The study looked at diet records of 24,000 people in Germany aged 35 to 64 and claim the safety of calcium tablets is 'coming under increasing scrutiny'
Taking calcium supplements can push up the risk of a heart attack, warn researchers.
They claim the safety of the tablets is 'coming under increasing scrutiny' as they could be doing more harm than good.
Hundreds of thousands of women take the boosters as they are recommended for strengthening bones against osteoporosis.
But, according to the study, the supplements can no longer be seen as a low-cost panacea against thinning bones.
Instead, the scientists suggest, people should eat more calcium-rich foods like milk, cheese and green, leafy vegetables.
They found that those using calcium boosters, with no other supplements, had double the risk of a cardiac attack than others who did not take them.
Researchers looked at records for 24,000 people in Germany aged 35 to 64 taking part in a nutrition research project in the 1990s.
Their diet was analysed and they were asked if they had taken vitamin or mineral supplements in the previous month.
Experts warn the safety of the tablets is 'coming under increasing scrutiny' as they could be doing more harm than good
Eating cheese and other calcium rich dairy products is a better way of getting the nutrient than supplement pills, researchers say
MEN'S JUNK FOOD SECRET
The volunteers were tracked for 11 years, during which there were 354 heart attacks, 260 strokes and 267 associated deaths.
Those taking any supplements, including calcium, were found to be 86 per cent more likely to have a heart attack than those who did not take any. But the risk for those taking only calcium was even higher.
Researchers claim the tablets have a potentially harmful 'flooding' effect on the levels of the mineral in the blood, it was reported in the medical journal Heart. Calcium in food or drink is spread through the day and so absorbed slowly.
In the study, Professors Ian Reid and Mark Bolland, at the University of Auckland, New Zealand, said people should be discouraged from taking the boosters.
It was also wrong to see them as natural as they do 'not reproduce the same effects as calcium in food', they added.
The National Osteoporosis Society said there was not enough evidence to say the supplements trigger heart problems.
The Food Standards Agency advises adults to have 700mg of calcium a day in their diet.
Read more: http://www.dailymail.co.uk/news/article-2149031/Calcium-booster-pills-raise-risk-heart-attack-harm-good.html#ixzz1voHIw2Lb