Taking calcium pills may not be such a great idea, according to new research by Johns Hopkins University School of Medicine. Researchers found that people who use such dietary supplements may be at greater risk of heart disease due to the build-up of calcium plaques in their coronary arteries.
In contrast, eating a diet that is high in calcium was found to be associated with a decreased risk of heart disease, indicating that the danger lies specifically with supplements rather than calcium in food.
"There is clearly something different in how the body uses and responds to supplements versus intake through diet that makes it riskier," said study co-author John Anderson from the University of North Carolina in a statement. "It could be that supplements contain calcium salts, or it could be from taking a large dose all at once that the body is unable to process."
The researchers decided to conduct their study after previous work revealed that much of the calcium contained in these supplements is neither incorporated into the skeleton nor excreted, suggesting it must be accumulating somewhere else in the body.
To investigate, they surveyed 2,742 people about the amount of calcium they consume in their diets and through pills. Participants also underwent two CT scans, 10 years apart, in order to monitor levels of calcium plaques in their coronary arteries.
At the end of the decade-long study period, people who consumed the highest amount of calcium – more than 1,400 milligrams a day – were considerably less likely to have developed calcium plaques than those who consumed the lowest amount of less than 400 milligrams a day.
While this information clearly indicates that a high calcium intake is beneficial for cardiovascular health, the picture changed dramatically when the researchers divided participants up into those that used calcium supplements and those that obtained their calcium exclusively through food.
Overall, the 43 percent of people that claimed to use supplements were 22 percent more likely to develop calcium plaques than those that didn’t. A full report of this study can be found in the Journal of the American Heart Association.
"Our study adds to the body of evidence that excess calcium in the form of supplements may harm the heart and vascular system," said study co-author Erin Michos from the Johns Hopkins University School of Medicine.
Therefore, while a daily calcium intake of between 550 and 1,200 milligrams is recommended in order to maintain healthy bones and teeth, it is clearly important to think carefully about which sources you are obtaining your calcium from.
3