Study after study continues to confirm that vitamin D plays an important role in many areas of health. Still, many people find it difficult to get adequate levels of the nutrient. In fact, the Centers for Disease Control and Prevention estimates that one-third of all U.S. adults have insufficient levels. This underscores the need for people to find ways to get more vitamin D.

Some foods naturally have vitamin D. Oily fish, mushrooms and fortified products contain a certain amount of the nutrient. However, naturally occurring vitamin D is relatively scarce in foods. The other primary way to get the nutrient is through sun exposure. But this poses another problem, as spending too much time in the sun may be linked to skin cancer.

For these reasons, many experts recommend that individuals consider supplementation.

"There's no way you can get enough vitamin D without taking a supplement or without going out in the sun at the right time of day," John Cannell, a doctor in San Luis Obispo, California, told the Muncie Star Press. "The truth is the sun causes cancer, that's true."