Nutrition & DietCoffee Rewires Your Gut and Brain Through Multiple Pathways Beyond Caffeine
Researchers at University College Cork found that drinking coffee — caffeinated or decaf — actively changes gut bacteria in ways that improve mood and reduce stress. The study, published in Nature Communications, compared 31 coffee drinkers with 31 non-drinkers, tracking gut microbiome shifts, metabolites, and psychological states. After a two-week coffee abstinence period, participants reintroduced either caffeinated or decaf coffee. Both groups reported lower stress, depression, and impulsivity. Surprisingly, only decaf drinkers showed improvements in learning and memory, pointing to polyphenols rather than caffeine as the driver. Caffeine, meanwhile, boosted focus and reduced anxiety. Specific bacteria including Eggertella sp and Firmicutes increased in coffee drinkers, suggesting coffee shapes gut health through multiple biological pathways.
