Taken to heart: Calcium supplements may lead to cardiac problems

A new meta-analysis warns that when assessing whether to take calcium supplements, you may need to consider that the risks to heart health could outweigh the benefits, which mainly consist of enhancing bone mineral content and reducing fractures. Published in BMJ, the study analyzed data from a total of 29,000 participants in various prior studies who had taken calcium supplements either with or without vitamin D. Researchers measured their incidence of heart attacks and stroke and calculated that for every 1,000 women who take calcium supplements for five years, six extra cases of heart attack occur while only three fractures are prevented. Overall, the data show an increased heart attack risk of 25 percent and a 15 percent increased risk for stroke.

ACSH’s Dr. Elizabeth Whelan says these results are quite surprising “because older women have long been encouraged to take calcium supplements to prevent osteoporosis, but it looks like the risk of heart problems may outweigh the bone health benefits, at least for some women.”

Lead author Ian Reid, professor of medicine and endocrinology at New Zealand’s University of Auckland, warned supplement manufacturers that, “The forms of supplements we are using at the minute are measurably not safe, and I think that if industry ignores that fact, or refuses to engage, it may be opening itself up to liability in the future.” An industry spokesman, however, found fault with the study’s methodology and conclusions.

But ACSH’s Dr. Gilbert Ross believes that these results cannot be dismissed out-of-hand. “The data speak for themselves. While a meta-analysis is not necessarily a gold standard means of assessing such health effects, as a physician, I would consider this analysis ‘food for thought.’ It certainly warrants a randomized clinical trial to see if the results can be replicated. If a patient has serious risk factors for heart disease, I would take this into consideration when determining whether or not she really needs calcium. However, I wouldn’t automatically take women off calcium supplements because of this study.”