AboutVitamin D is a fat-soluble essential dietary nutrient that interacts with nearly every cell in the body. It’s produced in the body when skin is exposed to the sun’s ultraviolet rays, hence the name, “Sunshine Vitamin.” Vitamin D helps the body absorb calcium which is necessary for the normal growth and development of bones and teeth. Your body also utilizes vitamin D to fight off bacteria and viruses. Vitamin D deficiency is prevalent in the US, with over 40% of the population having a deficiency. This deficiency is common among all those who live in a geographic location higher than 40° latitude during winter, people with naturally dark skin, vegetarians and vegans, and people with little to no sun exposure.