Q: I'm healthy, but a CT scan of my coronary arteries revealed extensive calcium deposits, which my doctor said can trigger a heart attack. Could the deposits have been caused by the calcium supplements I've taken?
A: There’s no convincing evidence that the calcium you get from food or supplements increases calcium deposits (calcification) in plaque in coronary arteries and other blood vessels.
Coronary calcification is a marker for increased cardiovascular risk. Calcium is deposited in plaque as part of the atherosclerosis process, which is caused largely by chronic inflammation in blood vessel walls. The body is very good at regulating calcium in the blood (except in people with certain metabolic or kidney conditions); calcium in the blood does not simply build up in artery walls.
Though several studies have suggested that calcium supplements increase the risk of coronary artery disease, most research has found that they do not affect arterial calcification or coronary risk. For instance, in 2012 the long-running Framingham Offspring Study found that people who consumed the most calcium from food plus supplements (as much as 3,000 milligrams a day) did not have more coronary calcium. This has been confirmed by subsequent research.
It’s not known what steps can reduce arterial calcification—other than the advice for reducing atherosclerosis, such as intensive dietary changes and weight loss.
By the way, we don’t recommend routine screening for calcification, which is done with special CT scans, even though some doctors advise it. Such screening is still being debated because it’s unclear how much information it provides for predicting heart disease beyond an evaluation of standard risk factors. However, if you are at intermediate coronary risk and it’s unclear whether you should start statin therapy, screening for calcification may help you and your doctor decide.
See also: Calcium in the Spotlight.