BY THE OPTIMIST DAILY EDITORIAL TEAM
Conventional wisdom has long warned people with heart rhythm disorders to steer clear of caffeine. But a world-first clinical trial suggests that advice may need an update. Researchers from the University of Adelaide and the University of California, San Francisco (UCSF) found that drinking at least one cup of coffee a day may actually protect against atrial fibrillation (AF), a common irregular heartbeat linked to stroke and heart failure.
Their findings, described by the team as “astounding,” challenge decades of caution around caffeine. As first author Professor Christopher X. Wong explained, the coffee drinkers “experienced a significant reduction in AF compared to those who avoided coffee and caffeine,” a result that went “against the common assumption by doctors and patients that coffee worsens heart rhythm disorders.”
What the DECAF trial uncovered
The DECAF (Does Eliminating Coffee Avoid Fibrillation) trial followed 200 adults with AF from Australia, the United States, and Canada over six months. Half the participants consumed at least one caffeinated coffee or espresso shot daily, while the other half abstained entirely. Continuous monitoring, electrocardiograms, and clinician evaluations confirmed every AF episode.
The contrast between the groups was striking. Participants who drank coffee had a thirty‑nine percent lower risk of recurrent AF events. For a condition that affects more than ten million adults in the United States alone, that reduction could be meaningful.
Senior author Professor Gregory Marcus from UCSF offered several possible explanations. “Coffee increases physical activity which is known to reduce AF,” he said. He added that caffeine’s diuretic effects may help lower blood pressure, and that coffee contains anti-inflammatory compounds that may offer additional protection.
Rethinking long-standing advice
For years, AF patients have been told to limit or eliminate caffeine, often out of an abundance of caution. But this study suggests the relationship isn’t so straightforward. Wong noted that the trial indicates coffee is “not only safe but likely to be protective,” and Marcus emphasized that the findings “should change the medical advice we give to patients.”
Still, experts stress that coffee is not a cure-all. AF can arise from a wide range of causes, including obesity, sleep apnea, diabetes, and family history. Lifestyle choices remain a major factor. But revisiting outdated assumptions may give patients more freedom and fewer unnecessary restrictions.
Why this matters for millions of coffee drinkers
Around two-thirds of adults in the United States drink at least one cup of coffee daily. Scientists have long explored its links to healthy aging, brain function, and cardiovascular health. With AF cases expected to rise as the population ages, the need for clarity has only grown more urgent.
Marcus noted that interest in preventing AF is high because “the risk of developing the condition increases with age.” These new findings point toward a simple, accessible option for many people living with the condition.
While the researchers don’t suggest that everyone with AF must start brewing immediately, the takeaway is reassuring: coffee does not need to be blacklisted. As Wong put it, “Based on these results, coffee-drinking patients with AF can safely continue to enjoy their coffee,” adding that it might even be worth exploring whether non-drinkers could benefit from incorporating a daily cup.
