Is Coffee Good for Your Gut Bacteria? What Microbiome Studies Show

Gut bacteria react to almost everything you eat, but one everyday drink stands out. In a large 2024 study published in Nature Microbiology, coffee was so tightly linked to a single gut bacterium that researchers could often tell coffee drinkers from non-drinkers just by reading their stool samples. So, is coffee good for your gut bacteria? The honest answer: coffee clearly changes which microbes live in your gut, and the changes look neutral to favorable in the studies so far, but no research has yet shown that these shifts make you healthier.

Here is what the main studies actually found, where the evidence stops, and the practical points worth knowing if you drink coffee every day.

Key takeaways

• A 2024 multi-cohort study of 22,867 people in the US and UK, checked against data from 54,198 more, linked coffee to the gut bacterium Lawsonibacter asaccharolyticus.
• Coffee drinkers carried roughly 4.5 to 8 times more of it than non-drinkers, and the link appeared with decaf too.
• A small 2009 trial found three cups a day for three weeks raised Bifidobacterium counts in 16 volunteers.
• These are associations and short-term changes. Their effect on long-term health is not known.

In this article

1. The 2024 Lawsonibacter study
2. Earlier and smaller studies
3. So, is coffee good for your gut bacteria?
4. Practical points for coffee drinkers
5. FAQ

The 2024 Lawsonibacter study: coffee’s gut fingerprint

The study came out of a collaboration between researchers at the University of Trento, Harvard and King’s College London, among others, using data from cohorts including the UK’s ZOE PREDICT program. Here is what they did and found, in plain terms:

• Who was studied: 22,867 people with detailed diet records, in the US and UK, plus public microbiome data from 211 cohorts totaling 54,198 people.
• The headline result: the coffee signal in the microbiome was highly reproducible across populations, and it was driven mostly by one species, Lawsonibacter asaccharolyticus.
• How big the difference was: the research team reported roughly 4.5 to 8 times more of the bacterium in coffee drinkers, with the biggest gap between non-drinkers and moderate-to-heavy drinkers.
• Decaf: the association held for both caffeinated and decaffeinated coffee, which suggests caffeine is not the main driver.
• In the lab: coffee stimulated the growth of the bacterium in vitro.
• Possible link: blood tests on 438 samples showed quinic acid and related compounds were associated with both coffee intake and the bacterium. Quinic acid forms when chlorogenic acids, abundant in coffee, break down.

What the study did not show is just as important. It did not test whether having more Lawsonibacter improves digestion, immunity or any health outcome. Coffee intake was self-reported in food questionnaires, and the design was observational. Very little is known yet about what this bacterium does in people.

Earlier and smaller studies

The 2024 paper built on years of smaller work. Here is how the main pieces of evidence compare:

The 2024 review in Nutrients also noted that intake above about five cups a day has been linked to reflux and other digestive complaints, and that results across studies conflict. More is not automatically better.

So, is coffee good for your gut bacteria?

Put the evidence together and a reasonable reading is this:

1. Coffee changes your gut community. That is now well established, and the coffee signal is one of the strongest of any single food.
2. The changes look benign or favorable. Higher Bifidobacterium and greater diversity are usually seen as positive markers, and no study so far has linked moderate coffee to a harmful microbial shift.
3. The health payoff is unproven. A marker is not an outcome. Nobody has shown that these microbial changes cause better health, and people who drink coffee may differ in other ways too.
4. The driver is probably not caffeine. The decaf result and the quinic acid finding point to coffee’s polyphenols and other compounds.

In short: if you already enjoy coffee in moderation, current microbiome research gives no reason to stop, and some reason to think your gut microbes are adapted to it. It is not a reason to start drinking coffee for gut health, and claims that coffee “heals” or “fixes” the gut go far beyond the data.

Practical points for coffee drinkers

Mind the total caffeine

Most healthy adults can have up to 400 mg of caffeine a day, according to the US FDA and the European Food Safety Authority, with single doses up to about 200 mg. During pregnancy and breastfeeding, EFSA advises staying at or under 200 mg a day. Since the microbiome link appears with decaf too, decaf is an option if caffeine bothers you.

Watch what goes in the cup

Microbiome studies measure coffee, not coffee drinks loaded with syrups and sweetened creamers. If gut health is your goal, black coffee or coffee with a splash of milk keeps you closest to what was studied. Our guide to drinking coffee without sugar has easy ways to taper.

Listen to your own gut

Coffee stimulates the colon in many people, which is why some need the bathroom soon after the first cup. Our article on why coffee makes you poop explains the mechanism, and the one on coffee and acid reflux covers heartburn. If coffee consistently causes pain, diarrhea or reflux, talk to your doctor rather than pushing through.

Choosing your coffee

If you want the ritual with less caffeine, our Peru Decaf is a Swiss Water Process single origin with caramel and citrus notes, and Half Caf blends regular coffee with water-process decaf for half the caffeine. For full-strength cups, browse our single origins. Every bag is roasted 1 to 5 days before delivery.

Coffee and gut bacteria FAQ

Does decaf coffee affect gut bacteria?

Yes, as far as current research shows. The 2024 Nature Microbiology study found the link with Lawsonibacter asaccharolyticus in drinkers of both caffeinated and decaf coffee.

Is coffee a prebiotic?

Coffee contains polyphenols that gut microbes can use, and a small trial saw Bifidobacterium rise. That is prebiotic-like, but coffee is not an established prebiotic.

How much coffee affects the microbiome?

In the 2024 study, the biggest difference in the bacterium was between non-drinkers and moderate-to-heavy drinkers. The 2009 trial used three cups a day.

Can coffee upset the gut?

It can in some people, especially at high intakes. Reflux, loose stools and cramps are common complaints. Reduce the amount or speak to a doctor if symptoms persist.

Sources

1. Manghi P. et al. Coffee consumption is associated with intestinal Lawsonibacter asaccharolyticus abundance and prevalence across multiple cohorts. Nature Microbiology, 2024. DOI 10.1038/s41564-024-01858-9.
2. Study shows links between coffee drinking and gut health, Daily Coffee News, 2025.
3. Coffee consumption linked to specific gut bacterium, MDedge, 2024.
4. Jaquet M. et al. Impact of coffee consumption on the gut microbiota: a human volunteer study. International Journal of Food Microbiology, 2009.
5. Saygili S., Hegde S., Shi X.Z. Effects of coffee on gut microbiota and bowel functions in health and diseases: a literature review. Nutrients, 2024.
6. This everyday drink outranks 150 foods for its impact on your gut health, BBC Science Focus.

Facts checked in October 2026.

This article is for general information only and is not medical advice. If you have a health condition, are pregnant or take medication, ask your doctor before changing your caffeine intake.

Keep reading: Why coffee makes you poop · How decaf is made · Single origins