Calcium Benefits and Information
Calcium is an essential mineral with a wide range of biological roles and is arguably one of the most important minerals you should take in order to maintain good health. While the majority of calcium is located in the bones and the teeth it is also required for blood coagulation, nerve function, production of energy, the beating of the heart, proper immune function and muscle contraction. But most of us recognize calcium for the possible role it plays in preventing the onset of osteoporosis.
The amount of calcium in your blood is regulated by PTH (parathyroid hormone). Some researchers believe when the human body does not receive enough calcium levels of PTH increase whereby causing the body to experience hypertension. High levels of calcium in the body have been associated with a lower risk of cardiovascular disease in postmenopausal women, lower cholesterol levels and a decrease in the symptoms of premenstrual syndrome (PMS). Low levels of calcium have been associated with reduced bone mass and osteoporosis. One preliminary study also suggests that calcium may help reduce the risk of obesity.
Additional research suggests that calcium may help to reduce the risk of colon cancer, a killer of older men. In double-blind studies, calcium supplementation has shown to be helpful in protecting against precancerous changes in the colon. A few epidemiological studies have also noted an inverse relationship between colon cancer incidence and calcium intake. However not all studies substantiated these findings.Which Form of Calcium Should I Take?
One of the largest factors to consider when choosing which calcium is best is the percentage of elemental calcium present. A greater percentage of elemental calcium means that fewer tablets are needed to achieve the desired calcium intake. For instance, in the calcium carbonate form, calcium accounts for 40 of the compound, while the calcium citrate form provides 24 elemental calcium.
For people concerned about cost and only willing to swallow a few calcium pills per day, calcium carbonate is a great choice. Even for these people, however, low-quality calcium carbonate supplements are less than ideal. Depending on how the tablet is manufactured, some calcium carbonate pills have been found to disintegrate and dissolve improperly, which could interfere with absorption.
Calcium carbonate may not always show optimal absorption, but it clearly has positive effects. For example, calcium carbonate appears to be absorbed as well as the calcium found in milk. In fact, some studies indicate that calcium carbonate is absorbed as well as most other forms besides calcium citrate/malate (CCM).
For people willing to take more pills to achieve a given amount of calcium, typically 800-1,000 mg, calcium carbonate does not appear to be the optimal choice because other forms, such as calcium citrate, have been reported to be more absorbable. For this reason, some doctors recommend other forms of calcium, particularly CCM (Calcium Citrate Malate). However, CCM is not the only form of calcium that might be absorbed better than carbonate.
Microcrystalline hydroxyapatite (MCHC) has attracted attention of many medical practitioners and supplement users because of studies reporting increases in bone mass in people with certain conditions and better effects on bone than calcium carbonate. However, unlike CCM, MCHC has only in very few instances been compared with other forms of calcium.
Recently, coral calcium has been claimed to be a vastly superior form of calcium even though its calcium content is primarily calcium carbonate. One small, controlled human study reported that coral calcium was better absorbed than ordinary calcium carbonate. There is however little scientific evidence at this time supporting the assertion that coral calcium is superior to other forms of calcium.
Whatever form of calcium supplementation you select, calcium typically is absorbed better when eaten with food. Research also indicates that taken with meals calcium may reduce the risk of kidney stones, while supplementing with calcium between meals might actually increase the risk.Suggested Dosage
The National Academy of Sciences has established guidelines for calcium that are 25-50 higher than previous recommendations. For ages 20 to 50, calcium consumption is recommended to be 1,000 mg daily; for adults over age 51, the recommendation is 1,200 mg daily. The most common supplemental amount for adults is 800 to 1,000 mg per day.Precautions
Calcium supplements should be avoided by prostate cancer patients.Supporting LiteratureBell L, Halstenson CE, Halstenson CJ, et al. Cholesterol-lowering effects of calcium carbonate in patients with mild to moderate hypercholesterolemia. Arch Intern Med. 1992; 152:2441-2444.
Baron JA, Beach M, Mandel JS, et al. Calcium supplements for the prevention of colorectal adenomas. N Engl J Med 1999;340:101-107.
Baron JA, Tosteson TD, Wargovich MJ, et al. Calcium supplementation and rectal mucosal proliferation: a randomized controlled trial. J Natl Cancer Inst 1995;87:1303-1307.
Bostick RM, Kushi LH, Wu Y, et al. Relation of calcium, vitamin D, and dairy food intake to ischemic heart disease mortality among postmenopausal women. Am J Epidemiol 1999;149:151-160.
Garland CF, Garland FC, Gorham ED. Calcium and vitamin D. Their potential roles in colon and breast cancer prevention. Ann NY Acad Sci. 1999; 889:107-119.
Heaney RP. Calcium, dairy products and osteoporosis. J Am Coll Nutr. 2000; 19(2 Suppl):83S-99S.
Jorde R, Sundsfjord J, Haug E, et al. Relation between low calcium intake, parathyroid hormone, and blood pressure. Hypertension 2000;35:1154-1159.
Lipkin M, Newmark H. Effect of added dietary calcium on colonic epithelial-cell proliferation in subjects at high risk for familial colonic cancer. N Engl J Med. 1985; 313:1381-1384.