Heather Bedard, C.H.E.
The sun…one of the most necessary and demonized parts of our existence. If you listen to any sunscreen marketing campaign, you may find that you’re at imminent risk of skin cancer by exposing yourself to the sun for any length of time. However, while protection from the sun by avoidance and constant sunscreen application has increased dramatically, the incidence of melanoma skin cancer is on the rise as well. Perhaps what we’ve been told about the sun is only a part of the story.
The sun interacts with your body via ultraviolet radiation which then interacts with your skin and different systems in your body. Your skin converts
7-dehydrocholesterol into vitamin D which is then translated into other forms of vitamin D which is necessary for the immune system, bones, and blood cells. Vitamin D also helps your body to absorb nutrients such as calcium and phosphorus.
Vitamin D isn’t the only benefit you get from the sun, however. Sunlight also increases nitric oxide production lowering blood pressure.[1] This is one of the reasons you feel better getting outside during the day. On the other hand, sunlight also helps with hormone production such as serotonin.[2] It is important, if you can, to get out in the sun for 10-15 minutes early in the morning. You will begin to produce more serotonin over the course of the day and then when evening comes, your body will convert serotonin to melatonin. The higher your production of serotonin, the happier you are and the better your sleep! In this way the sun affects your sleep/wake cycles.[3],[4]
Last, but not least, our amazing sun also stimulates neuroendocrine production (which has to do with your hormones) and immune system functions.[5] The fact is, that sunlight is crucial to your body functioning properly. A lack of sun exposure is a risk for all-cause mortality (death by any cause) of a similar degree as smoking![6]
While there are cautions in regard to the sun and damage to your skin, the truth is somewhere in the middle. Your body NEEDS the sun and popping a vitamin D pill is not an adequate substitute.
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[1] Liu D, Fernandez BQ, Hamilton A et al. “UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase.” J Invest Dermatol 2014 Jul;134(7):1839-1846 [2] Lambert GW, Reid C, Kaye DM, Jennings GL, Esler MD. “Effect of sunlight and season on serotonin turnover in the brain.” Lancet 2002 Dec 7;360(9348):1840-2. [3] Van der Rhee HJ, de Vries E, Coebergh JW. “Regular sun exposure benefits health.” Med Hypothesis 2016 Dec;97:34-37 [4] van der Rhee H, Coebergh JW, de Vries E. “Is prevention of cancer by sun exposure more than just the effect of vitamin D? A systematic review of epidemiological studies.” Eur J Cancer. 2013 Apr;49(6):1422-36. [5] Slominsky A. “Neuroendocrine activity of the melanocyte.” Exp Dermatol 2009 Sept;19(9):760-763 [6] Lindqvist P, Epstein E, Nielsen K, Landin-Olsson M, Ingvar C, Olsson H. “Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort.”J Intern Med. 2016 Oct;280(4):375-87
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