A vitamin D supplement works by providing the body with additional vitamin D to supplement an insufficient amount produced. According to WebMD, this additional vitamin D works to moderate levels of minerals such as calcium and phosphorous, boost the immune system, and prevent cancer and autoimmune diseases.
According to the Vitamin D Council, the human body produces vitamin D when bare skin is exposed to sunlight. Vitamin D deficiency is common in areas with long winters that have limited sunlight and require people to cover more of their skin, limiting the amount of vitamin D their bodies can produce. This deficiency is treated by taking oral or topical vitamin D supplements.
According to WebMD, vitamin D plays a very important role in maintaining health, specifically immune system, bone, and heart health. Vitamin D is used to treat a wide variety of conditions, including rickets (caused by vitamin D deficiency), osteoporosis, bone pain and other bone conditions, such as hyperparathyroidism and osteogenesis imperfecta. In addition to bone-related conditions, vitamin D is also used in the treatment of some heart conditions and skin conditions. A versatile supplement, vitamin D is also used to treat PMS, bronchitis, and even tooth and gum disease.