woman in a field in the sun

Sunshine plays an important role in many of our body’s biological processes, but the modern lifestyle limits sun exposure.

For years we have heard the message to limit our exposure to sunlight, especially during the middle of the day to prevent skin cancer. Sunscreen application has become part of our daily routine, ensuring we slather on SPF 15 no matter what season. But have you ever stopped to wonder if you get enough sunshine?

Benefits of sunshine

Increased Vitamin D

As jobs have moved from outdoors to indoors over the last century, our exposure to sunshine has lessened. Multiple studies have shown vitamin D deficiencies in all age groups worldwide, even where there is sun exposure all year long (1).

Sun exposure is necessary for the body to make vitamin D. The skin absorbs ultraviolet-B rays and forms previtamin D3, which is then converted to Vitamin D3 (2). We can also get Vitamin D through our diet, but in limited amounts. Vitamin D2 is found in sun-exposed mushrooms (3). Vitamin D can also be found in fatty fish like trout, salmon, or tuna (4). Because it is found in so few foods, many foods are fortified with vitamin D, such as milk and breakfast cereal.

Studies have shown that high Vitamin D concentrations have benefits such as decreasing risk of cancers, especially colorectal cancer. Higher Vitamin D concentrations have also been noted to decrease risk for heart disease and high blood pressure. Because Vitamin D is needed to help calcium do its job, it helps to increase bone health. Also, Vitamin D can lower the risk for age related macular degeneration of the eyes (2).

Improves Mental Health

After gloomy days when skies clear and the sun shines, cheering up on a sunny day is easy to do. Many studies have been conducted examining the relationship between sunlight and mental health.

Direct exposure to sunlight has a proven effect of decreasing anxiety in employees (5). It is believed that the stimulating nature of sunlight helps employees stay alert, as well as helping employees to calm down from stressful situations.

For people with depression, sunshine improves mood and cognitive function. In one study, higher levels of sunshine exposure were associated with improved scores on questionnaires (6).

Another study suggests a link between the amount of sunshine exposure in the weeks and months before as a protective effect against suicide (7).

Lowers risks for certain cancers

Exposure to UV-radiation decreases the risk of some cancers. Hodgkin lymphoma (HL), a cancer most commonly found in adolescents and young adults, occurred 20-30% less in patients that spent more time in the sun (8). Researchers think the UV rays may help modulate the immune system and decrease inflammation.

Men were 24-38% less likely to develop the main type of kidney cancer, renal cell carcinoma (RCC), the more sunlight they were exposed to (9). Decreases in risk for breast and colon cancer were also noted with higher sunlight exposure (10).

Enjoy the sun responsibly

The risk of developing skin cancer from sun exposure varies greatly and depends on a number of factors. Age and location can also affect risk.

The research suggests that not all sunshine exposure is a bad thing. Sunning before 10 AM and after 2 PM in short doses seems to be the best way to enjoy the sun’s benefits while decreasing risk (11). Aim for a modest amount of exposure, around twelve to fifteen minutes of midday sunshine (12). Talk to your doctor about your risks.

References:

  1. Palacios C, Gonzalez L. Is vitamin D deficiency a major global public health problem? The Journal of Steroid Biochemistry and Molecular Biology. 2014;144:138-145. doi:10.1016/j.jsbmb.2013.11.003
  2. A Catharine Ross, To C, Al E. Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press; 2011.
  3. Nair R, Maseeh A. Vitamin D: The “sunshine” vitamin. J Pharmacol Pharmacother. 2012;3(2):118-126. doi:10.4103/0976-500X.95506
  4. What Is Vitamin D and What Does It Do?; 2016. Accessed August 31, 2021. https://ods.od.nih.gov/pdf/factsheets/VitaminD-Consumer.pdf
  5. An M, Colarelli SM, O’Brien K, Boyajian ME. Why We Need More Nature at Work: Effects of Natural Elements and Sunlight on Employee Mental Health and Work Attitudes. Branchi I, ed. PLOS ONE. 2016;11(5):e0155614. doi:10.1371/journal.pone.0155614
  6. Kent ST, McClure LA, Crosson WL, Arnett DK, Wadley VG, Sathiakumar N. Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study. Environmental Health. 2009;8(1). doi:10.1186/1476-069x-8-34
  7. Vyssoki B, Kapusta ND, Praschak-Rieder N, Dorffner G, Willeit M. Direct Effect of Sunshine on Suicide. JAMA Psychiatry. 2014;71(11):1231. doi:10.1001/jamapsychiatry.2014.1198
  8. Monnereau A, Glaser SL, Schupp CW, et al. Exposure to UV radiation and risk of Hodgkin lymphoma: a pooled analysis. Blood. 2013;122(20):3492-3499. doi:10.1182/blood-2013-04-497586
  9. Karami S, Boffetta P, Stewart P, et al. Occupational sunlight exposure and risk of renal cell carcinoma. Cancer. 2010;116(8):2001-2010. doi:10.1002/cncr.24939
  10. Freedman DM. Sunlight and mortality from breast, ovarian, colon, prostate, and non-melanoma skin cancer: a composite death certificate based case-control study. Occupational and Environmental Medicine. 2002;59(4):257-262. doi:10.1136/oem.59.4.257
  11. Skin Cancer Awareness. American Academy of Dermatology Association. Accessed September 2, 2021. https://www.aad.org/public/public-health/awareness-campaigns/practice-safe-sun
  12. Mead MN. Benefits of Sunlight: A Bright Spot for Human Health. Environmental Health Perspectives. 2008;116(4). doi:10.1289/ehp.116-a160
  13. Image by Jill Wellington from Pixabay 

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