Both caffeinated and decaffeinated coffee can boost mood and mental performance by influencing gut microbes. Researchers found that polyphenols in coffee drive many of these benefits. The findings come from a controlled trial involving 62 healthy adults.
John Cryan at University College Cork led the study with colleagues from Italy. Participants included regular coffee drinkers and non-drinkers. Regular users stopped coffee for two weeks before resuming either regular or decaf versions for three weeks. Scientists tracked changes through blood, saliva, urine and stool samples along with mood and cognition tests.
