Vitamin D is one of the fat-soluble vitamins and assumes in its active form different functions in the body. It is very important especially for the bones and plays a role in calcium and phosphate homeostasis. In addition, support of the body when the immune system and ensures that form progenitor cells of bone cells and mature.

The largest part is formed by the body itself. UV-radiation is incident on the skin and converted to Vitamin D. In addition, we take the nutrient in the food, and most foods do not have a large vitamin D content. The vitamin is in oily fish such as contain herring and salmon, fish oil, egg yolk and dairy products in unusually high amounts.