Re: OT: Vitamin D levels chart

The synthesis of vitamin D starts in the bowel epithelial with the oxidation of cholesterol from food or bile to pro-vitamin D3 (7-dehydrocholesterol). This is then transported to the skin, where it is isomerized to pre-vitamin D3 (cholecalciferol) by UVB radiation.

So the main precursor for the conversion of Vitamin D is 7-dehydrocholesterol.
Certain drugs such as cortisone and statins interfere with the production of this pro-vitamin and therefore the production and conversion of Vitamin D is restricted in this way, resulting in a deficiency.

Chrisb1.