Calcium is present throughout the body as a necessary component to having strong teeth and bones. As the most abundant mineral in the body, calcium is indispensable in helping muscles, nerves, the heart and other systems function. Normally, calcium side effects are few and rarely occur, because it is naturally found in the body. Almost all calcium side effects happen as a result of taking dietary supplements; dietary calcium is usually considered safe. Calcium side effects usually center on the gastrointestinal, renal or cardiovascular systems and are the result of having either too much calcium present in the body, mostly from supplementation, or too little calcium in the body, sometimes the result of disease.
The most common side effect that people taking calcium supplements encounter is constipation. When taken in excess, the supplements can interfere with the removal of body wastes. Taking too much of this mineral can throw off the body’s chemical balance. Other gastrointestinal problems that might be encountered are bloating, gas pains, belching, cramps and an upset stomach.
One of the more serious calcium side effects can be its effects on the renal system. Taking high doses of calcium over an extended period might increase the likelihood of kidney stones forming. In high doses, considered by medical researchers to be doses of over 2,000 milligrams per day, calcium is toxic to the kidneys.
The cardiovascular system might also be put out of balance by an excess of calcium. Research indicates that an increased risk of heart attack is one of the possible side effects of calcium supplementation, but some scientists have disputed these findings. Taken in excess of what the body needs, calcium might accumulate in the blood vessels and in the heart muscle and, as a result, cause an abnormal heart rhythm.
One of the lesser-known calcium side effects is interference with the absorption of other minerals as well as some medications. Calcium can interact with a variety of antibiotics and lessen their effectiveness. Depending on the type of heart medication, this mineral also can either diminish or increase the effects of the medicine. Calcium might interfere with the absorption of blood pressure medications as well. Finally, calcium is known to decrease the absorption of some other minerals, such as iron and zinc.
Calcium supplementation, however, does have many positive effects on the body. It is used to treat osteoporosis and prevent bone loss. Among other benefits, research suggests that calcium is helpful in controlling high blood pressure and reducing the risk of both stroke and cancer of the colon. A doctor should be consulted before a person takes calcium supplements.