Vitamin D, also known as cholecalciferol or the “sunshine vitamin”, is a fat-soluble vitamin produced by the body when skin is exposed to sunlight. Its two forms are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).

Vitamin D3 is produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis. It can also be found in some foods and is available as a food supplement. 

Vitamin D promotes calcium and phosphorus absorption, components important for building and keeping strong bones and muscles. It also boosts memory, helps prevent depression, enhances immune system strength, maintains teeth health and has a potential role in preventing cardiovascular disease.

The human body synthesizes vitamin D when exposed to sunlight. Limited exposure to sunlight and age may prevent getting enough vitamin.

Vitamin D deficiency is often characterized by a failure of bone tissue to properly mineralize, resulting in soft bones and skeletal deformities. In children, vitamin D deficiency causes rickets and in adults it can lead to osteomalacia, resulting in weak bones. Vitamin D3 deficiency can also cause chronic fatigue, nervous system disorders (neuropathic pain), infertility, diabetes, diseases of the cardiovascular system. Vitamin D deficiency can also occur with age, if the kidneys cannot convert vitamin D to its active form, increasing the risk of osteoporosis or osteomalacia (demineralization of the bone matrix).