Can calcium supplements increase my risk of heart attack?

While more research is needed, heart attack risk may rise for women when they begin calcium supplementation (with or without vitamin D), according to a recent analysis of research study data from the Women’s Health Initiative and other studies.

A heart attack is caused when blood flow through the coronary arteries that supply blood to your heart is cut off. In coronary artery disease, plaque -- a fatty substance made up of cholesterol, calcium, and other materials -- builds up in the coronary arteries. The plaque can narrow the arteries, and vulnerable plaques can rupture, causing a blood clot to form that can block blood flow.

Because calcium is one of the components of plaque, various researchers have conducted studies to see if calcium supplements can contribute to heart attacks. A study in 2011 in the British Medical Journal analyzing data from the Women’s Health Initiative (a large, long-term study sponsored by the National Heart, Lung, and Blood Institute) found that women who began supplementation with calcium were more likely to have a heart attack over a five-year period (approximately 6 heart attacks per 1,000 women). Women who had already been taking calcium before joining the study did not have an increase in heart attack risk. So researchers theorize that a sudden change in calcium intake may increase heart attack risk.

These findings reflect the findings of only one study. In fact, other studies have found mixed results. For now, you may want to discuss any concerns you have with your physician and weigh your personal risk of bone fractures versus your risk for a heart attack when considering supplementation.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.