What is vitamin D?

Vitamin D is a fat-soluble vitamin and is primarily responsible for regulating calcium and phosphate metabolism for healthy bones, cartilage and teeth. Vitamin D is also involved in modeling the immune system and plays a major role in our mental state.

Vitamin D is produced in the body with the help of sunlight in the skin and is also absorbed through foods such as fatty fish, eggs, mushrooms or avocado. 80% of the requirement is covered by the body's own production, absorption through food plays a subordinate role.

Both endogenously produced vitamin D and vitamin D from food are activated in the liver to form 25-hydroxyvitamin D3 (calcidiol). Due to its stability, this form of vitamin D is a good marker for vitamin D levels. The next activation step takes place in the kidneys to form 1,25-dihydroxyvitamin D3 (calcitriol). This is the biologically active form of vitamin D, which finally binds to special vitamin D receptors and exerts an effect in the cells.

Many steps in vitamin D metabolism can be significantly influenced by various gene variants, such as the function and activation of vitamin D receptors, activation enzymes or transport proteins.

A vitamin D deficiency manifests itself in bone malformations, exhaustion, susceptibility to infections, frequent respiratory diseases, muscle weakness and depressive moods.

Examples of foods rich in vitamin D:

What does genetics have to do with it?