New ZOE Study Helps to Explain the Health Benefits of Coffee

ZOE’s scientists recently published a new paper in the leading journal Nature Microbiology, on the world’s favourite beverage: coffee.

The paper details the analyses of data taken from more than 22,000 people and reveals a fascinating relationship between drinking coffee and the gut microbiome. 

The study also offers a glimpse into how gut bacteria can interact with certain chemicals in coffee, suggesting ways in which coffee might support health.

Why did ZOE investigate coffee and the microbiome?
ZOE went into the study with the knowledge of certain details in the relationship between coffee and the microbiome:

1. Coffee affects the microbiome
   In previous research, ZOE looked for links between specific food components and gut microbiome signatures. Out of around 150 food and drinks, coffee had the strongest food-microbiome association.
   
   
2. People everywhere love coffee
   While dietary patterns are complex and can vary drastically between countries and cultures, coffee is somewhat of an anomaly in that it is regularly enjoyed worldwide. With this in mind, ZOE can more confidently assume that coffee is a leading factor influencing gut microbiome: as they describe it, 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. If this is the case, it can safely be assumed that this is due to coffee intake, as this is likely to be one of the few overlaps between the three diets.
   
   
3. A regular ritual
   Because most people either drink coffee every day or not at all, they tend to report their consumption more accurately than for less common foods and drinks.
   
   
4. Unique chemistry
   On a chemical level, coffee is unlike anything else we consume in that it contains many compounds that we rarely get from other foods, making it easier for scientists to trace them in the body.
   
   
5. Coffee-microbiome-health links
   Drinking coffee is linked to observed health benefits, including gut, brain, and heart health, and some experts suggest that these benefits might be due to the interactions between compounds in coffee and gut microbes.

What did ZOE find?
The study identified 115 species of bacteria that were linked to drinking coffee and, interestingly, the top 10 bacteria with the strongest relationship to coffee were also strongly correlated with drinking decaffeinated coffee. This suggests that the relationship between coffee and gut microbiome is not purely determined by caffeine content and could help explain why decaffeinated coffee also offers health benefits.

What’s more, through the study ZOE found they could determine with high accuracy who drank coffee just by analysing their gut microbiome.

• The microbe with the strongest association with coffee was L. asaccharolyticus, which was on average 6 to 8 times more abundant in coffee drinkers compared with non-drinkers.
  
  
• This suggests that if you are a coffee drinker, there is a very high chance that you will have a thriving population of L. asaccharolyticus in your intestines.
  
  
• As further evidence of this association, these bacteria were more abundant in those who drank high levels of coffee compared with more moderate consumers and, using data from 25 countries, ZOE found these same relationships present worldwide.

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

• Firstly, they found that coffee and decaffeinated 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 such as quinic acid, which experts believe might be important for coffee’s health benefits. Studies show that quinic acid, an antioxidant, helps fend off bacteria and viruses, and may also reduce the risk of type 2 diabetes, slow cancer, and reduce pain.
  
  
• This research found that some of these coffee-related compounds were present at higher levels in the blood of coffee drinkers carrying L. asaccharolyticus.

ZOE 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 metabolise polyphenols, like those found in coffee, and ZOE’s scientists think that L. asaccharolyticus in coffee drinkers may be responding to these polyphenol pathways, helping to explain the health benefits of coffee.