Uses based on scientific evidence
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare professional.
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Grade*
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Antacid
Calcium carbonate is an U.S. Food and Drug Administration (FDA) approved over-the-counter (OTC) drug used to treat gastric hyperacidity (high acid levels in the stomach).
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A
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Bone density
Multiple studies of calcium supplementation have found that high calcium intakes may help reduce the loss of bone density. Studies indicated that bone loss could be prevented in many areas including ankles, hips, and spine.
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A
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High blood phosphorous level
Hyperphosphatemia (high phosphate level in the blood) is associated with increased cardiovascular mortality in adult dialysis patients. Calcium carbonate or acetate may be used effectively as phosphate binders. Use may increase calcium-phosphate products in blood. Treatment of high blood phosphorous levels should only be done under supervision of a qualified healthcare professional.
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A
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Hypocalcemia
Calcium supplementation is used to treat conditions arising from calcium deficiencies such as hypocalcemic (low blood calcium) tetany (muscle spasms), hypocalcemia related to hypoparathyroidism (low levels of the parathyroid hormone), and hypocalcemia due to rapid growth or pregnancy. It is also used for the treatment of hypocalcemia for conditions requiring a prompt increase in plasma calcium levels (e.g., tetany in newborns and tetany due to parathyroid deficiency, vitamin D deficiency, and alkalosis) and for the prevention of hypocalcemia during exchange transfusions. Treatment of hypocalcemia should only be done under supervision of a qualified healthcare professional.
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A
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Hypocalcemic tetany
Tetany is a condition of prolonged and painful spasms of the voluntary muscles, especially the fingers and toes (carpopedal spasm) as well as the facial musculature. Hypocalcemic tetany may be brought about by a calcium deficiency. Intravenous calcium has been used to treat hypocalcemia.
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A
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Osteoporosis
Osteoporosis is a disorder of the skeleton in which bone strength is reduced, resulting in an increased risk of fracture. Although osteoporosis is most commonly diagnosed in white postmenopausal women, women of other racial groups and ages, men, and children may also develop osteoporosis.Calcium is the nutrient consistently found to be the most important for attaining peak bone mass and preventing osteoporosis. Adequate vitamin D intake is required for optimal calcium absorption. Adequate calcium and vitamin D are deemed essential for the prevention of osteoporosis in general, including postmenopausal osteoporosis.Although calcium and vitamin D alone are not suggested as the sole treatment of osteoporosis, they are necessary additions to pharmaceutical treatments. The vast majority of clinical trials investigating the efficacy of pharmaceutical treatments for osteoporosis have investigated these agents in combination with calcium and vitamin D. So, although calcium alone is unlikely to have an effect on the rate of bone loss following menopause, osteoporosis may not be treated in the absence of calcium. Treatment of postmenopausal osteoporosis should only be done under supervision of a qualified healthcare professional.
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A
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Renal failure
Kidney disease occurs when the kidneys permanently lose the ability to remove waste and maintain fluid and chemical imbalances in the body. Kidney disease may develop rapidly (over two to three months) or very slowly (over 30 to 40 years). The effectiveness of calcium salts vs. sevelamer in peritoneal dialysis has been reviewed. According to secondary sources, calcium carbonate or calcium acetate is equally effective as a phosphate binder for renal failure. Calcium citrate, however, increases absorption of aluminum, and is therefore not suggested for renal failure treatment.
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A
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Toxicity (magnesium)
Intravenous calcium is used in the treatment of hypermagnesemia (high levels of magnesium in the blood). Case studies suggest intravenous calcium may aid in the improvement of symptoms. Treatment of magnesium toxicity should only be done under supervision of a qualified healthcare professional.
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A
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Black widow spider bite
Calcium supplementation is used in the treatment of black widow spider bites to relieve muscle cramping in combination with antiserum, analgesics (pain relievers), and muscle relaxants. Treatment of a black widow spider bite should only be done under the supervision of a qualified healthcare professional.
