Vitamin D is a fat-soluble vitamin. On one hand it gets into our system with the food we are eating and on the other hand, our bodies are able to produce vitamin D by themselves. For that cholesterol is transported into the skin and when sunlight hits our skin the production of vitamin D starts.
The fact that our body is capable of producing this vitamin on its own makes it technically a hormone.
The vitamin D production is very much dependent on the angle of incidence of the sun rays. According to this, the synthesis is only possible from April to September.
Functionality
- regulates the entire calcium balance
- vitamin D is the hormone that helps the gut to absorb more calcium
- a lack of vitamin D can cause bone diseases for example osteoporosis
- improvement of muscle strength
- crucial for thyroid hormones
- a positive influence of coronary blood vessels
A lot of people suffer from a vitamin D deficiency
The high numbers of deficiency are based on the fact, that the sun rays for more than 6 months of a year are not suitable for the vitamin D synthesis on our skin. And it doesn´t help that a lot of people are inside their houses or offices for the most part of the day. So there is big lack of sunshine!
People over 65 have a weaker vitamin D synthesis, it´s age-related and can´t be fixed with a higher
amount of sun rays or more hours outside.
When you are using sunscreen it prevents sunburns by blocking UVB light. That means it also lowers vitamin D levels. Check this article I found …
People with darker skin tend to require more sun exposure. Melanin is the substance in the skin that makes it dark and lowers the vitamin D production. Regulating the intake of vitamin D with your nutrition gets more important.
Low levels of this nutrient occur when our body doesn´t absorb the necessary levels. The results can be misshapen or thin bones and also:
- tiredness,
- concentration difficulties
- might cause depression
- circulatory disturbance
It often shows that an increase of depression is mostly around wintertime when the days 
are shorter and the sun is shining less.
Vitamin D rich foods
- cod liver oil
- tuna, sardines, salmon
- avocado
- eggs
- mushrooms
The amount of vitamin D we are getting with our nutrition is not enough to cover all the needs.
For example … you have to eat 1 kg herring to cover your daily requirement.
