Called "the sunshine vitamin," vitamin D is a crucial nutrient that is normally obtained through the diet or produced by the skin after exposure to ultraviolet rays from the sun. Vitamin D promotes the body's absorption of calcium, which is essential for the normal development and maintenance of healthy teeth and bones. It promotes bone mineralization in concert with a number of other vitamins, minerals, and hormones.
Calcium is also important to nerve cells, including the brain. The main function of phosphorus is in the formation of bones and teeth. It plays an important role in the body's utilization of carbohydrates and fats and in the synthesis of protein for the growth, maintenance, and repair of cells and tissues. It is also crucial for the production of ATP, a molecule the body uses to store energy. Animal research suggests that vitamin D may help maintain a healthy immune system, by assisting in the regulation of the normal function and growth of immune cells.
The National Institutes of Health have stated that it is important for individuals with limited sun exposure to include good sources of vitamin D in their diets to prevent deficiency.