It 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 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 likely “wrong and may even promote cutaneous malignant melanoma (CMM).”9 Here’s an explanation from a natural health site for why this may be: “First of all, you need a shorter exposure time [to produce vitamin D] because the UVB is more intense.” (Remember, vitamin D is supposed to protect us from too much sun.) “…when the sun goes down towards the horizon, the UVB is filtered out much more than the UVA. And it turns out that the long wave of ultraviolet called UVA…is highly correlated with melanoma—where the UVB is the one that produces the vitamin D…”10 So UVB is highest at noon, which is used to produce vitamin D, and thus vitamin D production is highest at noon..and vitamin D protects us from the sun. Make sense?
I think it’s fair for us to conclude that moderate, consistent sun exposure might be healthier than strict avoidance or chronic, daily exposure. But before you start singing the Bain de Soleil jingle, consider this: What’s “moderate” for you might be very different than what’s “moderate” for me, because things like skin type and geographical location can impact your skin’s tolerance and the sun’s strength, so use common sense. It also seems prudent to use sunscreen with an SPF of 30 or greater if you are going to be exposed to direct sunlight for longer than 10 minutes.
SOURCES: 1) Skin Cancer Foundation site. History. http://www.skincancer.org/ about-us/history-of-the-foundation. Accessed September 1, 2017; 2) Sunscreen FAQs. American Academy of Dermatology site. https://www.aad.org/media/ stats/ prevention- and-care/sunscreen-faqs. Accessed September 1, 2017; 3). van der Rhee, et al. Regular sun exposure benefits health. Medical Hypotheses. 2016;97:34–37;) 4) Razzaque, et al. Sunlight exposure: Do health benefits outweigh harm? J Steroid Biochemis Molecul Biol. 16 September 2016 E-pub ahead of print; 5) Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr. 2004;80(6 Suppl):1678S–1688S. 6) Nelemans PJ, et al. Effect of intermittent exposure to sunlight on melanoma risk among indoor workers and sun- sensitive individuals. Environ Health Perspect. 1993;101(3):252–255; 7) Kennedy C, et al. The influence of painful sunburns and lifetime sun exposure on the risk of actinic keratoses, seborrheic warts, melanocytic nevi, atypical nevi, and skin cancer. J Invest Dermatol. 2003;120(6): 1087–1093; 8. Holly EA, et al. Cutaneous melanoma in women. I. Exposure to sunlight, ability to tan, and other risk factors related to ultraviolet light. Am J Epidemiol. 1995;141(10):923–933; 9) Dixon KM, et al. 1α,25(OH)2-vitamin D and a nongenomic vitamin D analogue inhibit ultraviolet radiation-induced skin carcinogenesis. Cancer Prev Res (Phila). 2011;4(9):1485-94; 10) Moan J, et al. At what time should one go out in the sun? Adv Exp Med Biol. 2008;624:86–88. NHR