Calcium Supplements May Risk Heart Health in Women

April 20, 2011

Researchers advise further studies and receiving calcium from food instead of supplements.

A recent study has uncovered evidence that women taking calcium supplements could be at an increased risk of harming their hearts…but that doesn’t mean that the nail in the proverbial coffin of supplements is hammered into place just yet.

As senior study author, Dr. Ian Reid, explained, "There is a lack of consensus at the present time as to what recommendations should be regarding the use of calcium supplements."

It was reported that the issue with the results, it seems, is that they could have been altered by the fact that many of the subjects in the study were previously taking supplements on top of what was prescribed by the authors; so while the study results seem rather conclusive, there is plenty of room for argument.

The randomized, placebo controlled study of 36, 282 postmenopausal women evaluated the affect of calcium with and without vitamin D on women’s heart health. The women were placed into a placebo or supplement group; the supplement group received 1g calcium and 400 IU vitamin D daily for seven years.

Unfortunately, only forty-six percent of the 36, 282 study participants were not on a previous regiment of supplements prior to the study; as such, the authors ended up only focusing their results on those forty-six percent, or 16, 718 women.

The women who were randomly selected to receive the calcium and vitamin D as part of the study procedure suffered a moderate thirteen to twenty-two percent amplified risk of cardiovascular problems, most especially heart attacks.

Participants in the placebo group underwent no change in risk.

Most post-menstrual women ingest calcium supplements with or without vitamin D in an effort to maintain bones health, which has been standard medical advice for a long time.

"Our own recommendation is to critically review the use of calcium supplements, since the data in this paper suggests that they do more harm than good," reported Reid, who is a professor of medicine and endocrinology at the University of Auckland in New Zealand.

"The cautious way forward seems to be to encourage people to obtain their calcium from the diet, rather than from supplements, since food calcium has not been shown to carry this increased risk of heart disease," Reid added.

Researchers were disappointed by the inconclusive data, as most had fully expected the results would have a "significant impact on recommendations” for post-menstrual women.

When researchers of this study combined their data with the results from thirteen separate unpublished trials, however, which all focused on the risk of calcium supplements to the heart, the percentage for heart attack went up to twenty-five to thirty percent, and for a stroke, fifteen to twenty percent; these trials put together included about 30,000 women.

Still, while these results are impressive and are certainly significant statistically, they are not necessarily going to have any clinical effect. Nevertheless, some professionals are taking the study to heart anyway and have begun doing as Reid suggested by advising their patients to get their calcium from their diet rather than supplements.

Dr. Susan V. Bukata, associate professor of orthopedic surgery at the University of Rochester Medical Center, is one such professional. While she agrees that the study results are inconclusively, she still encourages her patients to turn to food rather than vitamins, and stated "with diet plus a supplement combined, women should be getting 1,000 to 1,500 milligrams a day.”

Most professionals advise women to consult their physicians and use common sense when it comes to deciding whether they themselves need the supplements or not. "If women have good reason to take calcium because their bones are thin, then they should not be afraid of taking the calcium," said Dr. Philip Houck, assistant professor of internal medicine at Texas A& M Health Science Center College of Medicine.

The conclusion of the study states, “Calcium supplements with or without vitamin D modestly increase the risk of cardiovascular events….A reassessment of the role of calcium supplements in osteoporosis management is warranted.”

The study was released online on April 19th, 2011, in BMJ.