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B
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Fractures (prevention)
A fracture is a break in a bone or cartilage, often but not always the result of trauma. Calcium supplementation may be effective in preventing fractures through the prevention of bone loss. Further studies are needed to validate these results.
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B
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Gastrointestinal tract and colorectal cancer prevention
Colorectal cancer is the most common gastrointestinal cancer and the second leading cause of cancer deaths in the United States. Colorectal cancer is caused by a combination of genetic and environmental factors, but the degree to which these two factors influence the risk of colon cancer in individuals varies. Most large prospective studies have found increased calcium intake to be only weakly associated with a decreased risk of colorectal cancer. Further studies are needed to verify these results. Treatment of colorectal cancer should only be done under the supervision of a qualified healthcare professional.
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B
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High blood potassium level
Calcium supplementation may aid in antagonizing the cardiac toxicity and arrhythmia (abnormal heart rhythm) associated with hyperkalemia (high blood potassium), provided the patient is not receiving digitalis drug therapy. Treatment of hyperkalemia should only be done under supervision of a qualified healthcare professional.
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B
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High blood pressure
Several studies have found that introducing calcium to the system may have hypotensive (blood pressure lowering) effects. These studies indicate that high calcium levels lead to sodium loss in the urine, and lowered parathyroid hormone (PTH) levels, both of which result in the lowering of blood pressure. However, one study found that these results did not hold true for middle-aged patients with mild to moderate essential hypertension. In the DASH (Dietary Approaches to Stop Hypertension) study, three servings daily of calcium enriched low-fat dairy products reduced systolic and diastolic blood pressure. This research indicates that a calcium intake at the suggested level may be helpful in preventing and treating moderate hypertension. Treatment of high blood pressure should only be done under supervision of a qualified healthcare professional.
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B
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Lead toxicity
A chelating treatment of calcium has been suggested to reduce blood levels of lead in cases of lead toxicity. Reduced symptoms have been observed in most, but not all, patient case reports and case histories. Adequate calcium intake appears to be protective against lead toxicity. Treatment of lead toxicity should only be done under the supervision of a qualified healthcare professional.
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B
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Preeclampsia
For the general population, meeting current suggestions for calcium intake during pregnancy may help prevent pregnancy-induced high blood pressure (PIH). Further research is required to determine whether women at high risk for PIH would benefit from calcium supplementation above the current recommendations. However, studies have failed to demonstrate an effect of calcium supplementation on the development of preeclampsia. Treatment of PIH should only be done under supervision of a qualified healthcare professional.
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B
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Premenstrual syndrome (PMS)
There is a link between lower dietary intake of calcium and symptoms of premenstrual syndrome. Calcium supplementation has been suggested in various clinical trials to decrease overall symptoms associated with PMS, such as depressed mood, water retention, and pain.
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B
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Seizures
Seizures are caused by uncontrolled electrical activity in the brain, which may produce a physical convulsion, minor physical signs, thought disturbances, or a combination of symptoms. According to case reports, nutritional deficiencies, including low levels of calcium may lead to changes in the electrical patterns of the brain and may increase the risk of seizures. Correcting calcium to normal levels in cases of hypocalcemia may be necessary. Further study is warranted.
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B
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Arrhythmia
An arrhythmia is an abnormal heart rhythm. The heart rhythm may be too fast (tachycardia), too slow (bradycardia), or irregular. Some arrhythmias, such as ventricular fibrillation, may lead to cardiac arrest if not treated promptly. According to anecdote and animal data, intravenous calcium has been suggested as a treatment for arrhythmias. Anecdote suggests, however, that in persons with heart diseases, injected calcium may increase the risk of irregular heartbeats. Clinical trials are warranted.
