Vitamin D is one of the few essential vitamins that we can get in our diet and produce ourselves. The mechanism by which we can produce vitamin D is complex, but I will say that one of the steps in its production involves ultraviolet radiation exposure on the skin. We obtain our ultraviolet light from the sun. Thus getting sunlight helps produce vitamin D naturally in our bodies.
Vitamin D deficiency can result from inadequate vitamin D intake, inadequate absorption of the vitamin D in our GI tract, inadequate sunlight, or some combination of these. Certainly the number of people that are vitamin D deficient is greater in the northern states than the southern states. This is presumed to be because of lack of ultraviolet light exposure in the colder, darker northern states. It is also supported by the fact that vitamin D deficiency is found more frequently in the winter months. Despite this knowledge, the medical field does not have any formal recommendations on how much sun exposure is healthy. This is because too much sun exposure is also associated with higher rates of skin cancer.
This is a good question for you to pose to your primary care physician
. He or she can measure your vitamin D level through a blood test and decide if you need vitamin D supplementation. I hope that answer helped.