London - Older people are unlikely to reduce their risk of breaking a bone by taking calcium supplements or upping their dietary intake, according to two new reviews, which challenge established medical guidelines.
Calcium, found in dairy products, vegetables and nuts, is vital for healthy teeth and bones. Healthy adults need about 700mg a day, which most of us get from our diet.
However, according to guidelines in the UK, older people at risk of bone fractures should take at least 1 000mg a day, and are often prescribed supplements.
The recommendation is based on calcium's ability to increase the density of bones. But two studies led by researchers at the University of Auckland in New Zealand, and published in the BMJ, say the effect is small and may not outweigh the risk of taking too much calcium, which has been linked to side effects such as constipation, stomach pain and an increased risk of cardiovascular problems.
In the first paper researchers found that increasing calcium intake in the diet or with supplements only increased bone mineral density by around one to two percent, which they said was unlikely to lead to “clinically meaningful” protection against fractures. The second concluded there is no evidence “that increasing dietary calcium intake prevents fractures”.
Evidence on supplements was stronger with the risk of fractures reduced by 11 percent, but researchers said that this may not be enough to outweigh the risks of taking too much calcium.
The Daily Mail reports that the team from the University of Auckland reviewed dozens of clinical trials for people aged over 50 related to fractures and bone density.
Professor Karl Michaelsson, of Uppsala University in Sweden, published research last year suggesting a high milk intake may not cut our risk of breaking a bone. He said that the “continued emphasis” on increasing calcium intake to prevent fractures was “puzzling”.
“The profitability of the global supplements industry probably plays its part, encouraged by opinion leaders from the academic and research communities,” he said. “Manufacturers have deep pockets, and there is a tendency for research efforts to follow the money, rather than a path defined only by the needs of patients and the public.”
The Independent