Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.
Why is this research important: There is a common notion that too much caffeine is bad for your heart. Based on what scientists know of the mechanisms of action of caffeine within the body, it has been speculated that caffeine might increase the risk of cardiac arrhythmia (an abnormal heart rhythm). Caffeine overdoses certainly have the potential to trigger lethal arrhythmias, though for most people this would require the acute consumption of around 10 grams of caffeine, which is equivalent to drinking 50 to 100 cups of coffee in rapid succession.
Many believe that habitual consumption of caffeinated products like coffee can increase the risk of developing a cardiac arrhythmia. However, this idea is not currently well supported by evidence.
What did the researchers do: In this study, researchers analysed data from 386 258 participants from the UK Biobank – a follow up study of 500 000 volunteers enrolled between the ages of 40 and 69. They investigated whether there was any association between coffee consumption and the incidence of cardiac arrhythmias after adjustment for demographic factors, comorbidities and lifestyle habits. They also examined whether the relationship was affected by genetic variants associated with slower caffeine metabolism.
Key takeaway(s) from this research: Researchers found no significant association between coffee consumption and increased risk of arrhythmia, even in those with genetic variants associated with slower caffeine metabolism. Indeed, each additional cup of coffee consumed was associated with a statistically significant reduction in arrhythmia incidence of around 3%, suggesting that coffee consumption may actually be beneficial in this regard.
This effect may be due to the beneficial effects of compounds found within coffee other than caffeine. For example, coffee contains anti-inflammatory compounds, and inflammation is associated with increased risk of arrhythmias. There are also ways in which caffeine itself might protect against arrhythmia at low doses. For example, caffeine interacts with the sympathetic nervous system by blocking adenosine receptors. Although this contributes to causing arrhythmias at toxic caffeine doses, overactivation of adenosine receptors can also trigger arrhythmias, and so some amount of receptor blockage by lower doses of caffeine may be beneficial.
The potential benefits of coffee for reducing the risk of arrhythmia requires further investigation, but this study does add to a growing body of evidence suggesting that habitual coffee consumption does not increase the risk of arrhythmias as is commonly believed. Cutting down on coffee intake to reduce the risk of arrhythmia may do more harm than good due to the many emerging benefits of regular coffee consumption.
Coffee Consumption and Incident Tachyarrhythmias Reported Behavior, Mendelian Randomization, and Their Interactions: http://jamanetwork.com/article.aspx?doi=10.1001/jamainternmed.2021.3616
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