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Calcium; (symbol Ca)
A naturally occurring mineral, important to maintain strong bones and teeth.
It was discovered by Sir Humphry Davy in 1808; and since then, has been incorporated into such diverse items as bleach, fertilizer and plastics.
It is the most abundant mineral in the human body, with almost 99 per cent of it found in the bones and teeth - helping to build bone mass and prevent osteoporosis (bone loss). It naturally forms about 1.5% of the human body.
However, the remaining 1 per cent, which is in the blood, is of paramount importance to the body as it normalises nerve and muscle function, regulates heart-beat, enables blood clotting, helps to maintain a proper acid-alkaline balance, induces sleep and promotes skin health.
Unfortunately, absorption of calcium in the body is very inefficient and there are a number of factors needed for its proper absorption, including stomach acid (HCI), vitamins A, C and D, magnesium and protein. In addition, regular exercise will promote calcium deposition in bones, while a sedentary lifestyle depletes it, causing porous bones. Pregnant and menopausal women, especially, are very vulnerable to calcium deficiencies and bone loss unless they take calcium supplements. Older men can also be prone to calcium deficiency and also people with digestive disorders, such as ulcers or Crohn's disease, because of the accompanying reduction in stomach secretions.
The best natural sources of calcium are contained in cheese, milk, dark leafy vegetables, bought white bread (because it has fortified flour), canned fish (if the bones are eaten) and yoghurt. Coffee, alcoholics, soft drinks, diuretics, antacids and excess protein can all deplete calcium levels. See 'Calcium; Deficiency Symptoms'