University College Cork study finds coffee may influence gut‑brain axis

Researchers at University College Cork examined how regular coffee consumption affects the microbiota‑gut‑brain axis. The study compared 31 habitual coffee drinkers (three to five cups daily) with 31 non‑drinkers, assessing mood, stress, attention, memory and other cognitive functions. Stool and urine samples were analyzed for gut bacteria and metabolites. After a two‑week coffee‑free washout, participants were randomly assigned to receive either caffeinated or decaffeinated coffee for three weeks. Results showed measurable changes in gut microbial composition and metabolite profiles that correlated with variations in mood and cognitive performance, suggesting that coffee’s impact extends beyond caffeine’s immediate stimulant effect. The authors caution that the findings do not prove coffee can treat depression, anxiety or cognitive impairment, but they highlight a more complex relationship between coffee, the gut microbiome and brain function.