Calcium supplements increase your risk of having a heart attack, new research warns.
More than half of women aged 60 and above take the pills to keep their bones strong.
However, a 10-year study at Johns Hopkins University has concluded these boosters tend to drive up the levels of plaque buildup in the arteries - putting pressure on the heart.
As a result, their data showed, users were 22 per cent more likely to have a heart attack.
'When it comes to using vitamin and mineral supplements, particularly calcium supplements being taken for bone health, many Americans think that more is always better,' says Dr Erin Michos, associate director of preventive cardiology at the Ciccarone Center for the Prevention of Heart Disease at Johns Hopkins.
'But our study adds to the body of evidence that excess calcium in the form of supplements may harm the heart and vascular system.'
The researchers studied 2,700 - aged 45 to 84 - who completed dietary questionnaires and two CT scans spanning 10 years apart.
Studies already showed that ingested calcium supplements - particularly in older people - don't make it to the skeleton or get completely excreted in the urine.
The new study focused on where they do end up, suspecting that they must be accumulating in the body's soft tissues.
Starting in 2000, all participants answered a 120-part questionnaire about their dietary habits to determine how much calcium they took in naturally.
Calcium can be found in dairy products, leafy greens, and cereals, among other foods.
Separately, the researchers asked what drugs and supplements each participant took on a daily basis.
The investigators used cardiac CT scans to measure participants' coronary artery calcium scores, a measure of calcification in the heart's arteries and a marker of heart disease risk when the score is above zero.
Initially, 1,175 participants showed plaque in their heart arteries.
The coronary artery calcium tests were repeated 10 years later to assess newly developing or worsening coronary heart disease.
For the analysis, the researchers first split the participants into five groups based on their total calcium intake, including both calcium supplements and dietary calcium.
The researchers separated out 20 per cent of participants with the highest total calcium intake, which was greater than 1,400 milligrams of calcium a day.
That group was found to be on average 27 per cent less likely than the 20 per cent of participants with the lowest calcium intake - less than 400 milligrams of daily calcium - to develop heart disease, as indicated by their coronary artery calcium test.
Next, the investigators focused on the differences among those taking in only dietary calcium and those using calcium supplements.
Forty-six per cent of their study population used calcium supplements.
The researchers found that supplement users showed a 22 per cent increased likelihood of having their coronary artery calcium scores rise higher than zero over the decade, indicating development of heart disease.
'There is clearly something different in how the body uses and responds to supplements versus intake through diet that makes it riskier,' says Anderson.
'It could be that supplements contain calcium salts, or it could be from taking a large dose all at once that the body is unable to process.'
Among participants with highest dietary intake of calcium - over 1,022 milligrams per day - there was no increase in relative risk of developing heart disease over the 10-year study period.
'Based on this evidence, we can tell our patients that there doesn't seem to be any harm in eating a heart-healthy diet that includes calcium-rich foods, and it may even be beneficial for the heart,' says Michos.
'But patients should really discuss any plan to take calcium supplements with their doctor to sort out a proper dosage or whether they even need them.'
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— Last Edited by Greentea at 2016-10-13 10:09:23 —