Health professionals are united in their opinion that most people, especially women, are not consuming the Recommended Daily Allowance of calcium. Various health experts, including a National Institutes of Health panel, have even recommended consumption above the recently revised Recommended Daily Intake levels to optimize bone health and increase other potential health benefits. With the growing medical consensus that Americans need to increase their intake of calcium through supplementals, the question arises: how much is too much?
The answer: calcium is extremely safe. It is very hard to consume too much calcium. Most of the calcium absorbed by the body, and not used by bone, is excreted in the urine. The Handbook of Nonprescription Drugs notes that daily consumption of as much as 8 grams of elemental calcium, causes few side effects in healthy people.
Calcium has been tested extensively in women with osteoporosis, women at risk for osteoporosis, and pregnant and nursing women. These studies, using varying amounts of supplemental calcium, typically between 1,000 and 2,500 mg per day, provide meaningful evidence of what constitutes a safe daily amount of calcium. Calcium supplementation is the main risk reducer of osteoporosis. Studies of calcium related to fractures in post-menopausal osteoporotic women and the process of bone formation and loss in osteoporosis have found doses of 1.5 to 2.5 grams per day of elemental calcium to be safe.
Calcium supplementation is also increasingly being considered in the maintenance of healthy blood pressure in pregnant women. Increased calcium intake is already a standard recommendation for women who are pregnant or lactating to support the additional calcium needs of mother and baby. Supplemental calcium between 1,000 and 2,000 mg per day was found to be safe in pregnant women in a recent study. In one trial over 4,000 women were given 2 grams (2,000 mg) per day of elemental calcium. No significant adverse events or high calcium in the blood were reported.
How much calcium is enough and how much is too much? Supplemental calcium up to 2,000 mg per day appears to be safe and effective in helping to prevent osteoporosis and may reduce the risk for pregnancy-induced high blood pressure. At present there is little evidence that higher doses provide any further health benefit in most healthy individuals, although selected individuals may require up to 2,500 mg.
Calcium, like all minerals and vitamins, if consumed in great excess, can potentially produce adverse effects. A single incidence, or several days of excessive consumption, is unlikely to cause any harm. However, such patients should be monitored for signs of abuse. Studies have examined patients with excess calcium in the blood and milk-alkali syndrome, a potentially dangerous and rare complication. Antacid abuse in the range of 4 grams (4,000 mg) to 60 grams (60,000 mg) of elemental calcium daily for a prolonged period of time, usually combined with milk and for months or years, has been reported in patients with milk-alkali syndrome.
The 1994 NIH Consensus Development Conference on Optimal Calcium Intake examined most of the published literature on dietary calcium and supplementation, and heard from experts on the effects of calcium on osteoporosis, heart disease, pregnancy and cancer. In their final report the panel stated that most current evidence points to doses up to 1,500 mg per day as being helpful in preventing and treating osteoporosis. The panels report concluded that 2 grams, or 2,000 mg, of elemental calcium per day consumed regularly was safe for most people. Another report from the National Academy of Sciences Institute of Medicine evaluating the RDAs for various nutrients sets a "Tolerable Upper Intake Level" for calcium at 2,500 mg per day, which is an amount unlikely to pose risks of adverse health effects in most healthy individuals.
If people are interested in more information about appropriate individual dosages, they should consult their physician.
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These are the proper calcium dosages.