A new study in the British Medical Journal claims that calcium supplements increase the risk of heart attacks and strokes. But natural products industry experts criticized the research methodology and findings.
In the meta-analysis, Ian Reid, PhD, from the University of Auckland in New Zealand, and other researchers used the Women’s Health Initiative Calcium/Vitamin D Supplementation Study dataset—a seven-year trial including 36,282 postmenopausal women—to evaluate how calcium supplements affect cardiovascular risk. They concluded that calcium supplements with or without vitamin D "modestly increase the risk of cardiovascular events," and they called for reevaluating whether calcium supplement should be recommended for osteoporosis management.
Cara Welch, PhD, vice president of scientific and regulatory affairs for the Washington, D.C.-based Natural Products Association, pointed out problems with the research. "We saw this same flawed analysis last year with some slight changes, but we’re still looking at a meta-analysis of other studies," Welch said in a release. "The eight studies that were included last time weren’t originally set up to look at cardiovascular events, and the Women’s Health Initiative Calcium/Vitamin D Supplementation Study reported ‘no adverse effect of calcium and vitamin D … on any cardiovascular end point.’"
John Hathcock, senior vice president of scientific and international affairs for the Washington, D.C.-based Council for Responsible Nutrition, said the findings were more likely "a statistical methodology effect, rather than a true health effect," and study authors seemed to pick and choose findings to make a case against calcium supplementation. "The authors elected to discuss in the text of the reanalysis those outcomes which would be most contrary to use of supplemental calcium, but barely identified possible beneficial effects," Hathcock said. "For example, while the authors did include data for those who before the trial had 'any personal use of calcium' having a highly significant 16 percent decrease from death from all causes, they chose to ignore that point in their text, having identified it only in a table."
Should you take calcium?
Last summer, calcium came under similar fire for its link to increased heart attack risk, and, at the time, natural products industry associations criticized that study as well. CRN said in a statement that the conclusions of the 2010 meta-analysis published in the British Medical Journal were "overstated." The NPA called the study "less than satisfactory." Daniel Fabricant, then vice president of global government and scientific affairs for NPA, didn't think the study provided enough evidence to warrant eliminating calcium supplements.
Despite the new published findings against calcium supplements, Welch still doesn't think consumers should doubt the value of calcium supplementation. She said many studies tout the benefits of calcium and vitamin D, which helps people properly absorb calcium. If you take calcium, there's no reason to stop, according to Welch. “We have seen over and over the argument that Americans can get all the nutrients they need from a balanced diet. But the fact is, most don’t," Welch said. "We hope that all individuals who use calcium supplements for bone health, and especially those under the direction of a physician, will continue their supplementation and not be swayed by this flawed analysis.”