The outermost layer of skin – the epidermis – is composed of keratinocytes in various levels of maturity, containing different amounts of melanin. These cells create the largest physical barrier to protect the body from outside assaults. Often referred to as the body’s largest organ, this layer of the skin possesses a multitude of functions. The melanin, specifically, protects the deeper layers of skin from penetrating ultraviolet photons, scavenges free radicals that may damage DNA, and contains antimicrobial activity
Damage to keratinocytes from excessive sunlight exposure initially elicits an inflammatory response classically known as sunburn. Further exposure induces apoptosis of keratinocytes, followed by a fervent rebuilding of cells to form a more protective barrier. However, this latter response leads to the characteristic skin thickening seen in individuals frequently exposed to sunlight. Exposure to UV radiation also encourages free radical production and oxidative damage to cells and their DNA, accentuating the DNA damage induced directly by UV photons
Various nutrients have been found to be helpful in repairing keratinocytes and preventing further damage to skin that has been already marred from sunlight. Plant polyphenols have an extraordinary array of benefits for sun-damaged skin, including anti-inflammatory, immunomodulatory and antioxidant properties. In one study that followed standard photocarcinogenesis protocolsoral administration of green tea polyphenols resulted in significant protection from skin tumorigenesis and an inhibition of UV radiation-induced cutaneous edema, erythema, and bi-fold skin thickness. Additionally, green tea polyphenols were able to significantly reduce free radical production and damage. Clearly, plant polyphenols – such as those found in green tea extract, olive fruit extract, grape seed extract and resveratrol – are highly beneficial for sun-damaged skin.
Individual micronutrients may also play an important role in overall skin health. Vitamin A, known to be a powerful antioxidant, is a naturally occurring constituent of the epidermis and is involved in cell differentiation and turnover. Overexposure to sunlight will quickly deplete the keratinocytes of vitamin A, leaving them more prone to oxidative damage from UV radiation.3 Vitamin C also plays a contributory role in reducing initial inflammation from UV radiation, and is significantly involved in the healing process. This vitamin aids in the synthesis, maturation, secretion and degradation of collagen, the structural protein found in deep skin layers. Collagen is damaged by frequent or excessive exposure to sunlight and results in signs of early aging, including wrinkles, fine lines, and loss of elasticity. Vitamin C will help to rebuild collagen and prevent the aging effects associated with sun-damaged skin.
When it comes to sun exposure, it appears that moderation is the key, with the best way to protect the skin from excessive UV radiation is by limiting your exposure to the sun. Yet, there are ample reasons that drive everyone to get outside and enjoy some of those rays. While no nutrient will completely turn back the clock on the effects sunlight has on skin health, these nutrients mentioned here do offer some much needed skin protection.
For a further look at skin health, please listen to our Clinical Rounds from February 9, 2011, The Clear Skin Diet, with Valori Treloar, MD.
Related DFH products: H-S-N Complex & Resveratrol Synergy