Vitamin D has long been known as the sunshine vitamin because skin creates this hormone when exposed to ultraviolet light. However, winter in northern latitudes does not allow much vitamin D to be created. Research indicates that adequate vitamin D may improve the outcomes of assisted reproduction (American Journal of Obstetrics and Gynecology, JUne 2019). Some evidence suggests that vitamin D supplements may also help reduce migraine frequency (Current Pain and Headache Reports, Feb. 21, 2019). On the other hand, the VITAL trial showed that vitamin D did not reduce cardiovascular disease or cancer. Consequently, many people wonder about the most appropriate dose and the best source for vitamin D.
Let Your Arms and Legs See Some Sun:
Q. I used to be an x-ray technologist. We were taught that the lower arms and hands as well as lower legs and feet could safely take more radiation than the rest of the body. With that in mind, I take short mid-morning walks with my forearms and lower legs exposed to sunlight without sunscreen.
Perhaps that is why my vitamin D levels are normal without supplementation. Scientists should explore what parts of the body might safely take more sunlight and at what dose, so as to avoid skin cancer.
A. Many dermatologists believe that there is no amount of sun exposure that is good for the skin. That’s understandable since they are dealing with an epidemic of skin cancer.
On the other hand, vitamin D supplements have not lived up to expectations. Scientists don’t understand why high-dose vitamin D injections have not prevented falls or fractures (Lancet, Diabetes & Endocrinology, June 2017). In addition, high-dose vitamin D supplementation did not prevent respiratory infections (Clinical Infectious Diseases, July 11, 2020).
Your idea of limited sun exposure, especially in the morning, is not unreasonable. Natural vitamin D production may have health benefits that neither pills nor shots can provide. Of course, you would need to take care to avoid sunburn. To learn more about the importance of vitamin D and how to determine if you are getting enough, you may want to consult our eGuide to Vitamin D and Optimal Health.
Is Sunshine Really the Best Source for Vitamin D?
Q. When you think about supplementing vitamin D, your first choice should be sunshine, the most natural source. Vitamin D by itself doesn’t work; calcium, magnesium, phosphorus and iron are also necessary, along with vitamins A and K.
A. We love sunshine as a source of vitamin D, but there are circumstances when sun exposure isn’t practical. During the winter in most of the northern states, it is too cold and there isn’t enough sun to get vitamin D from sunshine on the skin. Even in the summertime, some people take medications that make them susceptible to sunburn. People with skin cancer must use sunscreens. They block vitamin D formation. There is still room for vitamin D supplements.
Other Supplements That Affect Vitamin D:
We think it does make sense to check your intake of magnesium as well as vitamin D. Additionally, some scientists propose that vitamin K2 is also important in the metabolism of vitamin D (Schwalfenberg, Journal of Nutrition and Metabolism, June 18, 2017). While we need vitamin D to absorb calcium well, we need vitamin K to get calcium into bones and keep it out of artery walls (Karpinski et al, Journal of the American College of Nutrition, July 2017).
Over the course of the whole year, sunshine is an excellent source for vitamin D. Even certain individuals taking supplements of vitamin D3 have higher levels of 25-hydroxyvitamin D, the circulating form of this hormone, when they go out in the sun (O’Sullivan et al, Photochemistry and Photobiology, Jan. 16, 2019). We discuss dosing, signs of low vitamin D and home tests for vitamin D levels in our Guide to Vitamin D Deficiency.
