Can Calcium Supplements Cause Heart Attacks?

The British Medical Journal presented a meta-analysis conducted by a research group in New Zealand of 15 studies on calcium supplementation without vitamin D.  Calcium supplements are widely prescribed for the prevention and management of osteoporosis and have been shown to modestly reduce fracture risk in high risk populations.  This analysis, however, found an increase risk of heart attacks, vascular events and death with lone calcium supplementation.  The possible mechanism lies in the increased amount of calcium in the blood that might be adhering to arterial walls. 

The scariest findings?  While for every 1000 patients treated with calcium 26 fractures were prevented, 14 additional patients had heart attacks, 10 had strokes and 13 died.  Not exactly the type of trade-off many would make.  Combine these numbers with an association of increased prostate cancer risk in men with higher calcium intake and the concept of calcium supplementation might ultimately be overhauled. 

It should be noted, however, that these findings are not necessarily directly applicable to all patients.  First, the study excluded the use of vitamin D, which is generally given along with calcium.  Additionally many patients with osteoporosis who take calcium also take bisphosphonates that would effectively lower the amount of circulating calcium that would be available for deposition into blood vessels.  The bottom line is that if you are a man, you probably should avoid calcium supplements altogether and if you are a woman, you should take them if at high risk, but not without vitamin D and or bisphosphonates.

To read the full British Medical Journal report, click here.