Provitamins
Ergocalciferol and Cholecalciferol
transport and storage ad 25- OH Cholecalciferol
Active form- Calcitriol
Functions
on three target tissues
Intestinal cell- increases absorption of calcium
Bone- Mineralization of bones
Kidney- increases tubular absorption of calcium
increases serum calcium level
Deficiency manifestation
Rickets in children
Osteomalacia in adult
RDA- 400 IU in children, 200 IU in Adult
Sources- Sunlight, fish, egg yolk etc.
