Do Calcium Supplements Cause Heart Attacks in Women?
Did you see this worrisome headline? “Older Women Who Take Calcium Supplements to Maintain Bone Strength May have an Increased Risk of Heart Attack.”  When we all thought calcium supplements were relatively safe, we now find out that high dosages of calcium supplements may adversely influence vascular health.
Researchers at the University of Auckland in New Zealand evaluated 1471 healthy post-menopausal women, average age 74, for a period of 5 years.  Of them, 732 were given a daily calcium supplement and 739 were given a placebo. Participants received either 1 gram of elemental calcium citrate daily (Citracal) or identical placebo.
They were asked to take two tablets (each containing 200 mg of elemental calcium) before breakfast and three in the evening. Over the next few years, heart attacks were more common in the women taking the calcium supplements.
Based on these results, doctors and patients are now presented with a very difficult challenge. Many women take calcium supplements to try to prevent osteoporosis. But calcium supplements elevate blood calcium levels, possibly accelerating vascular calcification, and leading to heart attacks. At what level of calcium supplement intake do the benefits of osteoporosis prevention or treatment outweigh the possible risks of heart attacks?
As a physician, I would like to see a few more studies regarding the role of calcium supplements and heart attack rate. Perhaps the results of this study were a fluke and other studies will not find the same association. Assuming that there is such an association, recommending calcium supplements for post-menopausal osteoporosis prevention becomes quite difficult.
I don’t have absolute answers on this issue, but, for the time being, a reasonable balance would be to reduce one’s calcium intake from supplements. If you are taking 1200 mg a day, you may wish to drop to 800 or 1000 mg. If you are taking 800 a day, you may wish to drop to 600 mg.
Discuss the results of this study with your doctor. Both of you could come to a mutually satisfying decision regarding the appropriate dosage in your particular case. Until there is clear-cut evidence, it is likely that doctors and researchers will have different opinions on this topic.
- 1. Reuters/healthNews.
- 2. Bolland MJ et al. Brit. Med. J. 2008 Jan 15.