A new study suggests coffee consumption may reshape the microbiota–gut–brain axis independently of caffeine. Researchers found that regular coffee drinkers showed distinct gut microbiome patterns, including higher levels of Cryptobacterium and Eggerthella species, alongside lower concentrations of neuroactive metabolites such as GABA and indole-derived compounds. Behaviourally, coffee drinkers demonstrated greater impulsivity and emotional reactivity, while non-coffee drinkers performed better in memory tasks. Some microbiome and metabolite changes reversed after coffee abstinence, and reintroducing coffee triggered rapid microbial shifts even without caffeine exposure. Integrated analyses identified nine metabolites including caffeine, theophylline, and phenolic acids — closely linked to microbial composition and cognitive outcomes.The findings highlight a previously underappreciated connection between coffee intake, gut microbiota, and brain-related function, suggesting coffee’s physiological effects may extend well beyond stimulation alone.