Calcium is the most important and largely required mineral in the Dietary Sources body. Think of bones as a calcium bank, which we keep constantly withdrawing from. If we keep depositing calcium regularly in them, it will come to our aid in old age. The body of an infant has 28 gm at birth, and an adult has 1100 gm of calcium in the body, and its 99% is in bone and teeth to provide strength and rigidity. The remainder is in the blood, muscles, and nerves to help in physiological functions.

The amount in the blood is usually about 10 mg per 100 ml. There is a dynamic equilibrium between the calcium in the blood and that in the skeleton; this equilibrium is maintained by the parathyroid glands and cholecalciferol (vitamin D). Calcium is a white, malleable, metallic element and is found in the body as calcium carbonate, its compounds like calcium sulphate, calcium fluoride, and calcium phosphate. Its absorption gets retarded with lot of fat, oxalic acid, and phytic acid in the diet. This mineral is absorbed from the intestinal tract into bloodstream, which gets enhanced with vitamin D, C, B-12 and phosphorus.

Functions on the Body: The calcium is essential for strong teeth and healthy bones. Of all the tissues in the body the bone tissue is the one which bears the burnt of malnourishment and lack of exercise. Your health depends on adequate nourishment with attention to calcium-rich foods along with weight bearing exercise like walking. When the supply of calcium is restricted bones give up their own supply to the body, setting the stage for osteoporosis (thinning of the bones). Porus bones (brittle like chalk) cannot withstand the weight of exercises. So they crumble or collapse leading to fractures, mostly in wrist, hip and spinal column being major sites of bone loss, even in ordinary activities like bending, lifting etc.

Dietary Sources: Diary products like milk, curd, yoghurt, cheese and its other by-products are the best sources of available and usable calcium. Switch to soya milk if you are lactose (enzyme present in dairy products) intolerant with uncomfortable digestive effects. Also rich in calcium is spinach, fenugreek leaves, patra leaves, mustard leaves, dry figs, almonds, whole meal bread/flour, potatoes, dried apricot, citrus, celery, parsley, certain fish like pomfret, and fruits like guavas. Too many of dairy products can constipate you. To prevent it include other calcium rich item like bran cereals, breads, ragi, sea same seeds, pulses, rajmah, soyabean, poppy seed, dry, coconut, vegetables and fruits, and drink enough water (at least eight glasses a day). Weight conscious people can have skim milk and low fat dairy products to get enough nutrition and low-fat benefits too. High fibre meals may bind calcium. So a calcium supplement is best taken half-an-hour after meals.

Recommended Daily Allowance: The RDA is 400 to 500 mg of calcium for children and adults. For menopausal women, who do not take estrogen, it will be 1000 to 15000 mg of calcium. Unfortunately, calcium tablets by themselves are barely absorbed and the calcium is excreted in the urine unutilized. So take the calcium supplement along with the vitamin D, which is available in oily fish, fortified cereals, or exposure to sunlight. The excess of calcium can cause kidney damage, constipation, nausea, excessive thirst, abdominal pain and general confusion.