Vitamin D Foods
Distribution :- Fish-liver oils are the richest sources. Butter, milk and eggs moderate quantities.
Function and mode of action.
1. Favours calcium absorption from the intestine.
2. It promotes the absorption of phosphate if there is increased absorption of calcium.
3. Vitamin D maintains normal structure of bone and assists to govern the equilibrium between bone calcium and blood calcium. Calciferol in small amounts increase the excretion of calcium by kidneys and in large doses excretion of phosphate also.
4. Helps in the development of the normal teeth. In deficiency of vitamin D the formation of the teeth becomes defective and leads to the development of dental caries.
Daily requirement :->
Exogenous vitamin D is required throughout the period of skeletal growth, i.e. to adult life. The recommendations for infants under 1 year are 400-800 i.u. daily, and for children and adolescents up to 20 years-400 i.u.. This should be simultaneously supplemented wirh adequate in take of calcium and phosphorus. In the latter half of pregnancy and throughout lactating period, the dose should be 400-800 i.u. .
VITAMIN D (CALCIFEROL)
Properties :- D2 is a white, crystalline material, soluble in fat and fat-solvent, stable in heat,acids and alkalis,and reistant to odourless, crystalline compound, solvents such as ether , chloroform, and acetone.