Vitamin D is a fat-soluble vitamin that can be found from few dietary sources such as cod liver oil, eggs, fish and fortified milk. The sun is also a major source of this vitamin which is synthesized by the skin when exposed to ultraviolet rays. Vitamin D supplement is thus an essential substitute in provision of vital nutrients that are found in the above named sources.

These supplements help in absorption of calcium in the gut and in maintaining adequate levels of serum calcium and phosphate concentration thus building of stronger bones and teeth.

The supplements are also useful in prevention of rickets and osteomalacia which usually lead to skeletal deformation and muscular weakness. They also help in prevention of breast, prostrate, cervical cancer and other forms of cancers. Other conditions that can be prevented by taking vitamin D supplement include autism, hypertension, multiple sclerosis, skin pigmentation disorders, diabetes (type 1 and 2), chronic pain, neuromuscular diseases, autoimmune disease, depression, chronic pain, hyperparathyroidism, and flu.

The recommended daily intake of Vitamin D supplement is 200 IU per day for infants while children and adolescents should take 400 UI per day. Adults should consume an average of 1000 UI each day.