Vitamin D3 occurs in nature almost exclusively in animal sources and particularly in fish, dairy products, eggs and mear. Plants, such as lichens and various fungi contain only very small amounts of the much less effective vitamin D2.
In contrast to many other vitamins, vitamin D is converted into an important hormone which regulates cell function and numerous bodily processes. Almost all body cells have special receptors for a vitamin D hormone and are dependent on a sufficient supply.
Vitamin D is part of a regulatory system that depends on numerous other nutrients.Vitamin D and vitamin K2 are cofactors in the regulation of calcium metabolism.Together, the two vitamins control the formation and breakdown of bone cells and important transport molecules that ensure the correct utilisation of calcium.
Other cofactors are also involved in vitamin D metabolism, including magnesium, calcium, boron, zinc and vitamin A.
Health Claims (as per EFSA):
- Vitamin D contributes to normal absorption and utilisation of calcium and phosphorus
- Vitamin D contributes to normal blood calcium levels
- Vitamin D, vitamin K, calcium, magnesium and zinc contribute to the maintenance of healthy bones
- Vitamin D, calcium and magnesium contribute to the maintenance of normal muscle function
- Vitamin D, calcium and magnesium contribute to the maintenance of healthy teeth
- Vitamin D, zinc and vitamin A contribute to normal immune system function
- Vitamin D, calcium magnesium and zinc play a role in cell division
- Calcium and vitamin A have a function in cell specialisation
- Calcium contributes to normal growth and bone development in children
- Calcium contributes to the reduction of the decrease in bone density in women after menopause (osteoporosis)
- Zinc contributes to normal vitamin A metabolism
Vitamin K2 exists in different forms, each of which has a different level of efficacy. Vitamin K2 MK7 is today considered by far the most effective form of K2. Since vitamin molecules take different chemical forms (the so-called cis-trans isomers of vitamin K2), there are enormous differences even between different vitamin K2 MK7 active substances. It is believed that only the trans forms can be utilised by the body.