Food and Health

Source: (Elliot, Edward, Eason, NRC, Robbins, Dierauf en Guland, Klasing, Crissy, mcGill)
Vitamin D3 (also known as cholecalciferol) is a vitamin that dissolves in fat. Using ultraviolet light (UV), the skin makes vitamin D3 from cholesterol.
When there is enough UV radiation, it is less important to have vitamin D3 present in the diet. However, the contribution of this vitamin from UV radiation may vary according to the species. On top of that, the amount of UV radiation in sunlight depends on where the animal lives.
Due to the uncertain contribution of vitamin D3 from sunlight it is advisable to supplement the feed with vitamin D3. Vitamin D3 occurs naturally in animal products. A good source of D3 is fatty fish. Another form of vitamin D is vitamin D2. Vitamin D2 comes from plants.

It is a well known phenomenon that reptiles that live in terrariums have a shortage of vitamin D3. However, a surplus of the vitamin has also got negative results. Extreme high dosages can lead to acute poisoning. It is used, for example, as mice poison. Another result of excess vitamin D3 is hypercalcemia, which may cause disfigurement of the skeleton.
The interaction with other nutrients may influence the working of vitamin D3. A high intake of calcium and phosphor increases the risk of a vitamin D3 surplus. A high intake of vitamin A, on the other hand, checks the working of vitamin D3.