Calcium supplements increase heart attack risk by 86%, study finds
Patients at risk of osteoporosis should be encouraged to alter their diet rather than rely on calcium supplements, say researchers after a new study found they increased the risk of a heart attack by 86%, compared with those not taking supplements.
Patients at risk of osteoporosis should alter their diet rather than rely on calcium supplements, say researchers after a new study found they increased the risk of a heart attack by 86%, compared with those not taking supplements.
The large study of 24,000 people showed patients who had a high level of dietary calcium lowered their risk of a heart attack by a third, when compared with those with lower levels of calcium intake.
The evidence adds to previous studies casting doubt on NICE guidance that GPs should consider calcium supplements in all postmenopausal women at risk of osteoporosis.
MHRA said it was ‘carefully evaluating' the new data, and experts said it reinforced that GPs should look at optimising patients' lifestyle, before resorting to supplementation.
The study by German and Swiss researchers looked at men and women aged between 35- 64 years, with no history of cardiovascular problems, and followed them for 11 years.
They found those taking vitamin and mineral supplements which included calcium had an 86% increased risk of a heart attack compared with those who didn't take supplements.
The risk increased to 139% for those taking calcium-only supplements compared with those taking no supplements at all, they found.
They also found increasing dietary calcium intake reduced the risk of heart attacks. Those in the third quartile of calcium intake had a 30% lower risk of heart attacks than the first quartile, with the results statistically significant for women - who are more likely to take calcium supplements to prevent osteoporosis - than men.
No statistically significant association was found between taking calcium supplements, increasing dietary intake of calcium and the risk of strokes and CVD mortality.
The study's lead author Professor Kuanrong Li, lead researcher in cancer epidemiology at the German Cancer Research Centre, Germany, said: ‘Total, dairy, or non-dairy calcium intake did not have an overall statistically significant inverse association with cardiovascular risk, except for a likely reduction of myocardial infarction risk associated with a moderately higher calcium intake.'
‘Calcium supplement, which might raise myocardial infarction risk, should be taken with caution.'
In an editorial, Professor Ian Reid and Professor Mark Bolland, deputy dean and senior research fellow respectively at the Faculty of Medical Sciences, University of Auckland, said the study showed supplementation was ‘not natural'.
They said: ‘We should return to seeing calcium as an important component of a balanced diet and not as a low-cost panacea to the universal problem of postmenopausal bone loss.'
Dr Christopher Arden, a GPSI in cardiology in Eastleigh, said the study's results were ‘very interesting' and showed regular exercise and a balanced diet may be more beneficial than supplements: ‘The bottom line is that as GPs we have to look at approaches optimising lifestyles,' he said.
A spokesperson for the MHRA said they would ‘carefully evaluate' the new study: ‘We will provide updated advice if necessary.'