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C
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Bone diseases
Rickets and osteomalacia (bone softening) are commonly thought of as diseases due to vitamin D deficiency; however, calcium deficiency may also be another cause in sunny areas of the world where vitamin D deficiency would not be expected. Calcium supplementation is used as an adjuvant in the treatment of rickets and osteomalacia, as well as a single therapeutic agent in nonvitamin D-deficient rickets. Research continues into to the importance of calcium alone in the treatment and prevention of rickets and osteomalacia. Treatment of rickets and osteomalacia should only be done under the supervision of a qualified healthcare professional.
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C
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Bone loss (steroid-induced, prevention)
Calcium supplementation in patients on long-term, high-dose inhaled steroids for asthma may reduce bone loss due to steroid intake. Treatment using the prescription drug pamidronate with calcium has been shown to be superior to calcium alone in the prevention of corticosteroid-induced osteoporosis. Inhaled steroids have been reported to disturb normal bone metabolism, and they are associated with a decrease in bone mineral density. Results suggest that long-term administration of high-dose inhaled steroid induces bone loss that is preventable with calcium supplementation with or without the prescription drug etidronate. Long-term studies involving more patients should follow to confirm these preliminary findings.
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C
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Breast cancer prevention
Some studies have linked higher calcium and vitamin D intake with lower breast cancer risk. Further studies are needed. Treatment of breast cancer should only be done under the supervision of a qualified healthcare professional.
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C
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Cardiovascular risk reduction
A review of the effects of calcium on myocardial infarction and cardiovascular events suggested a statistically nonsignificant increased risk for stroke, and a statistically significant increased risk for myocardial infarction with calcium use. Other researchers, however, have pointed out multiple flaws with this review and that more evidence is needed. A prospective analysis of the effects of calcium supplementation in postmenopausal women in Finland appeared to increase the risk of coronary heart disease (CHD). A pooled analysis of cohort studies suggested a lack of increased risk of stroke with consumption of milk products.
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C
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Childbirth (preterm birth prevention)
Preterm birth is defined as a delivery that occurs prior to 37 completed weeks. It is a chief cause of perinatal mortality and morbidity around the world. Calcium supplementation has been suggested as a means of prevention of preterm birth.
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C
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Circulation
Circulation is defined as the course of the blood from the heart through the arteries, capillaries, and veins back again to the heart. Normalization of priming solution ionized calcium concentration improved the hemodynamic stability of neonates receiving venovenous extracorporeal membrane oxygenation (ECMO). Further study is needed in order to draw a firm conclusion.
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C
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Cystic fibrosis
Cystic fibrosis (CF) is a genetic disease characterized by the production of abnormal secretions, leading to the accumulation of mucus in the lungs, pancreas, and intestine. This build-up of mucus causes difficulty breathing and recurrent lung infections, as well as problems with nutrient absorption due to problems in the pancreas and intestines. Without treatment, CF results in death for 95% of affected children before age five; however, the longest-lived CF patient survived into his late 30s. Human studies have been conducted examining the role of calcium and vitamin D supplementation in subjects with CF. Further study is needed before a firm conclusion may be made.
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C
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Endometrial cancer prevention
According to a meta-analysis of epidemiological evidence, a statistically nonsignificant, inverse association between endometrial cancer and calcium intake has been noted. Further study is needed in order to draw a more firm conclusion about the utility of calcium in decreasing endometrial cancer risk.
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C
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Fall prevention
The utility of calcium in the prevention of falls, particularly in elderly populations, has been examined. Frequently calcium is used in combination with vitamin D. Further studies may be warranted.
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C
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Growth
Growth of very low birth weight infants correlates with calcium intake and retention in the body. It is possible that human milk fortifiers commonly used may have inadequate levels of calcium for infants of very low birth weight. Bone mineralization is also lower in very low birth weight infants at theoretical term than in infants born at term. Use of a formula containing higher levels of calcium has been suggested to allow improved bone mineralization in these infants. One study has looked at the effects of milk supplementation in young girls with low dietary calcium intake and found that after two years, increases in bone density could be observed mainly in the legs. More studies are needed before a conclusion may be made.
