Meet the coffee-loving gut bacteria: ZOE study

ZOE’s scientists recently published a new paper on the world’s favorite beverage: coffee. 

By analyzing data from more than 22,000 people, they brought to light a fascinating relationship between drinking coffee and the gut microbiome. 

Excitingly, our research was published in the leading journal Nature Microbiology. Here, we’ll outline our intriguing results and what they mean for you. 

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Why did we investigate coffee and the microbiome?

At ZOE, we’re passionate about exploring the relationships between the food we eat and the gut microbiome. As simple as that sounds, the reality is thrillingly complicated.

Your gut microbiome consists of trillions of microorganisms — bacteria, viruses, fungi, and more.

At the same time, as bacteria feast on your recent meal, they produce small molecules called metabolites. Sometimes, these metabolites might be good for your health; sometimes, these metabolites feed other species, which might convert them into different metabolites.  

It’s an extraordinarily complex network of shifting communities all interacting with each other. So, looking for patterns in this biological cacophony is more than a little challenging — where do you begin unraveling it all? 

Thankfully, there are some unusual things about coffee that make it a great place to start:

1. We know coffee affects the microbiome

In previous research, ZOE looked for links between specific food components and distinct gut microbiome signatures. Out of around 150 food and drinks, coffee had the strongest food-microbiome association. 

2. People everywhere love coffee 

Dietary patterns are complex and can vary drastically between countries, cultures, and even members of the same family. Coffee is unusual in that it’s enjoyed worldwide. 

Suppose coffee drinkers in Vietnam, Venezuela, and Venice Beach all have an abundance of one species of gut bacteria compared with non-coffee drinkers in the same regions.

3. A regular ritual

How often do you eat peaches? Many of us would struggle to answer that question accurately. A much easier question to answer is, “How often do you drink coffee?”

Because most people either drink coffee every day or not at all, people tend to report their consumption more accurately than for less common items. 

4. Unique chemistry

On a chemical level, coffee is unlike anything else we consume. It contains many compounds that we rarely get from other foods, making it easier for scientists to trace them in the body.

Also, many foods can change from country to country, or vary due to the way they are cooked or processed. Coffee, on the other hand, has a fairly consistent chemistry, globally.

5. Coffee-microbiome-health links

Drinking coffee is linked to observed health benefits, including gut, brain, and heart health. Some experts suggest that these benefits might be due to the interactions between compounds in coffee and gut microbes. 

This makes it of particular interest to scientists who want to understand how gut bacteria and their metabolites support your health.

What did we find?

In all, we identified 115 species of bacteria that were linked to drinking coffee. Interestingly, the top 10 bacteria with the strongest relationship to coffee were also strongly correlated with drinking decaffeinated coffee. 

This means that the relationship isn’t purely caffeine-related and could help explain why decaf coffee also has health benefits — perhaps caffeine isn’t so important after all.

By far, the microbe with the strongest association with coffee was L. asaccharolyticus — it was on average 6 to 8 times more abundant in coffee drinkers compared with non-drinkers. 

In other words, if you’re a coffee drinker, there’s a very high chance you’ve got a thriving population of L. asaccharolyticus in your intestines right now.

As further evidence of this association, these bacteria were more abundant in those who drank high levels of coffee compared with more moderate consumers. Additionally, using data from 25 countries, we found these same relationships worldwide.

A glimpse into metabolic pathways

In the next phase of the study, we moved into the laboratory to see what else we could learn about the links between coffee and L. asaccharolyticus. 

Firstly, we showed that coffee and decaf coffee stimulates the growth of this bacteria in vitro.

Chlorogenic acid is one of the main polyphenols in coffee. As gut bacteria feed on it, they produce a wide range of other compounds, like quinic acid.

This research found that some of these coffee-related compounds were present at higher levels in the blood of coffee drinkers carrying L. asaccharolyticus. 

We also found that people with L. asaccharolyticus in their gut microbiome had increased levels of hippurate, which is a marker of metabolic and gut health. Hippurate is formed by gut bacteria as they metabolize polyphenols, like those in coffee.

ZOE’s scientists think that L. asaccharolyticus in coffee drinkers may be responding to these polyphenol pathways and could help explain coffee’s health benefits.

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What the study means for you

This study forms a vital scientific building block. As we dig further into the relationship between coffee and gut bacteria, we’ll slowly deepen our understanding of how they interact to support health. 

And if you don’t enjoy the taste of coffee, don’t worry, you don’t need to force it down; there are plenty of other ways to support your gut and overall health.