Calcium supplements no help for bones: NZ study


cottage cheese and milk

Calcium supplements have no benefit for most people and could even be harmful, claim University of Auckland researchers.

Two studies published in the British Medical Journal this week, conclude that increasing calcium intake is unlikely to improve bone health or prevent fractures in older people.

Therefore, increasing calcium intake through diet or supplements should not be recommended for fracture or osteoporosis prevention, says University of Auckland Associate Professor of Medicine, Dr Mark Bolland.

“Collectively, these results suggest that clinicians, advocacy organisations and health policymakers should not recommend increasing calcium intake for fracture prevention, either by use of calcium supplements or dietary sources,” says Dr Bolland.

“For most patients who are concerned about their bone health, they do not need to worry about their calcium intake.”

Current guidelines recommend that people should take 1000-1200mg per day of calcium to help improve bone density and prevent fractures or osteoporosis.

Recent concerns about the safety of calcium supplements have led experts to recommend increasing calcium intake through food rather than by taking supplements, but the effect on bone health was unknown.

The researchers led by Dr Bolland examined the evidence around increasing calcium in the diet, or supplement and its effects on bone health and fracture prevention.

They analysed the available evidence from randomised controlled trials and observational studies of extra dietary or supplemental calcium in women and men aged older than 50. Study design and quality were taken into account to minimise bias.

“In the first study, we found that increasing calcium intake from dietary sources or by taking supplements produces small (1-2%) increases in bone mineral density that are unlikely to lead to a clinically meaningful reduction in risk of fracture,” says Dr Bolland.

He adds the second study found that increasing calcium in the diet does not prevent fractures.

According to co-author, Professor Karl Michaëlsson from Uppsala University in Sweden, it’s time to revisit the recommendation about increasing calcium intake beyond a normal balanced diet.

He says that ever increasing intakes of calcium and vitamin D recommended by some guidelines defines virtually the whole population older than 50 at risk.

“Yet most will not benefit from increasing their intakes”, he says, “and will be exposed instead to a higher risk of adverse events [such as gastrointestinal side effects]”.

“The weight of evidence against such mass medication of older people is now compelling, and it is surely time to reconsider these controversial recommendations,” he says.

For more on the research click here.

Sue MacDonell, NZ Registered Dietitian and PhD Candidate, Department of Human Nutrition, University of Otago, says, “The Nutrient Reference Values for calcium in Australia and New Zealand were set to maintain calcium balance, that is, to ensure that the amount of calcium consumed is similar to the amount lost through excretion.

“There is some evidence that aging results in both a reduction in calcium absorption and an increase in calcium loss, hence the higher calcium requirements recommended for older men and women. These higher intakes are intended to minimise loss of calcium from bone stores.

“These most recent papers are clear in their recommendation that calcium supplements should not be prescribed to older adults on the basis of improving bone mineral density or preventing fractures.  It is important to remember, however, that besides contributing to bone health, calcium also has other roles in the body.

“For this reason it is important that the decision to prescribe calcium supplements is made based on the health needs of each person as any dietary supplement, including calcium, should only be prescribed if the person has a demonstrated need.

“Dietitians agree that it can certainly be difficult for older people to meet the higher recommendations for calcium solely from food, particularly if dairy products are not regularly consumed and consequently there are instances where calcium supplementation is indicated.

“In light of these most recent findings, physicians and dietitians should consider the appropriateness of calcium supplementation for each patient. Considerations include the amount of calcium being consumed from dietary sources, tolerance of the supplement and other health conditions such as cardiovascular risk.

“Furthermore it is worthwhile to check that very high amounts of calcium are not being consumed from all sources combined.”

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