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C
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Hyperparathyroidism
In patients on hemodialysis, calcium supplementation may reduce secondary hyperparathyroidism (high blood levels of parathyroid hormone due to another medical condition or treatment). Treatment of hyperparathyroidism should only be done under the supervision of a qualified healthcare professional.
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C
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Mortality
The effects of calcium on mortality have been studied in various populations, including perinatal populations. The effects of vitamin D and calcium have also been studied. Although the effects of calcium on maternal mortality seem to be promising, further study is needed before a firm conclusion may be drawn.
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C
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Muscle strength
The effects of calcium on muscle strength are unclear. The available evidence is derived from combination studies; the effect of calcium alone is unclear. Further study is needed before a firm conclusion may be drawn.
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C
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Myocardial infarction
The evidence for the effects of calcium on myocardial infarction is mixed. One review of the effects of calcium on myocardial infarction and cardiovascular events suggested a statistically significant increased risk for myocardial infarction with calcium use. Other researchers, however, have pointed out multiple flaws with this review, and that more evidence is needed.
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C
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Oral mucositis
Calcium phosphate has been used in the treatment and prevention of oral mucositis. Further study is needed.
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C
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Osteomalacia / rickets
Rickets and osteomalacia (bone softening) are commonly thought of as diseases due to vitamin D deficiency; however, calcium deficiency may also be another cause in sunny areas of the world where vitamin D deficiency would not be expected. Calcium is used as an adjuvant in the treatment of rickets and osteomalacia. Research continues into the importance of calcium alone in the treatment and prevention of rickets and osteomalacia. Treatment of rickets and osteomalacia should only be carried out under the supervision of a qualified healthcare professional.
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C
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Ovarian cancer prevention
A meta-analysis of case-control studies examining the effects of dairy products and calcium on ovarian cancer risk found a lack of increased risk with dairy consumption. The analysis, however, did observe an increased risk for ovarian cancer with a lactose intake equal to three or more daily servings of milk. A nested case-control study found a statistically significant, inverse relationship between ovarian cancer risk and calcium intake. Further study is needed before a firm conclusion may be drawn.
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C
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Postpartum depression
Calcium has been suggested as a treatment for postnatal depression (PND) in humans. Further data, however, are lacking. Future research for PND prevention is warranted.
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C
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Post-surgical side effects (rectal epithelial hyperproliferation)
Following intestinal bypass surgery, fecal bile acids and fatty acids tend to increase, which may contribute to proliferative effects. In humans, calcium inhibited the proliferative effects, and reversed postsurgical proliferative changes. Further studies are needed in order to make a firm conclusion.
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C
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Type 2 diabetes
In clinical study, combining vitamin D with calcium demonstrated a reduced risk of type 2 diabetes, with the highest intake resulting in a 33% decreased risk. For interventional trials, in hypertensive nondiabetics, compared to placebo, 1,500 milligrams daily of calcium for eight weeks improved insulin sensitivity. While promising, further trials are warranted.
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C
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Weight loss
Diets with higher calcium density (high levels of calcium per total calories) have been associated with a reduced incidence of being overweight or obese in several studies. While more research is needed to understand the relationships between calcium intake and body fat, these findings emphasize the importance of maintaining an adequate calcium intake while attempting to diet or lose weight.
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C
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Cardiopulmonary resuscitation (CPR)
Cardiopulmonary resuscitation is the restoration of cardiac output and pulmonary ventilation following cardiac arrest and apnea, using artificial respiration and manual closed-chest compression or open-chest cardiac massage. Per the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science, routine administration of calcium for the treatment of cardiac arrest is no longer advised. Variable results have been observed in trials, and a beneficial effect on survival is lacking with the use of calcium.
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D
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Vaginal disorders
Stopping treatment with topical hormone replacement therapy and switching to treatment with calcium plus vitamin D made vaginal atrophy worse in one study. Increases in painful or difficult intercourse and urinary leaks were reported. Menopausal complaints of hot flashes and night sweats were also worse than before calcium plus vitamin D therapy.
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D
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