Skip to content


Calcium may increase heart attack risk (but only just)

Calcium may increase risk of heart attackOoh, I love a good ‘vitamins may kill you’ story (though they don’t exactly make ideal reading for riskfactorphobes). Why do I love them? Because, in the vast majority of cases, when you look beyond the sensationalist headlines and work out what the story’s really about, the ‘vitamins kill you’ aspect turns out to be a load of old nonsense.

And this latest calcium supplements increases heart attack risk story is no exception.

So what’s it all about then? Well, if you’ve just read the headlines you’ve probably already binned your calcium supplements. If you haven’t, however, hang on a minute. Let me explain.

The widely-reported story concerns a study published in the British Medical Journal, which suggests that taking calcium tablets is linked with a 30 percent increased risk of heart attack. As explained by the National Osteoporosis Society, this may be a result of calcium slowly building up in the blood vessels (or calcification of the blood vessels). Why has the NOS chipped in? Because calcium supplements are widely taken by people who have an increased risk of developing osteoporosis (brittle bones).

Hmm, a 30 percent increased risk – that means whatever your risk was in the first place, by taking calcium tablets you could be increasing that risk factor by 30 percent. I don’t have the figures to hand, but I have just listened to an interview with Professor John Cleland, a cardiologist at Hull University, who does. Speaking on  BBC Radio 4 to the Today programme presenter, Evan Davis, Professor Cleland – who I trust has done his homework, therefore the statistics he states are correct – explains that the 30 percent increase is a relative increase of what’s a rather small risk in the first place. “In terms of an absolute increase in risk we’re talking about one or two percent,” he explains.

Yes, I repeat, ONE or TWO percent.

As Professor Cleland explains, that means for 100 people taking calcium supplements, just one or two of them is more likely to develop a heart attack than someone who doesn’t take extra calcium. “So we shouldn’t be too scared about this 30 percent relative increase,” he adds.

Too right, one or two people in 100 – that means 98-99 people out of 100 taking calcium supplements are not likely to have a heart attack. While it’s obviously not good news if you’re one of those one or two people, you’ve got to admit, the odds against it happening are pretty well stacked in your favour.

Not just that, but the heart attacks in the study weren’t fatal heart attacks – there was, apparently a trend towards an increase in mortality, but according to Professor Cleland, it wasn’t significant. In fact, he goes on to say that some of the heart attacks in question may not have been heart attacks at all – but diagnoses of heart attacks that could feasibly have been something else.

So have you fished your bottle of calcium tablets out of the bin yet? Wait, there’s more. The really interesting finding from the study, says Professor Cleland, is that the taking of calcium supplements was found to have a pretty poor effect on the incidence of fractures. Interestingly, taking calcium supplements were found to have an effect on bone mineral density (that is, they strengthen bones), but they didn’t stop people breaking them – which doesn’t particularly make sense, but hey, that’s medical research for you.

So maybe it’s not worth taking the supplements after all. But if you do (and there are many reasons why people take calcium tablets), it’s highly unlikely you’ll have a heart attack because of them (at least, that’s going by what this study really says).

But don’t take my word for it. Listen to what Professor Cleland says (click on the link above to hear his interview).

Posted in Food and drink, General health.

Tagged with , , , , .


One Response

Stay in touch with the conversation, subscribe to the RSS feed for comments on this post.

Continuing the Discussion

  1. Calcium supplements: the backlash begins – riskfactorphobes anonymous linked to this post on August 6, 2010

    [...] last week I wrote about the ‘Calcium increases your risk of heart attack’ story (see Calcium may increase heart attack risk, but only just…). Now the backlash to the story has started, and first on the scene is the US-based National [...]