Side Effects of Calcium Supplements

Calcium is important for preventing osteoporosis and building strong teeth and bones. Calcium supplements are available for people who do not get enough calcium in their diets. While these supplements are considered safe, some side effects may occur. These side effects impact the digestive system and may make it necessary to switch supplement brands or reduce the amount of calcium taken each day.

Side Effects of Calcium Supplements Credit: Steve Mason/Photodisc/Getty Images


Calcium supplements can cause flatulence with regular use. Flatulence is air that passes through the digestive tract and through the rectum. Other common terms for this condition are gas and flatus. Flatulence may occur when calcium supplements are first taken and then cease once the body has adjusted to a daily dose of the supplement.


Constipation is a known side effect of taking calcium supplements. Taking one calcium supplement dose in the morning and the other dose in the evening may reduce stress on the intestinal tract. The editors of Prevention also recommend switching from calcium carbonate to calcium citrate. Calcium citrate seems to have less of an effect on the digestive system.

Drug Interactions

Calcium supplements may interact with prescription and over-the-counter drugs. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, calcium interferes with iron absorption and may reduce the absorption of tetracycline. If medications need to be taken on an empty stomach, they should not be taken at the same time as a calcium supplement.

Nausea & Vomiting

Nausea may occur if calcium supplements are taken without food or high doses of calcium are ingested. Severe nausea may lead to vomiting and other digestive symptoms. Take calcium supplements with food or switch to a lower dose of calcium to avoid side effects such as nausea and vomiting.


Belching can occur as a side effect of calcium supplements. Belching is the passage of air from the intestinal tract through the mouth. If belching persists, it should be reported to a physician. Switching supplement brands or taking smaller doses of calcium may eliminate this side effect.

Dry Mouth

Calcium supplements may cause dry mouth, which is a reduction in saliva. If taking smaller doses of calcium does not help to eliminate this side effect, it should be reported to a medical professional. Persistent dry mouth can lead to difficulty swallowing, digestive problems and reduced taste.

Stomach Pain

Stomach pain may occur as a side effect of calcium supplements. Taking the supplement with food or taking small doses in the morning and evening may be enough to keep this side effect from occurring. If stomach pain persists, a different dosage or form of calcium may be needed. Calcium citrate may be used instead of calcium carbonate to avoid digestive side effects.

Loss of Appetite

Calcium supplements may cause a loss of appetite because of the nausea, vomiting and stomach pain that can occur. Once these side effects are resolved, the appetite should return to normal. If loss of appetite is persistent, a different supplement may be needed.

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