Calcium Supplements May Cause Heart Damage, Study Finds

In a 10-year study including more than 2,700 subjects, researchers found that calcium supplement users were more likely to experience plaque buildup in their arteries and damage to their hearts than other participants, according to the Journal of the American Heart Association. People who consumed high amounts of calcium through their diets, on the other hand, were apparently protected from these effects.

The researchers suggest that rather than offering health benefits, calcium supplementation may actually damage cardiovascular functions, particularly in older adults. Those in the study who took calcium supplements had a 22 percent higher risk of developing plaque buildup in their arteries than those who didn't.

So how did the study work?

Participants between the ages of 45 and 84 were initially surveyed about their eating habits and supplement use and were given basic medical tests. Ten years later, the researchers followed up with the subjects and conducted more tests.

And despite the fact that nutritional supplements are widely seen as a smart choice, they found that subjects who took calcium were more likely to have artery calcification, a hardening of the blood vessels which can cause health issues.

"Patients should really discuss any plan to take calcium supplements with their doctor to sort out a proper dosage or whether they even need them,” said Dr. Erin Michos, associate director of preventive cardiology at the Johns Hopkins University School of Medicine, in a press release.

“Ingested calcium supplements — particularly in older people — don’t make it to the skeleton or get completely excreted in the urine, so they must be accumulating in the body’s soft tissues,” said nutritionist John Anderson, professor emeritus of nutrition at the University of North Carolina at Chapel Hill and a co-author of the study.

The safest bet, the authors found, is to get calcium directly from foods high in the mineral, like leafy greens such as kale or broccoli.

“Based on this evidence, we can tell our patients that there doesn’t seem to be any harm in eating a heart-healthy diet that includes calcium-rich foods, and it may even be beneficial for the heart,” says Michos.

The study does not address the effects of foods that are "fortified" with calcium, rather than contain it naturally.

“When it comes to using vitamin and mineral supplements, particularly calcium supplements being taken for bone health, many Americans think that more is always better,” she continued. “But our study adds to the body of evidence that excess calcium in the form of supplements may harm the heart and vascular system.”

Many nutrition experts are critical of claims made in favor of vitamin and mineral supplements, arguing that the benefits have been exaggerated while the dangers have been downplayed.

The industry is largely unregulated by the government.

Marion Nestle, professor of food studies and nutrition at New York University, told Patch in an email that though she is skeptical of the health benefit claims made about supplements, we shouldn't be too confident in the results of a single study.

However, this study is consistent with what we know more generally about supplements.

"Studying single nutrients outside of their food or dietary context can be highly misleading, but most evidence points to the value of eating foods and shows little benefit from supplements," Nestle said.

She continued: "But we do love taking supplements even without evidence. They aren’t about science; they are about belief systems."

As Michos noted, it's most important for people to speak with their doctors before making decisions about their diet and health. But these types of studies do help build upon a larger base of knowledge, which can contribute to an informed decision-making process.

"The research is preliminary and needs further research to confirm or deny," said Nestle. "How worried should anyone be about taking calcium supplements? They don’t help with bone fractures much, but for heart disease that question needs more research to answer."

Read the full study>>

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