Sunlight VS Vitamin D Supplements

sunlight, vitamin d, d, d supplement, immune, bone health, health supplement

Despite the fact that most people wrongly associate sun exposure to skin cancer, over the past few years, numerous studies have touted the vast health benefits associated with vitamin D levels. Due to this new awareness, vitamin D supplementation has shot through the roof, and with good reason.  But vitamin D supplementation may not even scratch the surface in terms of health benefits when you compare it with producing natural vitamin D via sun exposure.

The health benefits of sunlight are multifaceted, and the production of vitamin D is just one of the myriad beneficial effects of sun exposure. This article will explain why vitamin D supplementation doesn’t hold a candle when compared to regular sun exposure.

  1. Multiple Health Mechanisms: When your skin is exposed to sunlight, particularly ultraviolet B (UVB) radiation, it not only produces vitamin D but also triggers other physiological and biochemical processes. For instance, sun exposure leads to the release of nitric oxide from the skin, which can help increase oxygen uptake and delivery, as well as lower blood pressure. This same mechanism is not replicated when consuming vitamin D supplements[1].
  2. Full Spectrum Vitamin D: The form of vitamin D produced in our skin in response to sun exposure is a full spectrum vitamin D3 (cholecalciferol). Some supplements, especially older versions, contain vitamin D2 (ergocalciferol), which is less potent and has a shorter duration of action in the body compared to D3[2].
  3. Natural Regulation: Sun exposure regulates the amount of vitamin D produced in the skin, so the body has the exact amount it needs. The body has a feedback mechanism that prevents the overproduction of vitamin D3, reducing the risk of vitamin D toxicity. This self-regulating mechanism isn't present when consuming supplements, potentially leading to over saturation if not properly monitored[3].
  4. Absorption and Conversion: Vitamin D needs to be converted in the liver and kidneys into its active form, calcitriol, in order to be available to the cells. It's believed that the vitamin D produced from sun exposure might be more easily converted and used by the body compared to supplement forms[4].
  5. Other Beneficial Sun Effects: Exposure to sunlight has been linked to improved mood and sleep quality, primarily due to the regulation of the hormone melatonin and the neurotransmitter serotonin. Supplemental vitamin D don't offer these same benefits[5].
  6. Holistic Benefits: Regular, moderate sun exposure has been associated with a lower risk of several conditions, such as multiple sclerosis, many cancers, and cardiovascular diseases. While some of these benefits can be attributed to vitamin D, others might be due to different mechanisms initiated by the sun’s rays[6].
  7. Bioavailability: Numerous factors including a person's digestive health, diet, and overall health profile can influence how well vitamin D supplements are absorbed. In contrast, direct sun exposure bypasses the digestive system, ensuring direct synthesis of vitamin D in the skin[7].

In conclusion, while vitamin D supplements can be beneficial, especially for those with deficiencies or limited sun exposure, they aren't a complete replacement for the broad array of benefits offered by direct sunlight. It's essential to achieve a balance between obtaining adequate sun exposure and protecting the skin from excessive UV radiation.


[1] Holick, M. F. (2007). Vitamin D deficiency. The New England Journal of Medicine, 357(3), 266-281.
[2] Wacker, M., & Holick, M. F. (2013). Sunlight and Vitamin D: A global perspective for health. Dermato-endocrinology, 5(1), 51-108.
[3] MacLaughlin, J., Holick, M. F. (1985). Aging decreases the capacity of human skin to produce vitamin D3. The Journal of Clinical Investigation, 76(4), 1536-1538.
[4] Liu, D., Fernandez, et al. (2014). UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase. The Journal of Investigative Dermatology, 134(7), 1839-1846.
[5] Holick, M. F. (2004). Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. The American Journal of Clinical Nutrition, 80(6), 1678S-1688S.
[6] Lambert, G. W., Reid, C., Kaye, D. M., Jennings, G. L., & Esler, M. D. (2002). Effect of sunlight and season on serotonin turnover in the brain. Lancet, 360(9348), 1840-1842.
[7] Lucas, R. M., Gorman, S., Geldenhuys, S., & Hart, P. H. (2014). Vitamin D and immunity. F1000prime reports, 6.

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