Study of 62 Adults Finds Coffee Reshapes Gut Bacteria, Lifting Mood and Memory

3 articles · Updated · PsyPost · Jun 2

A 62-person study found regular coffee intake altered gut-bacteria composition, with measurable links to mood, memory and physiology in healthy adults aged 30 to 50.
After a 2-week coffee withdrawal, habitual drinkers showed drops in impulsivity and emotional reactivity; 3 weeks of reintroduction then lowered perceived stress and depressive symptoms in both coffee groups.
Caffeinated coffee delivered added benefits—lower anxiety, less psychological distress and reduced inflammatory proteins—while decaf improved sleep quality, physical activity and memory-test performance.
Stool and urine analyses tied those effects to shifts in specific bacterial strains and in caffeine and polyphenol metabolism, though overall microbiome diversity did not change.
The Nature Communications authors said the effects were subtle and not proof coffee prevents dementia or Parkinson's, but the findings point to gut-microbiome mechanisms that could inform larger personalized nutrition studies.

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