What is vitamin D?
Hormone precursor (prohormone) would actually be the more appropriate name for vitamin D. The body converts it into a hormone called calcitriol. It is the biologically active form of vitamin D.
What is vitamin D3?
Vitamin D2, also called ergocalciferol, also belongs to the vitamin D group. It is converted in the body into the more effective form vitamin D3.
You can find out more about cholecalciferol here.
Vitamin D production with the help of the sun
In winter, however, solar radiation in our latitudes is too weak for sufficient vitamin D production in the skin. The body then falls back on the vitamin D3 stored in the form of calcifediol, if available. The stores are primarily located in muscle and fatty tissue.
What are the functions of vitamin D in the body?
The main vitamin D function in the body is in the area of the bones:
Further, but partly not yet clearly scientifically proven effects of vitamin D:
- Strengthening of the immune system, both in the defense against pathogens and in the inhibition of excessive immune reactions (helpful in autoimmune diseases such as type 1 diabetes and multiple sclerosis)
- Strengthening of the musculature
- protective effect for the nerve cells in the brain
- positive effect on the cardiovascular system
- reduction of vascular diseases
- protective effect against cancer
- positive effect on the psyche
What is the daily requirement of vitamin D?
Experts estimate the vitamin D requirement from one year of age at 20 micrograms (µg) of vitamin D daily. Infants need about half that.
The German Nutrition Society (DGE) has developed (DACH) reference values that are considered adequate and well tolerated. This is how high the vitamin D intake should be if the body’s own synthesis is lacking.
|
Age |
Vitamin D intake in the absence of endogenous synthesis (in µg/day) |
|
10 |
|
|
1 to 14 years |
20 |
|
15 to 64 years |
20 |
|
from 65 years |
20 |
|
Pregnant |
20 |
|
Breastfeeding |
20 |
To prevent rickets, infants (i.e. children up to the end of the 1st year of life) are regularly given a vitamin D supplement. This ensures that the vitamin D requirement is actually covered – regardless of whether the child is breastfed or not and how much the body produces itself. In the 2nd year of life, children should still receive the vitamin D supplement during the winter months.
People who live vegan are particularly susceptible to an undersupply if they do not spend enough time in the sun. Vitamin D is only found in significant amounts in very few plant foods, such as some edible mushrooms and vitamin D-enriched margarine.
Keyword solarium
Experts therefore advise against going to the solarium to prevent vitamin D deficiency!
Vitamin D: Foods with high content
Even if our food contributes little to the supply of vitamin D, one should pay attention to a sufficient supply in the diet. You can find out which foods have notable vitamin D values in the article Foods with high vitamin D content.
How does a vitamin D deficiency manifest itself?
How does a vitamin D overdose manifest itself?
Just like a deficiency, an excess of vitamin D can have serious consequences. However, practically no surplus can occur through sun exposure or diet. The situation is different with vitamin D supplements. You can read more about the side effects of high doses of vitamin D in the article Vitamin D: Overdose.