Do We Utilize Our Knowledge of the Skin Protective Effects of Carotenoids Enough?

Abstract

Due to their potential health-promoting effects, carotenoids have drawn both scientific and public attention in recent years. The primary source of carotenoids in the human skin is diet, mainly fruits, vegetables, and marine product, but they may originate from supplementation and topical application, too. In the skin, they accumulate mostly in the epidermis and act as a protective barrier to various environmental influences. Namely, the skin is exposed to numerous environmental factors, including ultraviolet radiation (UVR), air pollution, and smoking, that cause oxidative stress within the skin with consequent premature (extrinsic) aging. UVR, as the most prominent environmental factor, may cause additional detrimental skin effects, such as sunburn, DNA damage, and skin cancer. Therefore, photoprotection is the first line intervention in the prevention of premature aging and skin cancer. Numerous studies have demonstrated that carotenoids, particularly β-carotene, lycopene, lutein, and astaxanthin, have photoprotective effects, not only through direct light-absorbing properties, but also through their antioxidant effects (scavenging reactive oxygen species), as well as by regulation of UV light-induced gene expression, modulation of stress-dependent signaling, and/or suppression of cellular and tissue responses like inflammation. Interventional studies in humans with carotenoid-rich diet have shown its photoprotective effects on the skin (mostly by decreasing the sensitivity to UVR-induced erythema) and its beneficial effects in prevention and improvement of skin aging (improved skin elasticity and hydration, skin texture, wrinkles, and age spots). Furthermore, carotenoids may be helpful in the prevention and treatment of some photodermatoses, including erythropoietic protoporphyria (EPP), porphyria cutanea tarda (PCT) and polymorphous light eruption (PMLE). Although UVR is recognized as the main etiopathogenetic factor in the development of non-melanoma skin cancer (NMSC) and melanoma, and the photoprotective effects of carotenoids are certain, available studies still could not undoubtedly confirm the protective role of carotenoids in skin photocarcinogenesis.

High‐energy visible light at ambient doses and intensities induces oxidative stress of skin—Protective effects of the antioxidant and Nrf2 inducer Licochalcone A in vitro and in vivo

“…β‐Carotene degradation by VIS irradiation (400‐800 nm, 24.6 J/cm 2 ) of human skin biopsies was reduced by 22% by pretreatment with a formulation containing 3% niacinamide; addition of 0.5% dl‐α tocopherol yielded protection by 65%, which was attributed to the antioxidant function of the vitamins . As suppression of lipid peroxidation was demonstrated for LicA in several biological systems and is well established also for carotenoids, we postulate this mode of action also for the instant carotenoid stabilizing effect of LicA found in our in vivo study. Since the effector phase of Nrf2 activation is considered time‐dependent, its involvement in the reactions of the viable skin layers remains to be elucidated in future studies.…”

“…Blue light photon ROS production efficacy corresponds to 25% of UVA in human keratinocyte mitochondria . ROS detoxification in skin is achieved by low molecular weight antioxidants, such as Vitamins C and E, and carotenoids like β‐carotene, as well as by enzymes and antioxidant proteins, many under the control of nuclear factor erythroid 2‐related factor 2 (Nrf2), the master regulator of cellular redox signaling and antioxidant defenses . Carotenoids are photoprotective, lipophilic plant‐derived pigments with highest concentration in the superficial stratum corneum (SC) and aggregation at skin surface .…”

“…19 ROS detoxification in skin is achieved by low molecular weight antioxidants, such as Vitamins C and E, and carotenoids like β-carotene, as well as by enzymes and antioxidant proteins, many under the control of nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of cellular redox signaling and antioxidant defenses. 20,21 Carotenoids are photoprotective, lipophilic plant-derived pigments with highest concentration in the superficial stratum corneum (SC) and aggregation at skin surface. 22,23 Carotenoids mainly exhibit absorbance maximum at wavelengths in the range of visible light 21 and are rapidly degraded by blue light radiation in human skin ex vivo 24 and in vivo, indicating ROS formation.…”

“…20,21 Carotenoids are photoprotective, lipophilic plant-derived pigments with highest concentration in the superficial stratum corneum (SC) and aggregation at skin surface. 22,23 Carotenoids mainly exhibit absorbance maximum at wavelengths in the range of visible light 21 and are rapidly degraded by blue light radiation in human skin ex vivo 24 and in vivo, indicating ROS formation. 25 However, endogenous restoration takes up to 24 hours.…”

The Benefits and Risks of Certain Dietary Carotenoids that Exhibit both Anti- and Pro-Oxidative Mechanisms—A Comprehensive Review

“…Several other carotenoids have been discussed as possible beneficial antioxidants in the skin, including lycopene, astaxanthin, lutein and, to some extent, such benefits for the skin seem likely [113,114]. Perhaps the most exciting claims concern zeaxanthin and skin melanomas [115] and earlier studies with fucoxanthin.…”