We all grew up knowing that we needed calcium for strong bones and teeth. "Drink your milk," moms would say. But not everyone drank milk, and many of us moved away from milk when we became adults.
Today, the most common reason to add a calcium supplement to a diet is to prevent osteoporosis (bone loss). Osteoporosis is primarily a concern of women, especially White and Asian women. To help avoid osteoporosis, physicians often suggest a calcium supplement, and many women decide to take them on their own, as well. But which kind is best?
Calcium supplements are available in many forms: calcium carbonate, calcium citrate, and calcium citrate/malate, as well as bone meal, coral calcium, and oyster shell. Many medical studies investigating calcium have been conducted, and as with all studies, some have indicated conflicting results. Most seem to agree on the following few aspects.
Calcium carbonate offers 40% elemental calcium. It is a good choice for those concerned about cost and those who want to take fewer pills each day. It may be absorbed slightly less well than some other forms, but appears to be absorbed as well as the calcium in milk. (Dairy foods are still the best source of calcium.)
Calcium citrate offers 24% elemental calcium. Calcium citrate may be absorbed at a better rate than calcium carbonate, but it is necessary to swallow more pills each day to reach the recommended 1000 mg, making it a more expensive and more cumbersome option.
The best absorption seems to be from calcium citrate/malate (CCM). Although similar, it should not be confused with calcium citrate.
MCHC, a form of bone meal, should be mentioned, as studies have shown it to increase bone mass better than other forms. However, MCHC rates poorly in solubility and absorption. There is little evidence to indicate that either coral calcium or oyster shell is superior to the other forms of calcium discussed here.
A question that comes up from time to time concerns whether antacids such as Tums® and similar products can be used as calcium supplements. In reality, nearly all forms of calcium, including CCM and calcium citrate, act as antacids, and concerns about interference from this property are not valid.
Finally, all calcium supplements are absorbed better when they are taken with meals, and adding supplemental vitamin D (400 IU) is also recommended.