Calcium

Calcium is the most abundant metallic mineral in the body. A person weighing 11 stone houses 1200g of calcium!. Approximately 1100g will be in the skeleton and teeth and the rest distributed between the nerves, muscle and blood.

The bones and teeth serve as storage sites for calcium in its insoluble form of calcium phosphate in the bone. There is a constant interchange between calcium phosphate in the bone and ionic calcium (soluble) in the bloodstream.

Up to 400 mg of calcium is lost daily in the faeces and 350 mg in urine. This increases in summertime and after the menopause in women. This means that 0.05% of calcium is lost daily.

During pregnancy, the foetus absorbs 30 mg of calcium daily through the placenta and during lactation, the mothers milk supplies 300 mg daily.

A UK study of over 800 people indicated that 73% of the women tested had an intake below the 800mg RDA.

Calcium is derived only from the diet, but drinking water can be a significant source, especially in hard water areas. It is also present in some mineral waters.

Natural Sources

Dairy foods - milk, cheese, milk by-products (especially dried skimmed milk), pulses (particularly soya beans), whole grain cereals, root vegetables, molasses, nuts, fish (especially canned where bones are soft and edible), tofu and white bread (calcium is added to white flour in the UK by requirement of law)

Its Function In The Body

Calcium is the structural component of the bones and teeth.

Calcium acts as a nerve impulse transmitter. When a nerve impulse arrives at a junction of nerve and muscle, it causes calcium to be liberates as free ions. The ions act on the muscle and cause contraction.
It plays a part in the clotting of blood. Calcium activates proteins that coagulate to form a blood clot.
Calcium helps in the absorption of vitamin B12.

Other items of interest

Diseases Linked with Deficiency

Osteoporosis - the most common bone disease but one of the most difficult to treat. It is caused by a lack of calcium uptake by the bone, giving a "honeycombing" effect, reducing the bone mass and weakening the skeletal structure, so increasing the risk of fracture.

35-40% of women over 65 suffer fractures of forearm, femur and vertebrae because of osteoporosis.

Periodontal Disease - an early warning sign in the gums of osteoporosis.
Hypertension - studies indicate improvement of the condition with supplementation. This is especially important to those avoiding dairy foods because of a low fat/low cholesterol diet.
Tetany - spasm and twitching of the muscles.

Who Requires Supplementation?

Vegans
Those allergic to milk products
Over 55's, especially women
Pregnant and lactating women
Heavy alcohol users
Drug users such as prednisolone. Some diuretics, some laxatives
Sufferers from chronic wasting illnesses
Coeliacs and those suffering from fat malabsorbtion
Slimmers or heart patients on low fat/low cholesterol diets
Those on a poor diet or eating mainly processed and refined foods
Convalescents from surgery, burns or injuries
People under particular stress

Notes of Supplementation

Lactating women should consult a doctor as to dosage. Megadoses should be avoided by both pregnant and lactating women.
Calcium should be stored in a cool, dry area away from direct light.
Calcium should not be taken within 1 hour of eating a meal or taking other medicines.
Calcium is not easily absorbed, so larger doses are needed.
Excess amounts are readily excreted to there is no danger of overdosing excepting as in point 1