Vitamin D is an essential nutrient that supports a number of critical physiological functions in the body—including supporting thyroid health, improving immunity, and building strong bones. A deficiency in vitamin D can result in a long list of less-than-ideal physical and mental symptoms—such as poor bone health, brain fog, a weakened immune system, and a negative mood.
Although it’s arguably one of the most important vitamins for whole-body health, most people don’t get enough of it. In fact, 29% of U.S. adults2 are deficient in vitamin D and an additional 41% are insufficient, even though we can get the vital nutrient through multiple sources (namely: sunlight, food, and supplements).
Of course, the fact that our bodies can absorb vitamin D through the sun may contribute to why so many people are deficient. Most people do not get enough sunlight throughout the day to reach optimal vitamin D levels, especially those who live in northern climates. Wearing sunscreen also inhibits this process (but you should definitely still wear sunscreen to reduce your risk of developing skin cancer), so even if you get outside every day, you probably aren’t getting enough vitamin D from the sun alone.