Ann N Y Acad Sci. 2004;1031:184-94.
Oral supplementation with all-Rac- and RRR-alpha-tocopherol increases
vitamin E levels in human sebum after a latency period of 14-21 days.
Ekanayake-Mudiyanselage S, Kraemer K, Thiele JJ.
Department of Dermatology, Northwestern University, 303 East Chicago Avenue,
Chicago, IL 60611, USA.
In human skin, highest alpha-tocopherol levels are found in facial sebum. We
hypothesized that the bioavailability of vitamin E in human skin is, at least
in part, dependent on sebaceous gland secretion. To test this, 24 volunteers
were subjected to a randomized daily supplementation with either 400 mg
RRR-alpha-tocopheryl acetate (RRR-alpha-toc) or 400 mg all-rac-alpha-tocopheryl
acetate (all-rac-alpha-toc) for 14 days. Fasting blood samples, facial sebum
samples, and lower-arm skin-surface lipids (SSL) were taken at time-points
between 0-21 days. Samples were analyzed by HPLC for alpha-tocopherol and
squalene concentrations. Increased serum alpha-tocopherol levels were
detectable as early as 12 h after supplementation of RRR-alpha-toc or
all-rac-alpha-toc and peaked on day 7. No significant changes were observed in
lower-arm SSL. Remarkably, while unchanged until day 14, alpha-tocopherol sebum
levels were increased on day 21 in both the RRR-alpha-toc and the
all-rac-alpha-toc group by 87% and 92%, respectively. With respect to dietary
supplementation of vitamin E and its bioavailability in human skin, these
results suggest that (1) sebaceous gland secretion is a relevant delivery
mechanism; (2) the bioavailabilities of RRR-alpha-toc and the all-rac-alpha-toc
are similar; and (3) significant accumulation requires a daily supplementation
period of at least 2-3 weeks.