Of all minerals, this is the most abundant minerals found in the skeletal and bone tissue. Approximately 1200 gm of calcium is found in our body, of which 99% is combined as salts-mainly as calcium phosphate which gives hardness to the bones and enable them to hold the weight of a body.
Function of calcium
- It activates several enzymes such as pancreatic lipase, adenosine triphosphates and some proteolytic enzymes.
- It catalyzes the clotting of blood.
- Calcium is necessary for synthesis of acetylcholine, a substance that is necessary for transmitting nerve impulses.
- It helps to absorb vitamin B12 in the ileum.
- Calcium vital function is to regulate contraction and relaxation of muscles, including the beating of heart.
- It helps the absorption process by increasing the permeability of cell membranes.
- Adequate amount of calcium is needed for the growth of children.
Deficiency of calcium
Calcium deficiency are usually accompanied by lack of phosphorus and vitamin D. vitamin D deficiency alone can produce calcium deficiency syndromes. A severe deficiency of calcium leads to rickets in children and osteomalacia in adults. Pure calcium deficiency is osteoporosis, in osteoporosis serum calcium level is normal but body store is reduced. There are some deficiency are:
- Osteomalacia or adult rickets
Sources of calcium
- Milk and milk product ( milk, yogurt, cheese, ice-cream) are the best sources of calcium
- Ragi (nachi) is the cheapest sources of calcium it is known as poor men’s milk
- Sesam seeds
- Green leafy vegetables (amaranth, drumstick leaves, mustard green, spinach, fenugreek (methi) etc)
- Tapioca are good source of calcium
- Small fish (mandeli), fish oil
Recommended dietary allowances
FHO/WHO export group (1984) has recommended:
- 400-500 mg calcium/ day for adult men and women
- During pregnancy and lactation the requirement increases to 1000 mg calcium/ day
- For infants 500-600 mg calcium/day
- For children of between 1-9 years 400-500 mg calcium/ day
- For age group 10-15 years 600-700 mg calcium/day