What your coffee might be doing for your gut

July 30, 2026
2 min read

We all know coffee wakes you up. What's less well known is what it might be doing further down, in your gut, and the research on this has grown a lot in the last couple of years.

The gut bacteria study

In 2024, researchers led by Nicola Segata analysed data and stool samples from more than 75,000 people across 25 countries, comparing coffee drinkers to non-drinkers. Out of more than 150 foods and drinks tested, coffee showed the strongest link to a person's gut bacteria makeup, more than any other single item in the study.

The standout finding was a bacterium called Lawsonibacter asaccharolyticus. Regular coffee drinkers had somewhere between six and eight times more of it in their gut than non-drinkers, and this held up across all 25 countries studied, regardless of what else people ate or where they lived. This bacterium is linked to producing butyrate, a compound that plays a role in gut health and reducing inflammation.

The gut-brain study

A newer study out of APC Microbiome Ireland at University College Cork, published this year in Nature Communications, looked further into what coffee might be doing for the connection between gut and brain. It's a smaller study, 31 regular coffee drinkers compared with 31 non-drinkers, but it's the first of its kind to look this closely at the mechanism behind coffee's effects on this system.

The results were more nuanced than a simple "coffee is good for your brain" headline. Decaf drinkers in the study showed improvements in learning and memory, suggesting it's compounds other than caffeine, potentially polyphenols, doing some of the work. Regular caffeinated coffee drinkers showed a different pattern, reduced anxiety and better attention, but not the same memory benefit. Both forms of coffee shifted gut bacteria composition in ways linked to the gut-brain communication pathway.

It's an interesting, and growing, area of science, and we'll be watching where it goes. In the meantime, we just happen to think a good cup of cold drip is worth having either way.