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Calcium Carbonate Or Calcium Citrate For Your Osteoporosis Treatment?

Calcium carbonate is slightly more effective than calcium citrate if taken with meals. But research suggests that calcium citrate malate (CCM) provides the more absorbable non-food source of calcium.

Calcium supplements are often the first thing we think of when trying to treat osteoporosis. But choosing the right formula can be very confusing. The most common types of calcium supplements are as follows.


Calcium carbonate is the most common source of calcium used to prevent osteoporosis. Eight-five percent of all calcium supplements sold in the US are made from calcium carbonate-including antacids such as TUMS. It is less expensive than other forms of supplemental calcium and is widely available in tablets, capsules and chewables. Unrefined versions appear in dietary supplements as bone meal, oyster shell, limestone, and dolomite (clay).

Calcium carbonate provides about 40% elemental calcium, and the elemental calcium is about 26% absorbable. Because it provides such a large portion of elemental calcium, pills can be smaller than required for other forms of tablets. A supplement with 500 mg of elemental calcium provides 130 mg of absorbable calcium... if taken with meals.

Caution must be taken regarding the quality of the calcium in the supplement. Depending on how the tablet is manufactured, some pills have been found to disintegrate and dissolve improperly, which could interfere with absorption. The solubility of calcium pills can be evaluated by putting a tablet in a half cup of vinegar and stirring occasionally. After half an hour all of the tablet should be dissolved.


Research suggests that many North Americans lack adequate stomach acid to break down and absorb sufficient calcium. Chelated calcium is bound to an organic acid (citrate, citrate malate, lactate, gluconate, aspartate, or orotate) in order to facilitate absorption. But chelated calcium offers both advantages and disadvantages compared with calcium carbonate.

Advantages: Certain forms of chelated calcium (calcium citrate and calcium citrate malate) are widely thought to be significantly better absorbed and more effective for osteoporosis treatment than other forms of calcium. However, while some studies support this belief others do not. The discrepancy may be due to the particular products used in the studies, as some calcium carbonate formulations dissolve better than others.

Disadvantages: Chelated calcium is much more expensive and bulkier than calcium carbonate-with the result that pills are larger than other compounds and more pills must be taken to get sufficient calcium. Five or six large capsules may be required to achieve the desired intake, which some people find troublesome.


Calcium citrate is a combination of calcium and citric acid. Because stomach acids are needed for calcium to be absorbed by the body, citric acid (from fruits) provides an acidic environment for improved calcium absorption.


Compounds such as fumarate, malate, succinate and aspartate (called Krebs cycle intermediates) can be used in combination with calcium citrate to help increase the body’s absorption of calcium and other minerals.


CCM is composed of calcium and two organic fruit acids, citric acid (from citrus fruits) and malic acid (from apples), both of which help to increase calcium absorption. Because of their similarity in both name and structure, CCM can be confused with calcium citrate, but they are not the same. Several studies on post-menopausal women over the age of 55 found that CCM resulted in 40% less bone loss when compared to a diet with ordinary calcium carbonate supplementation.


Coral calcium is essentially calcium carbonate derived from dead sea coral (Live coral is protected by international law.) It supplies calcium, magnesium and numerous other essential trace minerals that support body processes but there is limited data available on solubility and absorbability of this calcium source. There is little evidence at this time that coral calcium is superior to other forms of calcium and there is also concern about unacceptable levels of lead in coral calcium.


MCHC, a variation on bonemeal made from cow bones, has attracted attention because of studies reporting increases in bone mass in people with certain conditions and better effects on bone than calcium carbonate. Similar positive studies exist using CCM but unlike CCM, MCHC has only occasionally been compared with other forms of calcium. In comparison research, MCHC fared poorly in terms of solubility, absorption and effect on calcium metabolism.


Some doctors have expressed a concern that antacids that contain calcium (like Tums®) interfere with the body's absorption of calcium. However, this is not the case. Calcium carbonate, the principal ingredient in Tums provides significant (though not optimal) absorbable calcium. Other forms of calcium that might be more bio-available, such as calcium citrate, also act as antacids. The form of calcium associated most consistently with best bio-availability, CCM, is itself an antacid despite the fact that it is used almost exclusively as a source of calcium.

Prescription medication for acid reflux works very differently than the above antacids and will limit calcium absorption and accelerate bone loss if taken for long periods.

For less than $30 a year, Puritan's Pride Bone Care will provide the recommended levels of calcium carbonate, vitamin D, magnesium and vitamin K needed to optimize bone health.