Influence of dietary carotenoids on radical scavenging capacity of the skin and skin lipids.

Nutrition rich in carotenoids is well known to prevent cell damage, premature skin aging, and skin cancer. Cutaneous carotenoids can be enriched in the skin by nutrition and topically applied antioxidants have shown an increase in radical protection after VIS/NIR irradiation. In this paper, it was investigated whether orally administered carotenoids increase the radical scavenging activity and the radical protection of the skin using in vivo electron paramagnetic resonance spectroscopy and the skin lipid profile was investigated applying HPTLC on skin lipid extracts. Furthermore, in vivo Raman resonance spectroscopy was used to measure the cutaneous carotenoid concentration. A double blind placebo controlled clinical study was performed with 24 healthy volunteers, who have shown a slow but significant and effective increase in cutaneous carotenoids in the verum group. The enhancement in carotenoids increases the radical scavenging activity of the skin and provides a significant protection against stress induced radical formation. Furthermore, the skin lipids in the verum group increased compared to the placebo group but only significantly for ceramide [NS]. These results indicate that a supplementation with dietary products containing carotenoids in physiological concentrations can protect the skin against reactive oxygen species and could avoid premature skin aging and other radical associated skin diseases.