A healthy diet is essential to fight against many illnesses. Calcium is a mineral which is essential in maintaining total body health. Our body needs it every day not only to keep bones and teeth strong enough during our life time but also to make sure proper performance of muscles and nerves. A good accretion of Ca in the bones at initial stages in life is the best avoidance of age related bone loss and fractures. A Cow's milk contains rich amounts of Ca. A litre of Cow's milk provide a full day's supplement of Ca. Ca is classically related with dairy products; milk, yogurt, and cheese. These are rich sources of calcium. The rest of calcium comes from vegetables; grains; legumes; fruit; meat, poultry, and fish; eggs and other miscellaneous foods. Insufficient intake of Ca in the diet was reason for its deficiency. It is significant for vegetarians to include adequate amounts of non-dairy sources of Ca in their daily diet. It is more competent to take Ca in smaller doses several times a day and at night before bedtime, which would promote a sound sleep. During conditions like pregnancy and lactation, there is larger depletion of Ca from the mother. Hence the intake needs should be increased. Growing children also require increased amounts of calcium. The Ca present in the blood, tissues and in the skeleton are in balance to one another. The Ca in the bone can be used to compensate its deficiency in blood and when the deficit is compensated, the Ca is redeposited in the bone. If an individual's diet does not gain Ca, there may not be enough amount of Ca available in the blood to be sent back to the bones. Thus failing to maintain rigid bones and total body health. The serum level of Ca is closely regulated with normal total Ca of 2.2-2.6 mmol/L (9-10.5 mg/dL). The smallest drop in serum Ca below the normal level will trigger an immediate response. The body is ready to transfer calcium from other sources to preserve normal serum Ca levels to prevent hypocalcemia using one of three organ systems. The three organ systems are the intestines, the kidney and the bone. Diet that is high in protein and salt also initiate Ca loss from the body and may result in osteoporosis. Post-menopausal women are more prone to osteoporosis since they make less oestrogen which plays a chief role in protecting the skeleton in younger women. When adequate amount of Ca is not available to be absorbed into the body, the efficiency of estrogen hormone diminishes as observed in postmenopausal women. Older men are also seen often affected with the deficiency of Ca. Low Ca absorption may be the result of moderate vitamin D insufficiency. The classic effect of vitamin D is to enable the intestinal absorption of calcium by intermediating active calcium transport via the intestinal mucosa.Most of the new bone formation is accomplished by the age 30. After this growth period, importance is placed on managing bone density and avoiding its loss. After the age of 50, studies have shown that bone density often diminishes substantially so the goal at this life cycle phase is to maintain bone mineral density and diminish bone loss.Although surplus intake of Ca is almost never due to calcium ingestion from foods, the use of Ca supplements (including the voluntary fortification of a range of foods that are not naturally sources of Ca) has augmented, and excess Ca intake may arise as a result of high intake from Ca supplements. Surplus Ca intake can result in adverse effects. Since Ca plays a key role in the metabolism of almost each cell in the body and relates with a large number of other nutrients, disturbances of Ca metabolism may give rise to a variety of adverse effects. Diseases arise when the body has low or high calcium levels. Disorders in calcium metabolism may give rise to hypocalcemia, (decreased plasma levels of calcium) or hypercalcemia (increased plasma calcium levels). The key is avoidance and prompt diagnosis.