A study called DECAF found that drinking coffee may help AFib and was the first randomized controlled trial to investigate the relationship between caffeine and atrial fibrillation.Jose Luis Gutierrez/Getty Images/iStockphoto
If you live with persistent irregular heartbeats – called atrial fibrillation – you’ve likely been told to limit or avoid coffee for fear that caffeine can trigger symptoms.
Now, a new study challenges that longstanding advice.
Findings from the landmark clinical trial suggest that coffee may not only be safe, but also beneficial for AFib, as atrial fibrillation is also known.
Here’s a breakdown of the research, plus other lifestyle approaches to help manage the condition.
What is atrial fibrillation?
Atrial fibrillation is the most common type of irregular heart rhythm disorder, also known as arrhythmia. It occurs when electrical signals that guide the heart’s upper chambers, called the atria, become disturbed.
This causes fast, uneven contractions of the atria, resulting in blood not pumping completely through the heart. Reduced blood flow can increase the risk of a clot forming in the organ.
Symptoms of AFib can include shortness of breath, dizziness and fatigue. AFib can also cause people to feel their heart fluttering, racing or pounding in their chest.
Some people with AFib, however, don’t notice any symptoms and are unaware they have it.
Risk factors include older age, high blood pressure, coronary heart disease, heart valve problems and diabetes. The condition can also occur without an underlying cause; this is known as idiopathic or lone AFib.
If not treated and monitored, atrial fibrillation can lead to stroke and heart failure.
About the DECAF study
The new study, called DECAF (Does Eliminating Coffee Avoid Fibrillation?), was published Nov. 9 in the Journal of the American Medical Association. It is the first randomized controlled trial to investigate the relationship between caffeine and atrial fibrillation.
Researchers enrolled 200 patients who regularly drank coffee from hospitals in the U.S., Canada and Australia. The participants had either persistent AFib (episodes that last longer than seven days) or atrial flutter with a history of AFib. (Atrial flutter is caused by fast electrical signals to the heart, but the signals occur in a more organized pattern compared with atrial fibrillation.)
As well, they had all had undergone a successful cardioversion, a medical procedure that uses electric shock to restore normal heart rhythm.
The participants were assigned to either drink at least one cup of caffeinated coffee each day or to completely abstain from coffee, including decaffeinated versions, and caffeine-containing products such as tea, chocolate, soft drinks and energy drinks.
Researchers followed up with participants at one, three and six months during the study to assess coffee/caffeine intake and recurrence of AFib or atrial flutter.
After six months, participants who drank one cup of caffeinated coffee a day had a 39-per-cent lower risk of recurring AFib or atrial flutter episodes compared with those who avoided coffee and caffeine.
Study caveats
The sample size was modest, although similar to other trials on lifestyle factors and AFib.
Also, adherence in the abstinence group wasn’t perfect, with only 69 per cent avoiding coffee.
Participants in the coffee group had a moderate intake; the potential benefits observed can’t be generalized to heavy coffee consumption.
Findings in line with previous research
A randomized controlled trial published in 2023 found that, compared with the avoidance of caffeine, consuming caffeinated coffee did not cause more premature atrial contractions, which are known to trigger AFib.
Observational studies have generally reported no increased risk – and sometimes even a reduced risk – of AFib among regular coffee consumers.
The 2023 atrial fibrillation guidelines from the American College of Cardiology and the American Heart Association state that abstaining from caffeine to prevent AFib is of no benefit. It may, however, reduce AFib symptoms in people who report caffeine worsens their symptoms.
Individualized advice around caffeine consumption is still important.
How coffee may benefit AFib
Caffeine has been shown to block the action of adenosine, a chemical in heart cells that can provoke AFIb.
Chronic inflammation is a risk factor for AFib, and many phytochemicals in coffee have anti-inflammatory properties.
Caffeine is also a mild diuretic, potentially reducing blood pressure and AFib risk.
What about diet?
There’s no specific diet for AFib, but research suggests a Mediterranean diet enriched with extra-virgin olive oil (at least four tablespoons a day) can help some people.
The PREDIMAR randomized controlled trial, published in 2024, looked at whether following such a diet reduced AFib recurrence in patients who had undergone catheter ablation to treat the condition. (The procedure uses energy to destroy a small area of heart tissue that’s causing irregular heart heartbeats.)
It found that among 431 patients with paroxysmal AFib (temporary AFib episodes), the diet was tied to a significant reduction in recurrence compared with the control group. AFib relapses typically occur in up to 30 per cent of people after catheter ablation.
Lifestyle approaches to help manage AFib
For individuals who are overweight or living with obesity, a weight loss of at least 10 per cent is recommended to reduce AFib symptoms and recurrence, as well as to help prevent paroxysmal AFib from progressing to persistent AFib.
Moderate-to-vigorous exercise, working up to a target of 210 minutes a week, is also recommended to reduce symptoms and increase the maintenance of normal heart rhythm.
Alcohol consumption should be minimized or eliminated to reduce AFib recurrence.
Leslie Beck, a Toronto-based private practice dietitian, is clinical director of food and nutrition at Medcan.