Osteoporosis affects about 44 million Americans over 50 years old, according to the National Osteoporosis Foundation, with 80 percent of women affected and 20 percent of men. Luckily, calcium carbonate can help prevent or reduce the effects of osteoporosis. However, complications and health problems can occur with calcium carbonate if you are not careful in how you take the supplements and which brand you buy.
A naturally occurring element, calcium carbonate exists in oyster shells, limestone and chalk, and becomes calcium supplements and antacids through manufacturing. According to MayoClinic.com, calcium carbonate contains 40 percent elemental calcium while the more refined calcium citrate contains 21 percent. Your calcium carbonate may or may not be combined with vitamin D or magnesium to help with absorption.
Your stomach acids break down and dissolve calcium so it can enter your bloodstream. If you don't take calcium carbonate with food, your body won't be able to absorb it, and you may end up not getting the amount of calcium you need, according to a study in the December 1990 "Journal of American College of Nutrition." Moreover, your body can only absorb so much calcium at one time, somewhere between 500 and 600 mg.
Too Much Calcium
Depending on your age and your risk factors for developing osteoporosis, the amount of calcium you need in your diet each day varies from 1,000 mg per day to 1,200 mg if you are over 18, according to a 2010 report by the Institute of Medicine. The institute also lists upper limits for calcium, which the researchers stress are not the amount you should aim for, but rather the amount you should be careful not to reach.
If your calcium levels from food and supplements exceed 2,500 mg for adults 19 to 50 and 2,000 mg for adults over 50, your risk of developing kidney stones increases. Other overdose symptoms can include stomach or bone pain, constipation, confusion, headaches, nausea or comas.
Because the U.S. Food and Drug Administration does not regulate dietary supplements, like vitamins and calcium supplements, some calcium carbonate brands may contain toxic metals, such as lead. Check the label on your supplement bottle for the words "purified" or "USP Verified Mark," which both indicate that the calcium has been tested.
Check with your doctor about how calcium carbonate might interact with other drugs you take. For example, the calcium may interfere with antibiotics, thyroid medicine, iron supplements or antacid medications. Other side effects include burping and excess gas, dry mouth, increased urination, loss of appetite and a metallic taste in your mouth.