Question: My doctor told me that I should take 3,000 units of vitamin D a day and, as a result, I don't need to be exposed to the sun. What is your opinion on this?
Answer: Although many people rely on vitamin D supplements, believing that it is an adequate replacement for sun exposure and useful as a nutrient or hormone to treat and prevent chronic illnesses, including cardiovascular disease, type 2 diabetes, osteoporosis, autoimmune diseases, and cancers, it is becoming more apparent that we benefit in many other ways when exposed to the broad spectrum of solar radiation. Vitamin D production from the skin when exposed to sunlight is just one of the many photochemicals produced in the skin that have important implications for overall health. Sun exposure is able to reduce blood pressure, whereas vitamin D supplementation alone is not. Exposure to sunlight leads to the production and release of nitric oxide and beta-endorphin; increased production in adrenocorticotropin hormone; and enhancement of collagen synthesis and wound healing. These processes are controlled by various energies (i.e., wavelengths within the solar spectrum including UVA, UVB, and visible and infrared radiation).
In addition, solar exposure has a direct influence on the immune system, inducing immune tolerance and improving the body's ability to fight infection by dangerous germs. Source: The D-lemma: narrow-band UV type B radiation versus vitamin D supplementation versus sunlight for cardiovascular and immune health. American Journal of Clinical Nutrition, 2017.
My advice: Try to get at least 15 minutes of sun exposure a day, even if you are taking vitamin D pills.