By medical reporter Sophie Scott
Updated Tue Aug 3, 2010 4:33pm AEST
One of Australia's leading health experts has cast doubt on new research suggesting calcium supplements may increase the risk of heart attacks.
Professor Chris Nordin from the Royal Adelaide Hospital has been working on calcium metabolism and osteoporosis for more than 50 years. He drafted the World Health Organisation dietary calcium recommendations, which have been adopted in Australia.
He queries the findings of a recent review into calcium and heart attack risk published recently in the British Medical Journal.
Professor Ian Reid from the Department of Medicine at the University of Auckland reviewed 11 studies of almost 12,000 people.
His review found calcium supplements were associated with an increased risk of heart attack of about 30 per cent and smaller, non-significant increases in the risk of stroke and mortality. The findings were consistent across trials and were independent of age, sex and type of supplement.
But Professor Nordin says the review is misleading because it includes studies involving a mixture of men and women.
"Men are much more liable to heart attacks than women but women need calcium far more than men, so it is absurd to publish a study of the effect of calcium on the heart without separating men from women," he said.
Professor Nordin says calcium supplements are predominantly recommended for and used by postmenopausal women because their bone loss is due to an increase in bone breakdown, which responds to calcium (with vitamin D if necessary). But they are seldom recommended for elderly men because their bone loss has a different cause, which seldom needs calcium.
He says the findings were not statistically significant.
"Concluding that calcium supplements can lead to a 30 per cent increase in heart attack risk is quite premature and alarmist and can only set back the cause of osteoporosis prevention which should be our primary objective," he said.
Osteoporosis Australia has also queried the findings of the review, saying many long-term studies have shown calcium supplements are safe and effective.
In a statement on its website, Osteoporosis Australia says the weight of evidence to date indicates no increased risk of heart attacks from taking calcium supplements.
Osteoporosis Australia says calcium supplements are an effective way of reducing fracture risk and bone loss in older men and women who have a diet low in calcium.
Professor Nordin says he would like to see all women have their bone density measured at menopause so that women with low to normal bone density can take dietary and exercise measures to prevent osteoporosis developing.
As for calcium supplements, as the doctor responsible for setting current daily recommendations, he says 1,300mg for post-menopausal women is appropriate and could even be set a little higher. , osteoporosis, australia