Skin aging is a multifaceted biological process influenced by both intrinsic factors, such as genetics and hormonal changes, and extrinsic factors like ultraviolet (UV) radiation, environmental pollution, and lifestyle choices. This complex process results in a progressive decline in the structural and functional integrity of the skin. Understanding these nuances offers critical insights into the vulnerabilities and adaptive mechanisms of aging skin, forming the basis for targeted preventive and therapeutic approaches.
Given the intricate nature of skin aging, there is a growing interest in naturally occurring compounds that can offer protective effects. Carotenoids, which are natural pigments found in fruits and vegetables, have emerged as promising candidates due to their significant antioxidant and anti-inflammatory properties. Compounds like β-carotene, lycopene, lutein, and astaxanthin have demonstrated protective effects against oxidative damage, UV-induced photoaging, and inflammation when applied both topically and through diet. This review article, based on a comprehensive systematic review, aimed to analyze the protective mechanisms of carotenoids against skin aging, clarify the cellular pathways through which they exert their effects, and highlight their translational potential in anti-aging skincare.
Key Findings
The review highlighted several key protective roles of carotenoids in mitigating skin aging:
• Anti-oxidative Activity: Carotenoids play a crucial role in maintaining cellular redox balance by actively scavenging reactive oxygen species (ROS) and reactive nitrogen species (RNS), reducing lipid peroxidation, and enhancing the activity of endogenous antioxidant enzymes like superoxide dismutase (SOD) and glutathione peroxidase (GPx). They also upregulate transcription factors such as Nrf2, thereby indirectly enhancing cellular resilience against oxidative insults.
• Anti-inflammatory Properties: Carotenoids suppress chronic skin inflammation and associated tissue degradation by downregulating pro-inflammatory signaling pathways, including NF-κB and MAPK, which reduces the expression of cytokines such as TNF-α, IL-6, and IL-1β. They also inhibit enzymes like COX-2 and LOX, which are involved in the synthesis of pro-inflammatory eicosanoids, and facilitate the phenotypic switch from pro-inflammatory M1 to anti-inflammatory M2 macrophages.
• Photoprotection: Carotenoids like β-carotene, lutein, lycopene, and astaxanthin absorb specific wavelengths of UV radiation, dissipating absorbed energy as harmless heat and functioning as biological filters. They provide indirect photoprotection by neutralizing UV-induced ROS, which helps limit DNA photodamage, oxidative stress, and inflammation related to photoaging. Regular consumption and topical application of carotenoids increase their concentration in the skin, enhancing resistance to UVB-induced erythema and reducing markers of inflammation.
• Collagen and Extracellular Matrix (ECM) Support: Carotenoids enhance fibroblast activity and promote collagen synthesis, particularly type I collagen, by activating TGF-β signaling. They also inhibit matrix metalloproteinases (MMPs), such as MMP-1 and MMP-9, which break down structural proteins, thus helping to preserve skin elasticity and dermal density.
• Skin Hydration and Elasticity: Carotenoids indirectly support skin hydration by regulating aquaporins (AQPs), especially AQP3, which are crucial for water and glycerol transport in the epidermis. They also boost hyaluronic acid (HA) production by enhancing fibroblast viability and diminishing inflammatory mediators that inhibit HA synthase. This leads to improved skin hydration and turgor.
• Systemic and Neurological Benefits: Beyond skin health, carotenoids influence systemic immune function by promoting antibody production and modulating macrophage activity. They also exhibit neuroprotective and mood-stabilizing effects, potentially linking oxidative balance and psychological well-being to skin health through the gut–brain–skin axis. Additionally, they demonstrate metabolic regulation, including antilipidemic and antiglucemic properties, indirectly benefiting skin health by improving systemic homeostasis.
• Bioavailability: The absorption of carotenoids is enhanced by dietary fats, particularly unsaturated fatty acids (UFAs), which promote micelle formation in the small intestine. Food processing methods like steaming can also improve bioavailability. The gut microbiota also plays a fundamental role in carotenoid bioconversion and intestinal uptake.
• Controversies: Despite their benefits, debates persist regarding the ideal dosage and delivery method for carotenoids in skincare. Under certain conditions, especially at high concentrations, carotenoids may exhibit pro-oxidative effects. Their effectiveness as photoprotectors and their specific role in reducing skin cancer risk, particularly photocarcinogenesis, remain uncertain and require further empirical evidence.
Conclusion
The future implications of this research are substantial. Integrating carotenoid-rich nutrition with evidence-based cosmeceutical applications and comprehensive lifestyle interventions—such as regular physical activity, stress reduction, adequate sleep, and microbiome modulation—emerges as a holistic and powerful strategy for promoting healthy skin aging. Optimizing carotenoid bioavailability through unsaturated dietary fats, probiotics, and advanced delivery systems (e.g., nanoemulsions, liposomes) can further enhance their protective effects, especially in vulnerable populations. Carotenoids represent a scientifically validated, safe, and versatile class of compounds that can be strategically leveraged to prevent premature skin aging, enhance repair processes, and maintain cutaneous health. However, continued research is crucial to clarify optimal dosages, delivery methods, long-term safety, and their precise role in chemoprevention, ultimately facilitating the creation of personalized nutritional and dermocosmetic strategies for anti-aging skincare.
Link to the study: https://www.mdpi.com/2072-6643/17/16/2596
