Advantages of calcium -

#Calcium ion is essential for a large variety of important physiological functions, including muscle contraction, nerve stimulation, hormonal release, cell membrane, permeability, proper enzyme function.

#Calcium is necessary to stabilize the activity of a number of proteins and enzymes. The binding of calcium ions is required for the activation of "vitamin K-dependent" clotting aspects in the blood coagulation process.

#Calcium, especially calcium derived from dairy products help adjust body fat.

#Calcium helps slow bone loss in postmenopausal women, may reduce premenstrual syndrome symptoms, and is associated with reduced threat of colorectal cancer.

#The body requires calcium to make strong teeth and healthy bones. The bones serve as the storage place for the body's calcium. They continuously release calcium into the bloodstream, and then keep replacing it as the body's requirement for calcium arises. When calcium intake is low, there is poor absorption; and there is a high probability of bone breakdown because the body uses up the stored calcium to perform normal biological functions.

#Calcium is also needed for muscle contraction and maintenance of cell membranes.

#Calcium supplements help alleviate mood swings, food cravings, pain, and bloating associated with premenstrual syndrome.

What is the recommended daily requirement of calcium?

Optimal calcium intake depends according to a person's age, sex, and ethnicity.

The U.S. Recommended Dietary Allowance for calcium is 1,000 milligrams per day - given for adults (except pregnant or lactating women) and children over 4 years of age.

It is about 1200 milligrams for individuals older than 50 years of age.

The calcium intake of vegans tends to be slightly below the recommended optimal amounts but the body does adapt to lower intakes. Since vegetarians have a slightly lower protein intake and rule out meat from their diet, encourages their bodies to retain calcium so their dietary need is relatively lower.

Sources of Calcium -

Dairy products (milk, yoghurt, cottage cheese, cheese) are the main sources of calcium. Individuals with lactose intolerance (people who cannot completely digest the milk sugar lactose) and those who are vegans tend to avoid or eliminate dairy products from their diet. We all know that it is important for vegetarians to meet calcium needs with alternative calcium sources.

Good vegan sources of calcium include tofu (if prepared from calcium sulphate), green leafy vegetables, dried figs, broccoli, seeds and nuts. Some soya milks, instant breakfast cereals are also fortified with calcium. Drinking water can provide as much as 200mg of calcium daily, as hard water contains a rich source of calcium.

Although most grains are not high in calcium, they do contribute calcium to the diet because they are consumed regularly and frequently.

What affects calcium absorption and excretion from the body?

Only 20-30% of calcium in the average diet is absorbed into the body, the rest gets excreted.

A high protein diet, especially based on animal foods, causes calcium loss in the body. The higher sulphur-to-calcium ratio of meat increases calcium excretion.

Calcium absorption can also be affected by the amount of calcium present in the body, amount of vitamin D presence (helps improve calcium absorption), age, pregnancy (intestinal calcium absorption increases during pregnancy), fibre content in diet etc. The amount of calcium consumed at one time such as in a meal is inversely related to the absorption rate.

Calcium excretion refers to the amount of calcium eliminated from the body through urine, feces and sweat. Calcium excretion is affected by factors such as amount of sodium, protein, caffeine and potassium in diet.

Calcium is lost in cooking some foods even under the best conditions.

To retain calcium:

*Foods are best cooked in a minimal amount of water.

*Cook food for the shortest possible time.

What does calcium deficiency lead to?

Osteoporosis: major cause of bone fractures in the elderly, especially women. Prevention includes an adequate intake of calcium throughout life, but especially in childhood and young adulthood; and reducing trigger factors such as smoking, heavy drinking and lack of physical exercise.

Diets high in protein and salt also increase calcium loss from the body. Post-menopausal women are more prone because they produce less oestrogen, which protects the skeleton in younger women.

Rickets is a childhood disorder involving softening and weakening of the bones. It is caused by lack of vitamin D, calcium, or phosphate. Deficiency of vitamin D leads to improper regulation of calcium and phosphate. Symptoms of rickets in children include delayed sitting, crawling, walking and the development of bowlegs