Higher intake of dietary calcium could reduce risk of fractures, study suggests

Researchers are challenging the long-held belief that consuming more calcium from food or supplements lowers the risk of fractures. Two new studies from New Zealand present latest evidence that reveal extra calcium intake may not yield health benefits, and could instead lead to a higher risk of gastrointestinal symptoms and kidney stones.

The studies, published in the British Medical Journal, examined the effects of calcium intake on bone density and risk of fracture in adults over age 50. Study author Mark Bolland, associate professor at the University of Auckland’s Department of Medicine, and his colleagues say calcium may not necessarily improve bone health as some medical experts claim.

According to the researchers, many older individuals turn to calcium supplements to meet dietary recommendations, since the average daily calcium intake among older adults in Western countries is only around 700 to 900 milligrams.

However, in the first report, researchers found that increasing calcium intake, either through diet or by taking supplements, only increased a participant’s bone-mineral density by up to two percent. The team had employed a meta-analysis to study the results of 59 previous randomised controlled trials of calcium, which involved more than 12,000 participants.

The two percent increase was not enough to meaningfully reduce a person’s risk of fracture, the researchers claim.

The team also reviewed more than 40 studies of people’s diets for their second analysis. Based on the data gathered, they found no association between the amount of calcium people consumed and their risk of bone fracture. In further studies involving 26 randomised controlled trials of calcium supplements, the scientists noted a slight reduction in people’s fracture risk with calcium supplements, but concluded that the evidence was weak and inconsistent.

The findings of Bolland and his team support previous studies that debunk claims by health experts about the benefits of calcium. In a 2013 report from the U.S. Preventive Services Task Force, the authors concluded that there is no evidence showing the mineral, along with vitamin D, reduced the risk of fracture in healthy, postmenopausal women.

In an editorial that accompanied the new Auckland University studies, Professor Karl Michaëlsson of the Department of Surgical Sciences at Uppsala University in Sweden noted that the latest research corroborates with a study published 25 years ago, claiming that calcium supplements to prevent fractures were not justified by the available evidence. He also cautioned people of the health risks associated with consuming more calcium.

“Most will not benefit from increasing their [calcium] intakes and will be exposed instead to a higher risk of adverse events such as constipation, cardiovascular events, kidney stones or admission for acute gastrointestinal symptoms,” he says.

Given that the weight of evidence against the mass medication of older people is now compelling, Michaëlsson says it is time to reconsider recommendations on calcium intake.

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