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Calcium
Description:
Calcium is the most abundant mineral in the human body. Your body contains 2 to 3 pounds of calcium. For proper calcium absorption, vitamin D, fluoride and silicon are needed. Calcium works closely with phosphorus and magnesium.
Method of Action:
Calcium phosphate constitutes the bulk of inorganic matrix of bone. It is deposited within the soft, fibrous organic matrix as hydroxyapatite, adding to the bone's structural rigidity.
Calcium is also one of the major mineral constituents of tooth enamel and dentin, both of which serve as rigid exterior protection for the sensitive interior pulp of the tooth. The vast majority of calcium absorption takes place via active transport in the duodenum and is greatly facilitated by the action of vitamin D, lactose, and high levels of dietary protein.
Vitamin D deficient diets, diets high in fat, and High Fiber Diets have the reputed effect of curtailing calcium absorption, which is only 10 to 30% efficient under usual physiological conditions.
When serum blood levels of calcium fall, parathyroid hormone is secreted. This stimulates increased absorption of calcium from the intestine and resorption of calcium from the bone. However, high blood calcium levels trigger the release of the hormone calcitonin, which induces renal excretion of calcium and inhibits further resorption from the bone. The mutuality of these two hormones allows a feedback control of calcium levels in blood serum.
Consumption of dairy products, one of the primary food sources of calcium, can decrease absorption of most tetracycline antibiotics, with the notable exceptions of deoxycycline and minocycline.
Neomycin, cycloserine, erythromycin, sulfonamides, tetracyclines, penicillin, isoniazid, and para-aminosalicylic acid reportedly decrease calcium absorption to some degree.
Properties & Uses:
Calcium has been used in the management of uremic bone disease, a disorder in which chronic renal failure produces abnormally high serum phosphate levels and, reciprocally, low serum calcium levels.
It is thought that unexplained calcium deficiencies may be related to excessive magnesium depletion. Calcium supplementation helps to prevent the excessive resorption of calcium from the bones. Experimentation has shown that adequate calcium intake can prevent and, on occasion, reverse resorption of bone in human periodontal disease.
Calcium and vitamin D supplements are effective in the treatment of osteomalacia; vitamin D promotes increased calcium absorption within the duodenum.
Although not a proven cure, increased calcium and vitamin D intake is beneficial for the elderly with osteoporosis, as it counteracts the high rate of calcium efflux characteristic of this disease. In conjunction with vitamin D, calcium is effective in alleviating symptoms of vitamin D-dependent rickets.
Toxicity Levels:
Although excessive calcium intake has not been shown to be toxic, an extremely high intake of calcium in conjunction with a high intake of vitamin D can induce hypercalcemia. This condition can result in excessive calcification of bone and soft tissue (e.g., the kidney), or in the formation of kidney stones.
Recommended Dietary Allowances:
1000-1200 mg
Older adults, and pregnant/nursing women should aim for the higher end of this spectrum. If taking supplements, calcium citrate is the recommended form.
Food Sources:
Almonds, Brazil nuts, blackstrap molasses, broccoli, calcium fortified cereal & juice, caviar, cheese, cottage cheese, green leafy vegetables, kelp, milk products, canned salmon & sardines, tofu, turnip greens, yogurt.
Deficiency Symptoms:
Muscle cramps, tingling in the arms and legs, cramps, joint pain, heart palpitations, dental cavities, insomnia and stunted growth are some symptoms of calcium deficiency. Brittle bones, a humped spine and osteoporosis may result over time. Children with extreme calcium deficiency may develop rickets, a disease that causes deformed bones. Too much magnesium or phosphorus in the diet may lead to a calcium deficiency, as can excessive smoking, alcohol or consumption of soft drinks.