For years I have advised patients that judicious exposure to sunlight has multiple health advantages. A recent scientific consensus article in the Journal of the American College of Nutrition addressed this issue as it reviewed the pertinent literature and documents on how UV exposure has many additional health benefits above and beyond those related to improving Vitamin D levels. An excellent precis of this article by Carole Baggerly, et.al. discusses the additional benefits of sun exposure, which includes observations that:
-when skin is stimulated with UVA radiation, nitric oxide is released, which produces vasodilation and lowering of blood pressure.
-the physiological response of skin exposure to sunlight is the thickening of the outermost layer of the epidermis and the increase of skin pigmentation through production of melanin. This paired response actually protects the skin and deeper tissues from the deeper penetrating and damaging UVA rays while retaining benefits from UVB exposure. Though both UVA and UVB exposure result in increased skin pigmentation, the mechanisms are different, with UVB being responsible for the up-regulation of melanin synthesis and thus the protective effects against UV damage to DNA. The best time for creating this response coincides with the time of maximal UVB availability (10 am–3 pm). See more on this in Dr. Baker’s blog article ‘Get your tan at high noon, not in bed.’
-the human skin produces beta-endorphin in response to UVB exposure; these opioid peptides have the result of “increasing a feeling of well-being, boosting the immune system, relieving pain, promoting relaxation, wound healing, and cellular differentiation.”
-light signals received through the eye regulate production of melatonin and serotonin for circadian rhythm control and also play a role in preventing seasonal affective disorder.
-the JACN article goes on to catalogue the weight of evidence for Vitamin D’s benefits in: Type 1 Diabetes, the incidence and survival rates for multiple types of cancer and the reduction of pregnancy related disorders including gestational diabetes, preterm birth, preterm labor, preeclampsia, hypertensive disorders of pregnancy, infection and optimal breastfeeding outcomes.
This publication authoritatively reviews how the current culture of sun avoidance in the United States carries with it both health risks and quantifiable harm. It also supports the concept that judicious exposure to mid-day sun is a health promoting habit.
For more information on all things relating to Vitamin D, go to http://www.grassrootshealth.net/
