Calcium supplements ‘double risk of heart attack’, study finds

Doctors dispute results but advise people not to take supplements unless required for medical condition

Calcium supplements can almost double the risk of a heart attack, according to new research, and should be “taken with caution” and only for medical reasons, such as to prevent bone thinning. The study contradicts the commonly held belief that consuming extra calcium can help prevent heart disease or a stroke.

The findings are based on a study of the calcium intake of 23,980 men and women in Heidelberg, Germany, who were aged 35-64 when they joined a local cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) study in 1994-98. Researchers checked participants’ health for 11 years afterwards, during which time 354 of them had a heart attack and 260 a stroke and there were 267 associated deaths. They also tracked how much calcium they consumed from any source.

They found that people who used calcium supplements regularly were 86% more likely to suffer a heart attack than those who did not.

This constituted “a statistically significantly increased myocardial infarction [heart attack] risk in comparison with non-users of any supplements”, say the four co-authors led by Professor Sabine Rohrmann, from Zurich University’s institute of social and preventative medicine.

Those who obtained their calcium exclusively from supplements were 2.7 times more likely than non-users to experience a heart attack, they say in their research paper, published in the medical journal Heart.

“Increasing calcium intake from diet might not confer significant cardiovascular benefits, while calcium supplements, which might raise MI risk, should be taken with caution,” they conclude.


9 responses to “Calcium supplements ‘double risk of heart attack’, study finds

  1. Ben of Houston

    At least it’s a viable risk ratio this time, but I still suspect reverse causality on this (ie: Supplements don’t make you sick. Sick people take supplements)

  2. And then there is the question of baseline intake. Most of our drinking water is hyper-saturated with calcium.

  3. Roughly 1.5% of the study participants experienced one of these events. The calcium supplements may affect people who are sensitive in some way; the overall risk, even with the supplement, seems to remain very low for the co-hort.
    The usual next question — I didn’t follow to the study — is to see if the risk factor associates with dosage, e.g. 25mg Ca associates with 40% increased risk, 50mg with 84%, 150 with 100% increase, etc. When the risk factor tracks with the variable, you get a much more meaningful correlation.
    Most people who eat a reasonable diet are already getting all the trace elements they can really use. I think supplements generally should go with a recognized need for the individual.

  4. It wuld be interesting to see if they also tracked magnesum intake. If you take calcium you have to also take magnesium to balance it off. The same as sodium and potassium

  5. Geoff, it is not entirely correct to group calcium with trace elements. We’re talking about a kilogram or more in a human body. You get hundreds of milligrams per litter of calcium from tap water, unless you are fortunate enough to live in Scotland, where tap water is close to distilled.

    Whenever there is a case of calcium deficiency, the ultimate cause of it is a metabolic disorder of some sort (of which there can be plenty). It is hard to imagine that being a dietary problem. There is almost always a surplus of calcium on the uptake; calcium deficiency needs to be treated with drugs, not supplements. The most useful effect you can expect from a calcium supplement will be the absence of harm.

  6. This is deja-vu. A few decades ago, they went on an anti-calcium fad and those who bought into their scare ended up with severe osteoporosis. At that time it was blamed for plaque in the arteries, that was before they discovered cholesterol. It was also tied to the anti-milk scare where children were advise to eat brocolli for their calcium instead of drinking milk. In order for a child to get enough calcium from brocolli they would have to eat a pickup load of it every day. Very practical!

  7. This shows the lack of serious and honest research. Instead of tackling a problem, they dredge up some old disproven scare from the landfill of history, brush it off and run with it. They do this regularly with sodium.

  8. Quite true. Sodium is a regulated “contaminant” in water supply, while calcium is not. It’s good for your health, right?

  9. Additionally, I need a from/to in published results.
    “Doubles the risk” is hype, not useful information.

    For example, if “improved behavior” changes the chances of a negative event from “highly unlikely” to “very unlikely,” it could double/triple the risk, and still be of no interest to me, or pretty much anyone else.

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