Carotenoids and protection against solar UV radiation

Upon exposure to UV light photooxidative reactions are initiated which are damaging to biomolecules and affect the integrity of cells and tissues. Photooxidative damage plays a role in pathological processes and is involved in the development of disorders affecting the skin. When skin is exposed to UV light, erythema is observed as an initial reaction. Carotenoids like beta-carotene or lycopene are efficient antioxidants scavenging singlet molecular oxygen and peroxyl radicals generated in during photooxidation. When beta-carotene was applied as such or in combination with alpha-tocopherol for 12 weeks, erythema formation induced with a solar light simulator was diminished from week 8 on. Similar effects were also achieved with a diet rich in lycopene. Ingestion of tomato paste corresponding to a dose of 16 mg lycopene/ day over 10 weeks led to increases in serum levels of lycopene and total carotenoids in skin. At week 10, erythema formation was significantly lower in the group that ingested the tomato paste as compared to the control group. No significant difference was found at week 4 of treatment. Thus, protection against UV light-induced erythema can be achieved by ingestion of a commonly consumed dietary source of lycopene. Such protective effects of carotenoids were also demonstrated in cell culture. The in-vitro data indicate that there is an optimal level of protection for each carotenoid.