Calcium is the most abundant mineral in the body. About 99 percent of the calcium in the body is deposited in the bones and teeth. One percent is involved in the blood-clotting process, in nerve and muscle stimulation, parathyroid hormone function, and metabolism of vitamin D.
The ratio of calcium to phosphorus in the bones is 2.5 to 1. To function properly, calcium must be accompanied by magnesium, phosphorus, and vitamins A, C, D, and very possibly vitamin E.
The major function of calcium is to act in cooperation with phosphorus to build and maintain bones and teeth. It is essential for healthy blood, eases insomnia, and helps regulate the heartbeat. An important calcium partner in cardiovascular health is magnesium.
In addition, calcium assists in the process of blood clotting and helps prevent the accumulation of too much acid or too much alkali in the blood. It also plays a part in muscle growth, muscle contraction, and nerve transmission. Calcium aids in the body's utilization of iron, helps activate several enzymes (catalysts important for metabolism), and helps regulate the passage of nutrients in and out of the cell walls. Calcium is present in significant amounts in a very limited number of foods. Milk and dairy products are dependable sources. Those who are unable to use bone meal may use calcium gluconate or calcium lactate, natural derivatives of calcium which are even easier to absorb than is bone meal.
Calcium absorption is very inefficient, and usually only i to 30 percent of ingested calcium is absorbed. About 100 to 200 milligrams are filtered through the and excreted in the urine.Another 125 to 180 milligrams are excreted in the feces.Some is lost in sweat. Absorption takes place in the duodenum and in the lower part of the intestinal tract when food content becomes alkaline. Many other factors influence the actual amount of calcium absorbed. When in need, the body absorbs calcium more effectively; therefore the greater the need and the smaller the dietary supply, the more efficient absorption. Absorption is also increased during nods of rapid growth.
Calcium needs acid for proper assimilation. If acid some form is not present in the body, calcium is not dissolved and therefore cannot be used as needed the body. Instead it can build up in tissues or joints as calcium deposits, leading to a variety of disturbaces.
Calcium absorption also depends upon the presence of adequate amounts of vitamin D, which works with parathyroid hormone to regulate the amount of calcium in the blood. In hyperparathyroidism, too much calcium is taken from the bones. Phosphorus is needed in at least the same amountas calcium.The body uses calcium and phosphorus together to give firmness to bones. If excessive amounts of either mineral is taken, as in the typical American diet of too little calcium and too much phosphorus, that excess cannot be used efficiently.Vitamins A and C are necessary for calcium absorption. Fat content in moderate amounts, moving slowly through the digestive tract, helps facilitate absorption. Certain substances interfere with the absorption of calcium. When excessive amounts of fat combine with calcium, an insoluble compound is formed which cannot be absorbed. Oxalic acid, found in chocolate, spinach, and rhubarb, when combined with calcium makes another insoluble compound and may form into stones in the kidney or gallbladder. Large amounts of phytic acid, present in cereals and grains, may inhibit the absorption of calcium by the body. Other interfering factors include lack of exercise, excessive stress, excitement, depression, and too rapid a flow of food through the intestinal tract.
The National Research Council recommends 800 milligrams as a daily calcium intake; since only 20 to 30 percent is absorbed, 800 milligrams would maintain the necessary balance. During pregnancy and lactation, this amount increases to 1200 milligrams. With age, it seems the requirement also increases because the rate of absorption is reduced. If the calcium intake is high, the magnesium levels also need to be high. Too little magnesium results in calcium accumulation in muscles, heart, and in the kidney, causing kidney stones.
A high intake of calcium and vitamin D is a potential source of hypercalcemia. This condition may result in excessive calcification of the bones and some tissues, such as the kidney's. Too much calcium can interfere with the functioning of the nervous and muscular systems. When an excess of calcium is added to blood plasma, coagulation does not take place. Animal studies show that too much calcium can decrease the body's absorption of zinc.
Deficiency Effects and Symptoms
One of the first signs of a calcium deficiency is a nervous affliction, tetany, characterized by muscle cramps and numbness and tingling in the arms and legs. A calcium deficiency can result in bone malformation, causing rickets in children and osteomalacia in adults. Another calcium deficiency ailment is osteoporosis, in which the bones become porous and fragile because calcium is withdrawn from the bones and other body areas faster than it is deposited in them.
Moderate cases of calcium deficiency may lead to cramps, joint pains, heart palpitation, slow pulse rates, tooth decay, insomnia, impaired growth, and excessive irritability of nerves and muscles. In extreme cases of deficiency, brittle or porous bone and tooth formation, slow blood clotting, or hemorrhaging may result.
Confinement, most commonly experienced in bed rest following an illness, depletes calcium from the bones and nitrogen from muscle tissue. To prevent this condition from becoming serious, gradual exercise should be undertaken as soon as possible.
Beneficial Effect on Ailments Calcium has been successfully used in the treatment of osteoporosis. The hormones involved are stimulated by the concentration of calcium ions in the blood. Calcium is a natural tranquilizer and tends to calm the nerves.
Calcium has been beneficial in the treatment of cardiovascular disorders. In addition, calcium is a recognized aid for cramps in the feet or legs. It also helps patients suffering from "growing pains."
Calcium has been used in the treatment and prevention of sunburn. In addition to giving protection against effects of sun damage such as redness and subsequent peeling, it also protects against sun-caused skin cancers. Calcium helps the skin to remain healthy. Vitamin A and calcium are a good combination for protection of the skin. This combination can also be used as a neutralizing agent against the poison of a black widow spider or a bee sting.
Arthritis, structural rigidity often caused by depletion of bone calcium, can be helped with regular supplements of calcium. Early consumption of calcium may help prevent arthritis. Rheumatism can also be treated successfully with calcium therapy.
Problems of menopause, such as nervousness, irritability, insomnia, and headaches, have been overcome with administration of calcium, magnesium, and vitamin D. When there is not enough calcium in the body to be absorbed, the output of estrogen decreases. Calcium can help prevent premenstrual tension and menstrual cramps.
High intakes of calcium may relieve the symptoms commonly associated with aging. Some of the disorders include bone pain, backaches, insomnia, brittle teeth with cavities, and tremors of the fingers.
The parathyroid glands located in the neck help adjust the body's storage of calcium. If these glands are not functioning properly, calcium accumulation may occur. The remedy for this situation is to renew the proper function of the parathyroid glands rather than to cut down on calcium intake.
Calcium treatments have been used successfully in treating rickets in children and osteomalacia in adults. In addition, nephritis has been cleared up with administration of calcium and other nutrients. Tooth and gum disorders are also relieved by higher intakes of calcium in the diet. A high dietary intake of calcium may protect against the harmful effects of radioactive strontium 90.