Although sunlight provides us with necessary health benefits, (Vitamin D for instance) prolonged and unprotected sun exposure can have several detrimental effects, including premature aging of the skin and the development and progression of skin cancer.1
For many years, the majority of research on the effects of sun exposure has been focused on the ultraviolet (UV) part of sunlight, ultraviolet B (UVB) and ultraviolet A (UVA). However, UV radiation only accounts for approximately 7% of the sun’s energy,2 which brings to light the need to consider the effects from other parts of the sunlight spectrum.
Infrared A (IRA) has been positively identified as a damaging environmental factor to skin and has shown to alter the gene expression of skin cells at multiple points,3 resulting in the accelerated breakdown of collagen and elastin in the skin,4,5 as well as contributing to the development of cancer.6 It is estimated that about one-third of solar energy is comprised of IRA, which is capable of deep skin penetration.2
It’s common knowledge that the most effective protection against UV radiation is sun avoidance (for example, limiting exposure, or at least direct exposure during peak times, and by wearing protective clothing). However, total sun avoidance is difficult to achieve for those of us who enjoy spending time outdoors.
In order to achieve as near complete broad-spectrum protection as is possible, a combination of using the right sunscreen and avoiding direct sun exposure when possible is recommended.
An effective sunscreen must provide more than UV coverage, it should protect against IRA as well. When choosing a sunscreen, read the label carefully to make sure your product protects against against UVB, UVA, and IRA. Make sure your sunscreen contains active ingredients such as benzophenone, oxybenzone, avobenzone, titanium dioxide and zinc oxide. These are all ingredients that act as UV filters which are helpful in preventing sun damage.
In addition, antioxidants have also been shown to protect against IRA. Antioxidants that are typically used in sunscreens are comprised of vitamins, (such as Vitamin C and E) and Polyphenols (ex. flavonoids and procyanidins) are present in numerous foods and have been demonstrated to provide protective properties through direct application to the skin.7,8
When spending time outdoors it’s vital to take preventive measures to protect your skin. Reducing your time in the sun is perhaps the easiest way to avoid damage to the skin caused by UV rays. When outdoors, set a time limit and seek shade when necessary. Also keep in mind that UV radiation is the strongest between the hours of 10 a.m. to 4 p.m. Covering up is another effective way to reduce sun exposure. Wrap-around sunglasses, wide-brimmed hats and clothing that covers your arms and legs provides extra protection.
Following these simple steps can help you safely enjoy your time in the sun for many years to come.
For more information, read the full article at Skintherapy Letter:http://www.skintherapyletter.com/2010/15.4/2.html
1.Krutmann J, Gilchrest BA. Photoaging of skin. In: Gilchrest BA, Krutmann J (eds). Skin aging. New York: Springer, p33-44 (2006).
2. Kochevar IE, Taylor CR, Krutmann J. Fundamentals of cutaneous photobiology and photoimmunology. In: Wolff K, Goldsmith LA, Katz S, et al. (eds). Fitzpatrick’s dermatology in general medicine, 7th ed. New York: McGraw-Hill, p797-808 (2008).
3. Calles C, Schneider M, Macaluso F, et al. Infrared A radiation influences the skin fibroblast transcriptome: mechanisms and consequences. J Invest Dermatol (In press 2010).
4. Schroeder P, Pohl C, Calles C, et al. Cellular response to infrared radiation involves retrograde mitochondrial signaling. Free Radic Biol Med 43(1):128-35 (2007 Jul 1).
5. Schroeder P, Lademann J, Darvin ME, et al. Infrared radiationinduced matrix metalloproteinase in human skin: implications for protection. J Invest Dermatol 128(10):2491-7 (2008 Oct).
6. Jantschitsch C, Majewski S, Maeda A, et al. Infrared radiation confers resistance to UV-induced apoptosis via reduction of DNA damage and upregulation of antiapoptotic proteins. J Invest Dermatol 129(5):1271-9 (2009 May).
7. Allemann IB, Baumann L. Botanicals in skin care products. Int J Dermatol 48(9):923-34 (2009 Sep).
8. Krutmann J, Yarosh D. Modern photoprotection of human skin. In: Gilchrest BA, Krutmann J (eds). Skin aging. New York: Springer, p103-12 (2006).