[[Cholecalciferol]], also known as [[vitamin D]]3, is a type of vitamin D that is naturally produced in the skin when it is exposed to sunlight. It can also be obtained from dietary sources such as fatty fish, egg yolks, and fortified foods. 
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Cholecalciferol is important for bone health as it helps the body absorb calcium and phosphorus from food. It also plays a role in immune function and has been linked to a reduced risk of certain types of cancer, cardiovascular disease, and autoimmune disorders. In some cases, cholecalciferol supplements may be prescribed by healthcare professionals to treat vitamin D deficiency or certain medical conditions.