"The authors characterize these findings as though all of the selected studies suggest increased risk. In fact, the opposite is true: most of the studies do not suggest increased risk," says Dr. Shao. "Bone health is one of the most common reasons why healthcare professionals recommend calcium supplements; there are other health benefits that may be associated with calcium supplementation, such as reduction of colon cancer risk. This is not even considered by the authors. It's unfortunate that these researchers are making sweeping judgments about the value of calcium supplements by only assessing a handful of handpicked studies."

Dr. Shao also pointed out that none of the original studies included in the meta-analysis were designed to evaluate cardiovascular outcomes. Additionally, the data on cardiovascular events was never previously published, so the meta-analysts had to track the information down separately, in some cases, 10 even 20 years after the original study was published.

"Meta-analysis can be a useful tool for scientific evaluation, but we have to recognize its limitations, and keep in mind that its findings are based on a collection of past studies that may have different designs, doses and study populations," says Dr. Shao. "This analysis should not dissuade consumers, particularly young women, from taking calcium supplements. They should talk with their doctors about their current and long-term needs and determine how much calcium they are getting from their diets, and supplement accordingly-likely in combination with vitamin D."

Source: Council for Responsible Nutrition