Calcium supplements may increase the risk of heart damage and plaque buildup in arteries, even though a diet high in calcium-rich food appears to help protect the heart, a study concludes.
The analysis is based on 10 years of study of more than 2,700 people.
The researchers caution that their work, published in the Journal of the American Heart Association, documents an association between calcium supplements and atherosclerosis. It does not prove cause and effect.
But they say the results add to growing scientific concern about calcium supplements, often taken by aging persons to prevent bones from becoming brittle; they urge patients to consult with a knowledgeable physician before using them.
“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,” says Erin Michos, associate director of preventive cardiology and associate professor of medicine at Johns Hopkins University. “But our study adds to the body of evidence that excess calcium in the form of supplements may harm the heart and vascular system.”
An estimated 43 percent of US adults take a supplement that includes calcium. Earlier studies showed that calcium taken that way, particularly in older people, doesn’t all “make it to the skeleton or get completely excreted in the urine, so … must be accumulating in the body’s soft tissues,” says nutritionist and study coauthor John Anderson of the University of North Carolina Gillings School of Global Public Health. Scientists also knew that as a person ages, calcium-based plaque builds up in the aorta and other arteries, impeding blood flow and increasing the risk of heart attack.
