Vitamin D3

Vitamin D is a fat-soluble compound found in cod liver oil and vitamin D-fortified foods. Traces of vitamin D are also found in egg yolks and butter. However, the majority of vitamin D in the body is produced during a chemical reaction that starts with sunlight exposure to the skin.

The main role of vitamin D is to maintain normal calcium levels, which it accomplishes by increasing its absorption from food and reducing urinary calcium loss. Both of these actions help the body retain calcium, supporting healthy calcium balance and helping preserve the calcium stored in bones. When necessary, vitamin D transfers calcium from bones into the bloodstream, which does not benefit bones. Although the overall effect of vitamin D on bones is complex, some vitamin D is necessary for healthy bones and teeth.

Vitamin D plays a role in immunity and blood cell formation and also helps cells “differentiate”, a process that may reduce the risk of cell degeneration. From animal and human studies, researchers have hypothesized that vitamin D may protect people from several autoimmune conditions.

Vitamin D is also important for maintaining healthy insulin levels. Vitamin D receptors have been found in the pancreas, where insulin is produced, and preliminary evidence suggests that supplementation may increase insulin secretion in some people, helping with blood sugar control.