diet with 400 IU a-tocopherol for 11 days or washing the skin once daily with the vitamin E body wash for nine days are shown in Figures 2 and 3. As can be seen (Figure 2), both groups started the study with equivalent serum vitamin E (p � 0.05) levels. Vitamin E acetate was not detected in the serum of either group (data not shown). Additionally, only the dietary supplemented group showed an increase in serum vitamin E levels from 24.3 ± 1.5 to 45.3 ± 3.3 µmoles/liter (Figure 2). In contrast to these results, both treatment modalities increased vitamin E in the superficial SC (Figure 3a, p ::5 0.001). In the group using the vitamin E body wash, surface vitamin E increased more than 50-fold, from 5 ± 2 to 267 ± 15 pmoles/cm2• The increase in surface vitamin E for the subjects taking the dietary supplements was much more modest, increasing eightfold, from 9 ± 3 to 79 ± 18 pmoles/cm2• Indeed, topical supplementation was nearly 300% more effective than dietary supplementation (267 ± 15 vs 79 ± 18 pmoles/cm2, p ::5 0.001) in terms of increasing SC vitamin E. However, since vitamin E is not stored within the skin as an ester, only topical supplementation increased the vitamin E acetate in the superficial SC from 1 ± 1 to 157 ± 28 pmoles/cm2 (Figure 36).

VITAMIN E DELIVERY BY SKIN CLEANSER 183 ■ Pre-treatment D Post-treatment 100 ns 80 0 ns E *** 60 w +l 40 E :J ... 20 m en 0 Dietary Group Topical Group Figure 2. Serum vitamin E levels before and after topical and dietary supplementation. The data represent the mean ± standard error of the mean (*** = p 0.001 ns = p ;;::= 0.05 ). DISCUSSION We observed in two separate trials that a 30-minute exposure to suberythemal levels of natural sunlight reduced vitamin E in the superficial layers of the SC by 50-65% (Figure 1), depending on the dose of UVR. Thiele et al. (7) reported a similar reduction (45%) following exposure of subjects to a suberythemal (0. 7 5 MED) dose of solar-simulated UVR. The similarity of results is quite remarkable considering the differences in radia­ tion sources (solar-simulated versus natural sunlight) and SC sampling (tape stripping versus ethanol extraction). Additionally, it should be noted that preliminary experiments indicate that the ethanol extraction procedure samples the upper five to seven layers of the SC (unpublished results). Although vitamin E is sensitive to photodegradation (26), we believe the losses observed in these studies resulted from the reaction between vitamin E and the lipid hydroper­ oxides formed as a consequence of UVR exposure (7,21,27,28). Taken together, the results reported here and by others (7 ,28) clearly show that vitamin E in the superficial layers of the SC is readily depleted by even a modest exposure to sunlight. The impli­ cation of this result is obvious: sun exposure can create a functional deficiency of vitamin E, leaving the stratum corneum lipids less protected from free radical attack. A similar effect (i.e., UV-induced functional deficiency) was observed by Wang et al. (29) and Sorg et al. (30) for cutaneous vitamin A. In addition to UV-induced depletion, several other extrinsic factors may also create a functional deficiency of this key protective molecule in the skin. For example, Rhie et al. (6) reported that the concentration of u-tocopherol was 56% lower in the epidermis of