Role of ingestible carotenoids in skin protection: A review of clinical evidence.

Carotenoids, a class of phytonutrients, have been well established to boost skin's innate resistance against ultraviolet (UV) B-induced erythema (sunburn). Many of the published clinical studies thus far have focused on the measurement of erythema as the primary clinical indicator of skin protection against UVB radiation. More recent studies have shown that carotenoid supplementation provides even more skin protection than previously shown as new clinical and molecular endpoints beyond UVB-induced erythema have been reported. These recent studies have demonstrated that carotenoids also provide photoprotection against UVA-induced pigmentation and inhibit molecular markers of oxidative stress such as intercellular adhesion molecule 1, heme oxygenase-1, and matrix metalloproteinases 1 and 9. This article provides a comprehensive review of the published clinical evidence on skin benefits of carotenoids in the last five decades and indicates new perspectives on the role of ingestible carotenoids in skin protection.