Why Do People Become Vitamin-D Deficient?

There are actually two forms of vitamin D: vitamin D3 and vitamin D2. Vitamin D3 is also called cholecalciferol. It is formed in the skin upon exposure to the sun. Vitamin D2 (ergocalciferol) comes from food and some types of nutritional supplements. Once vitamins D3 and D2 have been formed, they are transported in the blood to the liver where chemical transformation occurs to create a molecule called 25-Hydroxyvitamin-D. This chemical is important as it is the primary form of circulating vitamin D and is one that is most frequently measured in vitamin D Testing, which I’ll teach you...