Nutrition Health Review

Summer 2017

Nutrition Health Review provides consumers updates on the latest medical research, news, trends, and products in nutrition and healthy living.

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I t was during the mid 1980s when the Skin Cancer Foundation first started its public awareness campaign on skin cancer prevention, including the dangers of too much sun exposure. 1 Let's see...that's right around the time I was using baby oil in lieu of sunscreen while sunbathing because I heard it would increase the sun's potency for creating that "perfect" tan. What can I say? I was a teenager who thought Flock of Seagulls, big hair, and insanely high waistbands were super cool, and I definitely wasn't paying attention to anything the Skin Cancer Foundation had to say (ignorance is bliss). Besides, the future was far, far away, and the notion that I was prematurely aging my skin and increasing my risk for skin cancer was well hidden behind the enigmatic mists of future adulthood. These days, teenagers, along with the rest of us, are better informed on the importance of protecting our skin from sun exposure, and the importance of protection isn't limited to just those individuals with light or fair skin. According to the American Academy of Dermatology (AAD), "Anyone can get skin cancer, regardless of age, sex or race. In fact, it is estimated that one in five Americans will develop skin cancer in their lifetime." 2 Exposure to UV radiation from the sunlight can lead to skin cancer (melanoma and non- melanoma), and the AAD recommends seeking shade, wearing protective clothing, and applying a broad- spectrum sunscreen with a sun protection factor (SPF) of 30 or higher if you want a healthy lifestyle and healthy skin. 2 But is exposing our skin to sunlight a complete no-no? Let's take a look at some research that supports the benefits of moderate exposure. Your body uses sunlight to produce vitamin d. There are two main ways to get vitamin D: through exposure to UVB sunlight and through ingestion, whether through diet or supplements. There has been a steady flow of research supporting the notion that moderate sun exposure has many health benefits. 3 For example, you can get about 80 percent of your required vitamin D through exposure to UVB sunlight. 3 But you have to be sensible! Experts say that sensible sun exposure would be 5 to 10 minutes of exposure of the arms and legs or the hands, arms, and face two or three times per week. 4 But other researchers disagree. For example, the AAD expressly does not recommend getting vitamin D from sun exposure (natural) or indoor tanning (artificial), and says the risk of developing skin cancer from the UV exposure outweighs the benefits. 2 steady, consistent, exposure to the sun puts you at less risk for developing malignant melanoma than inconsistent or intermittent exposure. Science gets a little tricky here. It appears that people who maintain a year-round tan have a lower risk of developing malignant melanoma. In other words, intermittent "recreational" sun exposure (e.g., exposure limited to weekend outings or vacations) is usually associated with greater melanoma risk than chronic sun exposure. 5 Chronic or "occupational" sun exposure— the kind outdoor workers, for example, get on a consistent basis—is associated with lower rates of malignant melanoma. 6,7 More studies are needed to determine exactly why this is. It's important to note, however, that chronic sun exposure is still strongly associated with other types of skin cancer. Vitamin d increases the skin's resistance to the sun. Research has shown that taking vitamin D supplements increases sun tolerance and protection against sun damage. Various forms of the vitamin D prohormone reduced sunburn and lowered incidence of tumor development in a mouse model. 8 So... getting sun gives you vitamin D, which in turn protects you from too much sun (try not to overthink that one). sun exposure at noon is less dangerous than later in the day. This is when UVB and vitamin D production are highest. The popular advice "that sun exposure should be avoided for three to five hours around noon and postponed to the afternoon" is Summer 2017 • Volume 116 7 J un;48(6):866–874. 1 4. Eberlein-König B, Ring J. Relevance of vitamins C and E in cutaneous photoprotection. J 1 5. Burke KE, Zhou X, Wang Y, et al. The effects of t opical L-selenomethionine on protection against UVB-induced skin cancer when given before, during, and after UVB exposure. J Drugs Dermatol. 2 014;13(10):1214–1223. 1 6. Clark LC1, Combs GF Jr, Turnbull BW, et al. Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin: a randomized c ontrolled trial. Nutritional Prevention of Cancer S tudy Group. JAMA. 1996;276(24):1957–1963 17. Ramsden CE, Zamora D, Leelarthaepin B, al. Use of d ietary linoleic acid for secondary prevention of c oronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. BMJ. 2013;346:e8707. 1 8. Essential fatty acids and skin health. Oregon State U niversity site. http://lpi.oregonstate.edu/mic/health- disease/skin-health/essential-fatty-acids#lipid- m etabolism. Accessed August 1, 2017. 1 9. Borkow G. Using copper to improve the well-being of the skin. Curr Chem Biol. 2014;8(2):89–102. 2 0. Ogawa Y, KawamuraT, Shimada Sl. Zinc and skin b iology. Arch Biochem Biophys. 2016;611:113–119. 21. Rostami MM, Safavi NA, Maleki N, Soflaee M. C orrelation between the severity and type of acne l esions with serum zinc levels in patients with acne v ulgaris. Biomed Res Int. 2014;2014:474108. N HR Is Moderate sun exposure healthy? continued on next page * by elizabeth A. Klumpp

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