Vitamin D the sunshine vitamin that is essential

Vitamin D

1. Vitamin D 1918 – Sir Edward Mellanby – fat soluble substance with antirachitic properties. Cod liver oil – folk remedy since the early 19 th century This fat soluble vitamin was then named as Vitamin D UV light – converts sterol to vit D and prevents and cures rickets

2. Discovery Vit D exists in 2 forms Vit D3 – cholecalciferol Vit D 2 – ergocalciferol Precursor of vit D -7.dehydro-cholestrol in animals and ergoesterol in plants were discovered in 1922.

3. Synthesis UV rays of sunlight wavelength of 290-315nm, ,initiate the photo conversion of provitamin D3 , 7 – dehydrocholestrol to previtamin D3 in the skin Heat induced isomerisation converts previtamin D3 to vit D3 over a period of 2-3 days Less vit D is synthesized in dark –skinned people African