21st Century High Potency Vitamin D3-1000IU Tablets For Bone & Immune Health are formulated with Vitamin D3 (Cholecalciferol), the body’s preferred form of Vitamin D, commonly known as Sunshine Vitamin. Vitamin D is normally obtained from the diet or produced by the skin from the ultraviolet energy of the sun. However, it is not abundant in food. As more people avoid sun exposure, vitamin D supplementation becomes even more necessary to ensure that your body receives an adequate supply. As we age, our bodies may absorb this important nutrient less efficiently. Vitamin D deficiency has been linked to mood disorders, chronic diseases and autoimmune diseases over the years. Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and to prevent hypocalcemic tetany. It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts. Without sufficient Vitamin D, bones can become thin, brittle, or misshapen. Vitamin D is essential in regulating the absorption of calcium and phosphorus, and facilitating normal immune system function. Getting a sufficient amount of vitamin D is important for normal growth and development of bones and teeth, as well as improved resistance against certain diseases. 21st Century High Potency Vitamin D3 formulation supports the maintenance of bones and teeth, supports the health of the immune system, brain, and nervous system.