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Drinking multiple cups of coffee each day may help prevent cognitive decline in people with a common type of heart rhythm disorder, new research suggests.

The , recently published in the Journal of the ·¬ÇÑÊÓƵ, adds to a body of research dispelling the belief that people with irregular heart rhythms such as atrial fibrillation, or AFib, should be discouraged from drinking caffeinated beverages, the authors said.

"Many myths are around, but our study found no reason to discourage or forbid a patient with AFib from drinking coffee," senior study author Dr. Jürg H. Beer said in a . Beer is a professor of medicine and hematology at the University of Zurich in Switzerland. "Instead, say, 'Enjoy, it may even be good for you!'"

AFib affects more than 5 million people in the U.S. and is the most common type of heart rhythm disorder in adults. People with AFib face a higher risk for cognitive decline, stroke and dementia.

Many health professionals have discouraged people with AFib from drinking caffeinated beverages. But in recent years, researchers have found little evidence to support this advice.

, released jointly in 2023 by the ·¬ÇÑÊÓƵ, American College of Cardiology, American College of Clinical Pharmacy and the Heart Rhythm Society, reported no benefit from avoiding coffee to prevent abnormal heart rhythms in people with AFib. However, the guidelines note that abstaining from coffee could reduce symptoms in people for whom caffeine triggers or worsens symptoms such as dizziness and fatigue.

Other studies have shown drinking coffee helps cognition in otherwise healthy people.

"The most frequent cardiac arrhythmia, atrial fibrillation, is known to independently increase the risk of dementia," lead study author Dr. Massimo Barbagallo said in the release. He is a resident in the neuro intensive care unit at the University Hospital Zurich. "Thus, the question is whether coffee might offset the increased risk of cognitive impairment in people with AFib."

Federal dietary guidelines say three to five 8-ounce cups of black coffee a day can be part of a healthy diet. But the AHA warns that many popular coffee drinks, such as lattes and macchiatos, often include added sugar and fat, making them high in calories.

In the new study, researchers analyzed cognitive assessments for 2,413 people diagnosed with AFib at 14 health centers who enrolled in the Swiss Atrial Fibrillation Cohort Study between 2014 and 2017. Participants, who were an average 73 years old, completed several cognitive tests and reported how many cups of caffeinated coffee they drank during the past 12 months. The researchers did not use a standard cup size, and information was not collected on added sweeteners, creams or flavors.

Researchers also analyzed markers of inflammation, which are associated with both Alzheimer's disease and AFib.

Overall, higher coffee consumption was linked to higher cognitive test scores. Study participants who drank more than five cups of coffee a day scored higher on attention, processing speed and visuomotor coordination than those who drank less than one cup. The cognitive age among those who drank the most coffee was calculated to be 6.7 years younger compared to those who drank the least. And inflammatory markers were more than 20% lower in people who drank more than five cups of coffee a day compared to people who drank less than one cup daily.

"There was a very clear and consistent 'dose-response' association between drinking more coffee and doing better on several different sophisticated cognitive tests," Beer said. "Inflammatory markers decreased with higher coffee consumption, an association that remained after considering variables such as age, sex, body mass index, smoking status, physical activity and a history of stroke."

Prior studies suggest regular coffee's protective effect against cognitive decline in older adults may be due to caffeine and other active ingredients, including magnesium and vitamin B3, the researchers said. Or it may be due to coffee's role in reducing the chemicals that cause inflammation, they suggested.

Dr. José A. Joglar, chair of the 2023 AFib guidelines and a professor of internal medicine at UT Southwestern Medical Center in Dallas, cautioned in the news release that these latest results do not prove coffee prevents long-term cognitive decline.

"Coffee does not seem to worsen AFib, so there is no need to stop drinking it," said Joglar, who was not involved in the new research. "However, we cannot say starting to drink coffee would prevent AFib or prevent long-term cognitive decline."