Vitamin D, also known as calciferol, is technically not a vitamin, but really a fat-soluble prohormone (hormone precursor with little hormonal activity itself). The two major forms of vitamin D are D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D3 is photosynthesized in the skin when it is exposed to ultraviolet radiation (UVB radiation), and vitamin D2 is made naturally in plants when they are exposed to ultraviolet radiation. The main function of Vitamin D was previously believed to be in the prevention of diseases such as, rickets and osteomalacia. However, there has been recent discoveries that vitamin D may also help prevent a variety of diseases such as: cancer, cardiovascular disease, multiple sclerosis, rheumatoid arthritis, congestive heart failure, stroke, type 1 diabetes, chronic pain, high blood pressure, and may help defend the body against microbial invasion.
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