Effects of oral vitamin E and beta-carotene supplementation on ultraviolet radiation-induced oxidative stress in human skin.
BACKGROUND
Ultraviolet radiation (UVR) generates reactive oxygen species in skin that can play a role in skin damage, but reports about the photoprotective properties of oral antioxidant supplements are conflicting.


OBJECTIVE
We examined the ability of 2 lipid-soluble antioxidants, vitamin E and beta-carotene, to reduce markers of oxidative stress and erythema in human skin exposed to UVR.


METHODS
Sixteen healthy subjects took either alpha-tocopherol (n = 8; 400 IU/d) or beta-carotene (n = 8; 15 mg/d) for 8 wk. Biopsy samples before and after supplementation were taken from unexposed skin and skin 6 h after 120 mJ/cm(2) UVR. The effects of supplements on markers of oxidative stress in skin and the minimal erythema dose to UVR were assessed.


RESULTS
Supplementary vitamin E was bioavailable, the plasma concentration increased from 14.0 +/- 0.66 (x +/- SEM) to 18.2 +/- 0.64 mug/mL (P < 0.01), and the skin concentration increased from 0.55 +/- 0.09 to 1.6 +/- 0.19 ng/mg protein (P < 0.01). Supplementary beta-carotene increased plasma concentrations from 1 +/- 0.3 to 2.25 +/- 0.3 mug/mL (P < 0.05), but skin concentrations were undetectable. Before vitamin E supplementation, UVR increased the skin malondialdehyde concentration from 0.42 +/- 0.07 to 1.24 +/- 0.16 nmol/mg protein (P < 0.01), whereas oxidized or total glutathione increased from 9.98 +/- 0.4% to 12.0 +/- 1.0% (P < 0.05). Vitamin E supplementation significantly decreased the skin malondialdehyde concentration, but neither vitamin E nor beta-carotene significantly influenced other measures of oxidation in basal or UVR-exposed skin.


CONCLUSIONS
Vitamin E or beta-carotene supplementation had no effect on skin sensitivity to UVR. Although vitamin E supplements significantly reduced the skin malondialdehyde concentration, neither supplement affected other measures of UVR-induced oxidative stress in human skin, which suggested no photoprotection of supplementation.
McArdle
Frank
F
Department of Medicine, University of Liverpool, Liverpool, United Kingdom.
Rhodes
Lesley E
LE
Parslew
Richard A G
RA
Close
Graeme L
GL
Jack
Catherine I A
CI
Friedmann
Peter S
PS
Jackson
Malcolm J
MJ
D000284:Administration, Oral; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D004890:Erythema / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D019207:beta Carotene / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*
D000975:Antioxidants; D019207:beta Carotene; D014810:Vitamin E