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Do Calcium Supplements Cause Heart Disease?

Do Calcium Supplements Cause Heart Disease?

Health and Wellness

February 24, 2013

Supplemental calcium intake is associated with increased cardiovascular disease (CVD) mortality in men, but not in women, according to a recent study from the National Institutes of Health (NIH) and published in the Journal of the American Medical Association Internal Medicine. The study was comprehensive and followed participants over a 12 year period. At baseline, supplements containing calcium were used by 51% of men and 70% of women. Dietary calcium, however, had no CVD effect on either men or women.

Calcium supplement use is widespread in western countries, especially among the elderly. While calcium’s role in the prevention and treatment of osteoporosis is well documented, little is known about non-skeletal outcomes. To make matters more confusing, several recent studies have shown links between calcium supplementation and CVD, even among women. And there have also been studies that show an inverse relationship between calcium supplement use and CVD mortality.

“In our study, we found that compared to men who did not report taking calcium supplements, men who reported taking 1000 mg per day were 19 percent more likely to die of heart disease, but we did not observe a relationship between calcium supplementation and risk of cardiovascular death in women,” says Dr. Qian Xiao, study author.

So why are men at higher risk? The authors think that more studies are needed. Men were more likely to start taking calcium supplements at a later age than women. One possibility is that women, who use calcium supplementation more regularly and at an earlier age than men, have achieved a sort of calcium balance with stable calcium levels long before the study was conducted. Therefore, the effects of supplementation possibly appeared less profound.

“Our study is based on observation – it is not designed to determine cause and effect. Although we observed an increased risk of death from heart disease in men who took supplements containing calcium, we cannot say for sure that it was a result of using calcium supplements. Individuals should talk with their health care provider to discuss their diet and use of calcium supplements, prior to beginning a regimen,” says Xiao.

Even though the National Osteoporosis Foundation (NOF) revealed new research in December that found no statistically significant link between calcium supplementation and increased risk of heart disease, NIH researchers warn against ruling out the possibility that supplemental calcium could be associated with cardiovascular mortality in women. 

“Further studies are needed to clarify the relationship between calcium intake and risk of death from cardiovascular disease. Particularly, studies designed to look at cardiovascular endpoints. These studies may also clarify the underlying mechanism for the difference we observed between men and women. Calcium is an important nutrient that is involved in many physiological processes. Supplementation with calcium is known to benefit bone health, particularly in older women,” says Xiao.

Heart disease is the leading cause of death for both men and women. About 600,000 people die of heart disease in the United States every year. About 10 million Americans have osteoporosis and about 34 million are at risk for the disease. Dietary calcium found in low-fat dairy foods, beans, and green leafy vegetables, is still considered the best and safest source of calcium health benefits.