Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.
Avoid in individuals with a known allergy/hypersensitivity to calcium supplements or any of their ingredients. Some people are lactose intolerant. Dairy products contain lactose and dairy products are a common food source of calcium. Lactose intolerance can cause cramping, bloating, gas, and diarrhea. Lactose intolerance affects the population in varying degrees.
Calcium supplementation is likely safe when used orally and intravenously, as recommended by a qualified healthcare professional. It is also likely safe when used orally and appropriately in pregnancy and lactation, as recommended by a qualified healthcare professional. Routine dietary intake and supplementation in recommended doses are not associated with significant adverse effects.
Excretion of abnormally large amounts of calcium in the urine is a well-established side effect of administration.
Low levels of calcium in the blood and tissues can cause sensations of tingling, numbness, muscle twitches, and muscle spasms (tetany). This condition is more likely to be due to a hormonal imbalance in the regulation of calcium rather than a dietary deficiency.
Excess calcium in the blood can be without symptoms or it can cause loss of appetite, nausea, vomiting, constipation, abdominal pain, dry mouth, thirst, frequent urination, and calcium deposition in the heart and kidneys. More severe hypercalcaemia may result in confusion, delirium, coma, and if not treated, death. Hypercalcaemia has been reported only with the consumption of large quantities of calcium supplements usually in combination with antacids, particularly in the past when peptic ulcers were treated with large quantities of milk, calcium carbonate (antacid) and sodium bicarbonate (absorbable alkalai).
Avoid high doses of calcium without food in those who are prone to the formation of calcium-containing kidney stones, as calcium supplementation in the absence of food may be associated with an increased risk of calcium oxalate stone formation. Consult a qualified healthcare professional if you are prone to kidney stones before using calcium supplements.
Use cautiously in those with achlorhydria (absence of hydrochloric acid or HCl in gastric juices) as low levels of gastric acid during digestion reduces urinary phosphate and calcium excretion. It may be advisable to take calcium carbonate with food to stimulate gastric acid production. Consult a qualified healthcare provider.
Avoid cigarette smoking, as this decreases intestinal calcium absorption and may lead to decreased bone mineral density.
Use cautiously if taking large amounts of vitamin D. Excess calcium in the blood (hypercalcaemia) can cause nausea, vomiting and calcium deposition in the heart and kidneys. This usually results from excessive doses of vitamin D and can be fatal in infants. Consult a qualified healthcare provider.
Use cautiously in individuals with heart arrhythmias and ventricular fibrillation (irregular heart beating). Large fluctuations in free calcium during intravenous calcium infusion can cause the heart to slow down or beat too rapidly. Although calcium appears to have benefits on bone density and osteoporosis, calcium should be used cautiously in postmenopausal women due to an increased possibility of cardiovascular side effects. Consult a qualified healthcare provider.
Pregnancy and Breastfeeding
The Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food, and Nutrition Board suggests that current calcium recommendations for non-pregnant women are also sufficient for pregnant women because intestinal calcium absorption increases during pregnancy.
Pregnant women are especially vulnerable to accelerated bone turnover due to the physiologic stress of pregnancy and lactation. Studies indicate that pregnant women should take calcium supplements to prevent bone density loss. The National Academy of Sciences recommends that women who are pregnant or breastfeeding consume calcium each day. For pregnant teens, the recommended intake is higher.
Consult a qualified healthcare professional to determine dosing during pregnancy and breastfeeding.