Vitamin D (calciferol) is a fat-soluble vitamin that is produced primarily by the skin in the presence of sunlight (UVB rays). In this respect vitamin D differs from all other vitamins, which can be supplied primarily through the diet. It is particularly advisable to increase your dietary intake of vitamin D in the darker winter months, when the body has a limited ability to produce sufficient quantities of this vitamin.

The vitamin D contributes to
- the maintenance of normal bones and teeth
- normal absorption and utilisation of calcium
- normal cell division
- normal function of the immune system
- the maintenance of normal muscle function

The following groups of people may have higher vitamin D requirements:
Children and adolescents, pregnant and breastfeeding women and elderly people.

Sources: Liver, fatty fish, such as herring or salmon, and eggs.