It’s been a while since scientists began to reach a consensus that whatever’s going on in your gut microbiome is vital, as it plays a major role in both physical and mental well-being. Those billions of microbes are sensitive, constantly shifting in response to diet and lifestyle. Now, a team of researchers says that one of the most common daily habits among billions of people worldwide can radically reshape your gut microbiome: drinking coffee.

A study published in Nature Communications tracked 62 adults through phases of normal coffee use, a forced two-week break, and a controlled reintroduction of either caffeinated or decaffeinated coffee. The goal was to understand how coffee interacts with the gut-brain axis, the communication network linking digestive microbes and the brain.

They found that habitual drinkers had distinct gut microbiomes compared to nondrinkers, with certain bacterial strains more abundant than others. When the study participants stopped drinking coffee, the patterns began to ebb and flow like ocean tides, with strains that were abundant before now retreating as others that were scarcely found reemerged.

This happened whether the coffee was caffeinated or not. That is a more important detail than it seems on the surface, since many of the changes were tied to the plant compounds in coffee called phenolic acids, which can influence how gut bacteria function and what chemicals they produce. A lot of those chemicals contain compounds that influence or affect the range of bodily functions, from brain signaling and gut health to body inflammation.

Coffee Causes Huge Changes In Your Gut Microbiome

Coffee’s effects show up in the billions of microscopic microbes in your gut, and in your behavior, too. Coffee drinkers were noted to be more impulsive and emotional. Yet after a two-week break, both of those measures dropped. When the coffee was reintroduced, the outcomes started to split.

People drinking caffeinated coffee had reduced anxiety and lower stress hormone levels, which sounds counter to what I would expect. Decaffeinated coffee drinkers also saw some benefit after the break, having shown stronger associations with improved sleep, memory performance, and fewer errors on learning tasks.

Coffee drinkers had a lower baseline of inflammatory markers, which is great. But those levels increased in the absence of coffee, then improved again once the coffee returned, regardless of whether it was caffeinated. If you want to reduce body inflammation, drink coffee in any form.

The point is, coffee doesn’t just wake your sleepy butt up in the morning. It is actively changing the complex biological ecosystem within your body, thus influencing how you think, how you feel, how you react to external stimuli, and, overall, how you function day to day.

So fix yourself a cup of brew in the morning and chug it down, knowing it’s changing you for the better.