Calcium carbonate is fast-acting and potent. The compound is a white powder made from chalk, bones, and shells and was widely used by German physicians in the middle 1800s and later as part of Dr. Sippy's regimen. Like sodium-based antacids, these compounds are good in low doses for short-term relief but should not be used in higher does or long term.
Too much calcium can damage the kidneys and lead to calcium deposits in the eyes and skin. Ironically, it was the Sippy diet that brought attention to this side effect and was one of the reasons it fell out of favor. Another problem with calcium-based compounds is that while they initially work and neutralize stomach acid, calcium itself can stimulate stomach acid.
So what do we recommend? Calcium is an essential mineral for healthy bones and teeth and to prevent osteoporosis in postmenopausal women. Taking just one calcium-containing antacid tablet a day will help prevent this serious bone disease if taken prior to the onset of menopause. But heavy use of these products may damage the kidneys, a fact that far outweighs the benefits of preventing osteoporosis. We therefore believe that high doses of antacids containing calcium should not be used routinely, except under the careful supervision of a physician.