Calcium is absorbed in the small intestine; this process is dependent on vitamin D. To provide the rigid structure of the skeleton calcium is vital, around about 3lb of the body's weight is calcium, 99 per cent being in the teeth and bones. It is important in growing children to help bones grow and the elderly as the ability to absorb calcium becomes impaired with age. Together with magnesium it is needed for nerves and muscles to function properly. It also helps to maintain the right acid/alkaline balance and blood to clot. An adult needs a daily calcium intake of between 700 and 1000mg. Those at risk of osteoporosis may need as much as 1500mg a day. This protection is boosted when combined with linoleic acid from evening primrose oil. Calcium and phosphorus work together on a ratio of two to one for healthy teeth and bones and calcium and magnesium work together for cardiovascular health. The two most deficient minerals in a women's diet are calcium and iron.

Calcium supplements have shown to protect against pre-eclampsia which is high blood pressure in pregnancy. It is a good idea to increase calcium consumption during the last three months of pregnancy and the first few months of lactation to ensure that the baby get sufficient amount of calcium to help bone development and growth. If the baby doesn't get enough calcium from its mother, it will be withdrawn from the mothers bones, possibly leading to bone disease in the future.

Signs of calcium deficiency are rickets, osteomalacia and osteoporosis.

Calcium like sodium and potassium contribute to both extracellular and intracellular cell environment. Calcium is also needed as intercellular cement to keep the cells of the body together. It also controls fluid to allow enzyme reaction to take place. Calcium is vital for the contraction of muscle. The brain sends nerve impulses that release calcium in the muscle which triggers muscle reactions. Calcium also helps to control cholesterol.

Calcium helps in the process of secretion, bile, pancreatic fluid, gastric, intestinal, hormonal and mucous all rely on calcium to move the small droplets through the cells boundaries and cell walls.

The AMP (adenosine monophosphate) is calcium dependent. This maintains the balance of proteins in the body.

Calcium is also needed in the release of neurotransmitter. These are vital for a proper functioning nervous system.

Calcium is one of the ?buffers? in blood that helps to keep the levels of acid/alkaline. Calcium levels in the blood are affected by hormones. If levels drop then Tetany could occur; this is a condition that causes tremors and involuntary contractions of the muscles.

Osteoporosis, which means ?porous bones?, is at epidemic proportions particularly in women after the menopause. It is a painful and potentially crippling disease which is due to the loss of calcium in the bones. By the age of fifty up to 25 per cent of the skeleton could be missing due to Osteoporosis, this can increase the risk of bone fractures, loss of height and formation of a 'dowager's hump? all due to the soft and thinning bones. This will affect one in three women and one in twelve men by the age of seventy.

The conventional explanation of why Osteoporosis affects women of a certain age more than men is that once a women stops menstruating she produces only a small amount of the oestrogen which helps to keep calcium in her bones. This is why women are recommended to take hormone replacement therapy (HRT). This is not the case as research has shown that Progesterone stimulate osteoblasts to produce new bone and that by taking Progesterone it increases bone density by four times, oestrogen which stimulates osteoclast cells only stops the loss of old bone.

A women stops ovulating in the time before and after the menopause. Even though the body still produces a little amount of oestrogen if no ovum is released then no progesterone is produced. Scientists now believe that it is the deficiency of progesterone not oestrogen that is precipitating osteoporosis.

This is not the only factor in the cause of osteoporosis; diet is also a strong factor which is why it is uncommon in some cultural groups. The lack of calcium in the diet is thought not to have a huge baring on osteoporosis, in fact the Bantu tribes of Africa have on average a calcium intake of 400mg and their women suffer little osteoporosis whereas the Eskimos have a substantial higher intake of calcium in their diet but their women suffer from high incidents of osteoporosis. The problem seems to be too much dietary protein.?

The Eskimos have more protein in their diet than the Bantu tribes. Protein-rich foods are acid-forming. The body cannot tolerate acid level changes and it uses the alkaline agents - sodium and calcium to neutralise the acid effect. When all the sodium reserves are used up by the body it takes calcium from the bones. This is why a high protein acid forming diet leads to calcium deficiency and may also be the primary cause of osteoporosis. This may well explain why vegetarian women suffer less from osteoporosis. In fact vegetarians in general need less calcium than those who eat meat because of the reduce intake of protein.

Omega 3 and 6 fatty acids which are found in fish oil and evening primrose oil if taken in large doses increase the absorption of calcium from the gut like vitamin D does. Not only do they increase calcium absorption but they also reduce calcium loss in the urine. PUFAs prevent the abnormal deposition of calcium in soft tissue and increase calcium levels in bones. PUFAs can help with the bone loss at menopause.

In summary, calcium is a very important mineral in the diet especially with women at menopausal age. It can stop the onset of osteoporosis and reduce bone loss and fragility. It is also important for pregnant women, growing children and the elderly.