Vitamin D3 occurs in nature almost exclusively in animal sources and particularly in fish, dairy products, eggs and meat. Plants, such as lichens and various fungi contain only very small amounts of the much less effective vitamin D2.
Vitamin D plays a very important role. It is one of the few vitamins that is not absorbed directly from food, but rather produced by skin cells from sunlight. It is not a vitamin in the traditional sense of the word, but rather a pro-hormone.
In contrast to many other vitamins, vitamin D is converted into an important hormone which regulates cell functioning and bodily processes. Almost all bodily cells have special receptors for the vitamin D hormone that are dependent on sufficient supply.
Vitamin D is still being intensively researched. New mechanisms of action of this fascinating vitamin are discovered almost every year. So far, the following statements on vitamin D have been released by the EU (EFSA):
Vitamin D contributes to
- Normal absorption and utilisation of calcium and phosphorus
- Normal blood calcium levels
- The maintenance of bones
- The maintenance of normal muscle function
- The maintenance of healthy teeth
- Normal function of the immune system
Vitamin D has a function in cell division.