Last week, my students in my osteoporosis prevention class were all talking about the news that calcium supplements may cause heart attacks. So I promised them I’d research this and tell them what I found out. (There is a benefit to having been a librarian.)
I also found some recommendations from American Bone Health that seem to be reasonable guidelines to follow.
Here’s what I found
I read articles from several sources. (The list is below.)
Here are a couple of hightlights:
The study specifically excluded research on calcium administered with vitamin D. (Everyone I’ve talked to who is taking calcium supplements is also taking vitamin D – on the recommendation of their doctors.)
Comparison with other studies
“A body of evidence related to the current work comes from studies comparing coadministered calcium and vitamin D supplements with placebo, which were excluded from our meta-analysis. Recently, the Women’s Health Initiative reported that calcium and vitamin D had no effect on the risk of coronary heart disease or stroke. The findings of that study might differ from ours for several reasons. The Women’s Health Initiative used low dose vitamin D supplements, and vitamin D deficiency has been associated with increased risk of cardiovascular disease and vitamin D supplementation with decreased mortality.”
Conclusions “In summary, randomised studies suggest that calcium supplements without coadministered vitamin D are associated with an increased incidence of myocardial infarction. The vascular effects of calcium supplements, especially without vitamin D, should be studied further.”
The real conclusions seem to me to be that 1) calcium supplements without associated vitamin D supplements may cause heart attacks and 2) doctors should be prescribing calcium supplements after determining if there really is a calcium deficit. More is not better
The most reasonable recommendations I found came from American Bone Health.
“Before you take a daily calcium supplement, know how much calcium you are eating in your diet and DO NOT exceed your daily requirement.”