Calcium, an essential nutrient, is more abundant than any other mineral in your body. Most of it is in your skeletal system. While overdoses of calcium, hypercalcemia, or calcium poisoning can occur from supplements, it has not been known to occur from food.
Besides being a major part of your bones, calcium participates in the normal function of your heart, muscles and nerves. Calcium occurs in many foods, but because many Americans need more calcium than they get from their diet, they may benefit from taking calcium supplements, which are widely available in different forms and dosages. In certain circumstances, supplements can lead to excessive levels in the body and symptoms of overdose.
Hypercalcemia has only been reported from the use of large amounts of calcium supplements, usually combined with antacids. This was a problem when the treatment of peptic ulcers involved taking calcium carbonate, sodium bicarbonate and milk. Mild poisoning may be asymptomatic or have effects such as nausea, vomiting, constipation, appetite loss, dry mouth, thirst, abdominal pain and frequent urination. Severe effects include confusion, delirium and coma. If hypercalcemia remains untreated, it can result in death.
For optimum bone health, the Recommended Dietary Allowance for calcium in an adult is 1,000 mg a day. Women in the U.S. typically get less than this. Although the calcium from dairy foods is generally well absorbed, the calcium from other food sources may not be usable by the body. Recommended calcium levels for various disease conditions is usually higher than the RDA. For example, an upper level of about 1,200 mg is recommended for high blood pressure, notes Linus Pauling Institute.
Tolerable Upper Intake Level
You should not exceed the tolerable upper intake level for calcium. For adults, the UL is 2,500 mg per day. If you are 51 or older, you should not take more than 2,000 mg. Calcium supplements have also been known to interact with medications like calcium channel blockers, digoxin, blood pressure medication and tetracycline. Consult your doctor if you want to take calcium supplements but take other medications.