A new prospective cohort study published by the American Medical Association (JAMA Internal Medicine) disputed a long held belief that coffee increases the risk of abnormal heart rhythms known as arrhythmias. Doctors have long been advising people with a history of abnormal heart rhythms (especially fast heart rhythms) to avoid consuming coffee due to concerns that it may increase the risk of causing an abnormally fast heart rhythm (e.g. supraventricular tachycardia).
This new study assessed more than 300,000 participants and found that each additional daily cup of coffee is associated with a 3% reduced risk of developing an arrhythmia. The study also assessed genetic variations in caffeine metabolism amongst the study participants and found no significant group differences. Importantly, this study provides new evidence that habitual coffee consumption is associated with a lower risk of arrhythmia, and backs up evidence suggesting that coffee consumption is protective against heart disease.
Is drinking coffee safe?
While this study reveals new evidence suggesting coffee does not increase the risk of arrhythmia, those with a history of fast or abnormal heart rhythms should talk to their doctor before resuming a coffee binge. Why? Because this study was a population-based community study and did not assess people with existing cardiovascular disease.
For the most part, evidence suggests that drinking coffee is overall protective against heart disease as well as other forms of cardiovascular disease. However, the decision to drink coffee is an individual one, and will depend on the health status of the individual. Coffee is not recommended for people with an established history of tachyarrhythmia (fast abnormal heart rhythm), nor those with conditions such as peptic ulcer disease and gastritis, and is known to increase symptoms of anxiety in people suffering from anxiety disorders.
Previous evidence indicates coffee consumption reduces cardiovascular disease risk
A meta-analysis conducted in 2013 assessed 35 cohort studies involving 1,283,685 participants. This large study showed that moderate coffee consumption was associated with lower cardiovascular disease (CVD) risk, with the lowest CVD risk at 3 to 5 cups per day of coffee consumption. It also found that heavy coffee consumption was not associated with elevated CVD risk. This is despite heavy coffee drinking also being associated with less healthy lifestyles such as higher rates of cigarette smoking, lower rates of physical activity and less healthy diets; confounders which further support the idea that coffee consumption is protective.
References:
1. Kim et al. Jul 2021. Coffee consumption and incident tachyarrhythmias: reported behaviour, Mendelian randomization, and their interactions. JAMA Internal Medicine. Available from: https://jamanetwork.com/journals/
2. Ding et al. 2013. Long-term coffee consumption and risk of cardiovascular disease. Circulation. Available from: https://www.ahajournals.org/