Effective calcium supplementation is a lifestyle commitment. Safety All non-chelated calcium salts may cause constipation, but in the elderly, certain salts, including calcium carbonate, have been shown to cause diarrhea. Other side effects of calcium salts include flatulence, nausea, and bloating. Calcium chloride may produce more gastrointestinal irritation than other forms of calcium, and yet the hydrochloric acid in the stomach enters into a chemical reaction with all soluble forms of calcium salts to create calcium chloride. Calcium carbonate, the source of the antacid mentioned above, is known to cause rapid and potent neutralization of gastric acid, but it is not recommended for prolonged use, due to potential for systemic side effects.
Calcium carbonate is associated with acid rebound.
It induces gastric secretion that is markedly increased by food. It has been shown to induce gastric hypersecretion for three to five and one half hours after ingestion. This acid rebound is most likely due to local effect on gastrin producing cells by ionized calcium. Therefore, all salt forms of calcium will produce some gastric irritation. The acid neutralization reaction shown previously forms the basis for calcium carbonate's effectiveness as an antacid.