CAUTION HAS been urged by the Irish Osteoporosis Society on a study which found that calcium supplements may increase the risk of heart attack by as much as 30 percent.
Prof Moira O’Brien, president of the Irish Osteoporosis Society, said that the study only looked at cases where calcium was taken without vitamin D.
Calcium should not be taken on its own but with vitamin D supplements to help people absorb it, she said.
The results of the study by researchers in New Zealand, Britain and the United States were published in the British Medical Journalyesterday.
They conducted a meta-analysis encompassing 11 studies that tracked nearly 12,000 elderly people over four years.
Half of them were given calcium supplements and the other half placebo or dummy pills with no therapeutic content.
“If you have 1,000 people taking calcium for five years, we will expect to find 14 more heart attacks, 10 more strokes and 13 more deaths in the people given calcium than they would have had if they had not been treated with calcium,” Ian Reid, professor of medicine at the University of Auckland, said.
While calcium supplements would prevent 26 more fractures, it would cause 36 more adverse affects.
If people taking calcium have low vitamin D levels they don’t absorb calcium, Prof O’Brien said on RTÉ radio. This increases activity in the parathyroid gland which can increase osteoporosis and other conditions, she added.
Calcium supplements are prescribed to reduce the risk of fractures and to prevent and treat osteoporosis, a thinning of the bones.
Previous studies had found no increased risk of heart attacks with higher calcium intake from food. The analysis suggests that the extra hazard is associated with supplements, the medical journal said in a statement.
