I just read a 2026 Nature Communications study on coffee and the microbiota-gut-brain axis, the two-way link between your gut bacteria and your brain. Sixty-two adults. The coffee drinkers quit for 2 weeks, then restarted with caffeinated or decaf.
What stood out to me:
The Gut Shift: Coffee drinkers carried more of specific gut bacteria, including Cryptobacterium and Eggerthella. Restarting coffee shifted those species again, whether caffeinated or decaf.
Decaf vs. Caffeinated: Caffeinated lowered anxiety and sharpened attention. Decaf improved sleep, physical activity, and memory. Both lowered stress and depression scores.
The Reset Effect: Two weeks off coffee reduced impulsivity and emotional reactivity, and withdrawal symptoms eased by day 4.
I love that the rest of the cup, not just the caffeine, does real work in the body.
Full write-up: https://nature.com/articles/s41467-026-71264-8
