Can too much coffee lead to early death?

News articles about coffee risks

Coffee is, for many people, essential to coaxing the brain’s cogs into action each morning. Now scientists have linked high levels of coffee consumption to higher mortality rates.

- The Times, 16 August 2013

This research was covered widely, including in The Independent, The Herald, The Telegraph, The Guardian and the Daily Mail, which said: “If you’re already holding your first coffee of the morning, you might want to put it down.”

There have been many studies looking at the effects of coffee drinking on death rates, which have produced conflicting findings. Several studies have linked drinking large amounts of coffee to higher death rates from cardiovascular disease or higher death rates generally, but others have found the reverse.

This American study, published in Mayo Clinic Proceedings, looked at 43,727 people – a large number – and excluded those who already had heart disease, stroke or cancer.

They found an association between drinking more than 28 cups of coffee a week and total death rates, but only in the under-55s. The results were adjusted for other factors that may affect them, such as smoking, weight and physical activity. But the authors admit that there may still be factors that have muddied the results.

There is a lot of confusion when it comes to the effect of coffee on heart health

One weakness of the study is that it only looked at coffee-drinking habits at one point in time. Participants were then followed up for an average of 17 years, during which their habits may have changed, although the study authors say “coffee drinking tends to be stable in adulthood”.

People weren’t asked how their coffee was prepared, so we don’t know whether they added sugar, milk or cream, for example, or if they made their coffee at home or bought it in coffee shops.

It’s not clear why coffee might have caused these effects, if indeed it did. As the study authors put it: “Coffee is a complex mixture of chemicals consisting of thousands of components.”

Our Heart Health Dietitian, Tracy Parker, said: “There is a lot of confusion when it comes to the effect of coffee on heart health. While some worry that caffeine may be bad for their heart, others hail its benefits.

“The research showed no link between death from cardiovascular disease and coffee drinking and it doesn’t change the current recommendations, which maintain that four or five cups of coffee a day won’t damage your heart.

“However, it’s important to remember that a cup is classed as a traditional teacup – a regular coffee on the high street can be twice as much.”

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