Vitamin D & Sunlight
Normally, exposure to sunlight on your skin promotes your ability to make vitamin D. Few foods (unless fortified) contain vitamin D naturally. One dietary source is wild caught fatty fish such as salmon, mackerel, and herring. However, for the majority of people, sun exposure is often the main source of naturally occurring vitamin D.
Vitamin D is vital for both bone formation and maintaining healthy bone. Low levels of this vitamin have also been associated with an increased risk of common cancers, autoimmune disease, hypertension and infectious diseases (4). Think you are getting enough vitamin D from the sun? Unfortunately, because we live in Washington State this just isn’t possible for a large portion of the year. Washington is above 42 degrees latitude, which means that from November to February the sun’s rays alone are not sufficient for production of adequate vitamin D through the skin. You could stand outside, naked, all day and not get enough vitamin D.
Other factors that reduce your skin’s ability to make vitamin D:
~ Dr. Cheatum