New study reveals coffee’s positive gut impacts, even without caffeine

New research is looking at the positive effects of coffee on the gut-brain connection.

In the small study, published April 21 in Nature Communications, researchers found regularly drinking coffee − both caffeinated and decaffeinated versions − can affect the gut microbiome, influencing mood and stress.

Researchers studied 31 coffee drinkers and 31 non-drinkers via psychological tests, caffeine and food diaries as well as stool and urine samples to understand changes in their microbiome, mood and stress levels.

Those who drank coffee − both caffeinated and decaffeinated − reported lower perceived stress, depression and impulsivity scores. This suggests drinking coffee significantly improved mood, regardless of caffeine content, according to the authors.

"Coffee is more than just caffeine − it’s a complex dietary factor that interacts with our gut microbes, our metabolism, and even our emotional wellbeing," author John Cryan said in a news release. "Our findings suggest that coffee, whether caffeinated or decaffeinated, can influence health in distinct but complementary ways."

Researchers also found certain bacteria, including those that fight against unhealthy gut bacteria and stomach infections, were higher in coffee drinkers compared to non-coffee drinkers. Drinking caffeinated coffee specifically was associated with reduced feelings of anxiety, improved vigilance and attention and a reduced risk of inflammation.

"Our findings reveal the microbiome and neurological responses to coffee, as well as their potential long-term benefits for a healthier microbiome," Cryan added. "As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to also be harnessed as a further intervention as part of a healthy balanced diet."

While this study is small and there is conflicting evidence on the health benefits of coffee, the research adds to a growing body of research focused on the gut microbiome as gut health continues to be a buzzword in the wellness space.