Calcium supplements are thought to be good for the bones, but a new study warns they might be bad for the heart.

A report released Friday in the journal Heart found an alarming result: taking a calcium supplement to prevent bone loss puts people at a significantly greater risk for heart attacks. The 24,000 participants in the study, all between the ages of 35 and 64 and taking calcium supplements regularly, were found to be a whopping 86 percent more likely to have a heart attack than those who did not take supplements.

According to the study, “Calcium supplements have been widely embraced by doctors and the public on the grounds that they are a natural and therefore safe way of preventing osteoporatic fractures. We should return to seeing calcium as an important component of a balanced diet.”

Dr. Matt Lederman, featured in Forks Over Knives, advises, “There are often unintended consequences when taking nutrients in isolation. The research to date shows that the amount of calcium found in a whole-food plant-based diet is adequate – and that more isn’t necessarily better.”

The authors of the study noted that excessive calcium, a common side effect of taking calcium supplements, is where the harm may begin.

Says Lederman, “For good bone health, the most important factors are eating a healthy plant-based diet, getting an adequate amount of sunshine, and doing strength-oriented exercise.”