Vitamin D also known as calciferol is a collective name for several sterol derivatives build with similar construction.
From a nutritional perspective Vitamin D2, D3 and the pro-vitamins they are created from are especially interesting. D2 has a vegetable origin, and D3 has an origin from animals.
Thanks to the construction of Vitamin D when it comes to the placement of carbon atoms in the structure it enables absorption of UV-radiation which can form new Vitamin D.
Vitamin D ingested from food is absorbed in the small intestine and is transported by the lymph into the blood for further transport into the liver in which the vitamin is stored.
The vitamin that is created from radiation of the sun, also called cholecalciferol (D3) is transported together with a blood-protein into the liver for storage. The primary translation begins in the liver and is basically the same for vitamin D2 and D3. The majority are normally from cholecalciferol (D3).
Vitamin D affect around thirty tissues in the body, and the effective substances are transported through the liver, into the kidneys for further transport into the specific areas around the body.
A couple of organs Vitamin D affect are; intestinal and bones in which the vitamin maintain important functions.
Vitamin D was first isolated in the 1930s and afterwards the research was stalled for a couple of decades. At the end of the 1960s new technology enabled intensification of the researches and in the year 1971 it was confirmed that Vitamin D actually was more than a vitamin alone, it was a so-called pro-hormone. Since then, intense research have been taking place and is the reason why we have such great preparations to treat for instance certain bone diseases.
Vitamin D participates in the absorption of both calcium and phosphate. Vitamin D is part of the mineralization of bones and teeth, and the available amounts of calcium and phosphate are important for this process.
Rickets which is a skeleton disease due to deficiency of Vitamin D was first described in detail during the 1600s by D. Whistler and F. Glisson.
The reason of deficiency may be answered by; reduced availability due to lack in the diet, poor absorption or abnormal conversion to the active metabolites.
During deficiency there is a lack of deposition of calcium and phosphate in bones, and also in the teeth. There is also a risk that serious disorders of the calcium-balance may lead to complications in soft-tissues as well with convulsions as a result for instance.