“Calcium Doesn’t Boost Bone Health” was the headline in a recent Newsweek article, implying that perhaps that glass of milk wasn’t as important as our parents made us believe. This statement stems from a recent meta-analysis—a statistical review of many independent studies—published in the British Medical Journal. Although the headline may be surprising, it is correct in suggesting that if you are trying to increase your bone mineral density (BMD), supplements may not be the best choice.
What the Research Shows
The meta-analysis looked at various calcium supplementation studies that focused on BMD, an important factor in preventing bone fractures. This is especially important for an aging population, in which each year 250,000 people are hospitalized for hip fractures, 75% of whom are females. The meta-analysis included many studies of postmenopausal women (whose risk for fractures is higher) and concluded that calcium supplementation only slightly increased BMD (2% at best), which doctors would say is not enough to reduce the risk of fractures. This was true even after accounting for the fact that some people also take vitamin D supplements to aid calcium absorption.
What Other Research on Calcium has Shown
A separate meta-analysis published in the Journal of the American Medical Association examined links between calcium and cardiovascular disease. It found that higher supplemental calcium intake was associated with a higher risk of cardiovascular disease, particularly in men. However, this was not true in people getting calcium from their diet. One possible explanation for all of this is that the body cannot absorb high amounts of supplemental calcium, and excess amounts may lead to calcification of arteries.
More to the Story…
Most of the research suggests calcium supplements may not be as helpful as we once thought. However, it would be interesting to see a large meta-analysis on the effect of magnesium, another vital mineral for bone health that also aids in calcium transport in the body. Foods high in calcium, such as leafy greens, also have high levels of magnesium and thus aid in calcium absorption. This could be why high dietary calcium is less of a cardiovascular disease risk. Furthermore, most studies of supplemental calcium have only looked at postmenopausal women. But, as with most conditions, it is likely better to prevent bone mineral loss early on (in the premenopausal stage). Research on this has been inconclusive, with some studies showing that greater calcium intake increases bone density, while others show that even a low-calcium diet does not affect bone density.
Our Take-Home Message
Calcium is an important micronutrient in our diet, having many roles. However, it may not be best in supplement form. As we mentioned in our recent article on omega-3 supplements, the best way to meet your nutritional needs is generally through a varied diet. For calcium, aim for a diet with an adequate amount of dairy and leafy greens, such as kale and broccoli.