Calcium carbonate products are most often recommended because they contain a higher percentage of elemental calcium and they are cost-effective. Calcium carbonate should be taken with food or immediately after eating to ensure adequate absorption. Antacids such as Tums and Rolaids are perfectly acceptable forms of calcium and are marketed as such. Calcium supplements are absorbed most efficiently at individual doses of 500 mg calcium or less. A limited amount of calcium can be transported every hour, so advise your patients to take divided doses throughout the day rather than one large dose.
Vitamin D is also important for the absorption of calcium.
Calcium and vitamin D can be combined in one supplement, although this is not necessary. Health information from the U.S. often recommends calcium citrate as the best source of calcium. However, calcium citrate is not widely available in Canada. It is more likely to be found in herbal products, as a single entity or in combinations. Swiss Herbal manufactures a plain calcium citrate tablet.