Abstract
- Background
Ultraviolet radiation ($\text{UVR}$) 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.
- Methods
We examined the ability of two lipid-soluble antioxidants, vitamin E ($\alpha$-tocopherol) and $\beta$-carotene, to reduce markers of oxidative stress and erythema in human skin exposed to $\text{UVR}$. Sixteen healthy subjects took either $\alpha$-tocopherol ($n = 8$; $400\text{ IU/day}$) or $\beta$-carotene ($n = 8$; $15\text{ mg/day}$) for 8 weeks. Biopsy samples before and after supplementation were taken from unexposed skin and skin 6 hours after $120\text{ mJ/cm}^2$ $\text{UVR}$. The effects of supplements on markers of oxidative stress in skin and the minimal erythema dose to $\text{UVR}$ were assessed.
- Results
Supplementary vitamin E was bioavailable; plasma concentration increased from $14.0 \pm 0.66$ to $18.2 \pm 0.64\text{ }\mu\text{g/mL}$ ($p < 0.01$), and skin concentration increased from $0.55 \pm 0.09$ to $1.6 \pm 0.19\text{ ng/mg protein}$ ($p < 0.01$). Supplementary $\beta$-carotene increased plasma concentrations from $1 \pm 0.3$ to $2.25 \pm 0.3\text{ }\mu\text{g/mL}$ ($p < 0.05$), but skin concentrations were undetectable. Before vitamin E supplementation, $\text{UVR}$ increased skin malondialdehyde concentration from $0.42 \pm 0.07$ to $1.24 \pm 0.16\text{ nmol/mg protein}$ ($p < 0.01$), whereas oxidized/total glutathione ratio increased from $9.98 \pm 0.4\%$ to $12.0 \pm 1.0\%$ ($p < 0.05$). Vitamin E supplementation significantly decreased skin malondialdehyde concentration, but neither vitamin E nor $\beta$-carotene significantly influenced other measures of oxidation in basal or $\text{UVR}$-exposed skin.
- Conclusions
Vitamin E or $\beta$-carotene supplementation had no effect on skin sensitivity to $\text{UVR}$. Although vitamin E supplements significantly reduced skin malondialdehyde concentration, neither supplement affected other measures of $\text{UVR}$-induced oxidative stress in human skin, which suggested no photoprotection from supplementation.
https://www.sciencedirect.com/science/article/pii/S0002916522036863