New study reveals that coffee has the power to reshape your gut microbiome, influencing mood, stress, and even cognition. The research, published in Nature Communications, is the first to closely examine how coffee interacts with the gut-brain axis, the bidirectional communication network linking your digestive system and brain. To the surprise of some cyclists, the findings suggest that coffee’s benefits extend far beyond its caffeine content.
What happens when you stop and restart coffee?
To uncover coffee’s impact, researchers designed a 3-phase study with 31 regular coffee drinkers and 31 non-coffee drinkers, measuring cognition, stress, mood, immune function, gut microbiome, dietary intake, and metabolite composition at each phase.
Baseline (day 0): All participants completed psychological, cognitive, and physical health assessments, provided stool/urine samples, and tracked diet and caffeine intake.
Washout (days 2–14): The caffeine group abstained from all coffee for 14 days. Measurements (psychological, cognitive, and biological samples) were repeated at the end of this phase. Non-coffee drinkers were only analysed at baseline and did not participate further.
Reintroduction (days 16–35): The caffeine group was split into two blinded subgroups: 15 received 4 cups of decaffeinated coffee daily, and 16 received 4 cups of caffeinated coffee daily for 21 days. Psychological, cognitive, and biological measurements were repeated at the end of this phase.
Gut bacteria, the microscopic heroes
The study identified specific bacteria that thrived in coffee drinkers:
- Eggertella sp. and Cryptobacterium curtum: Linked to acid production and bile acid synthesis, these microbes may help protect against harmful bacteria and infections.
- Firmicutes: A group of bacteria previously associated with positive emotions, particularly in females.
These microbial changes hint at a deeper connection between coffee consumption and digestive health, immune function, and even mental well-being.
Decaf vs. caffeinated, surprising differences
Here’s where it gets interesting for athletes:
Decaffeinated coffee: Participants drinking decaf showed improvements in learning and memory. This suggests that polyphenols and other bioactive compounds in coffee, not just caffeine, may enhance cognitive function. Additionally, decaf drinkers reported improved sleep quality and higher positive affect, indicating potential benefits for recovery and mood stability without the stimulant effects of caffeine.
Caffeinated coffee: Only the caffeine group experienced reduced anxiety, better attention and alertness, and a lower risk of inflammation. Caffeinated coffee also led to a decrease in systolic blood pressure compared to decaf, suggesting cardiovascular benefits. These effects highlight caffeine’s role in enhancing focus, reducing stress, and supporting physical resilience during intense training or competition.
As Professor John Cryan, the study’s corresponding author, notes: “Coffee is more than just caffeine. It’s a complex dietary factor that interacts with our gut microbes, our metabolism, and even our emotional well-being.”
Practical takeaways for cyclists
Consistency matters: The study’s participants consumed 4 cups daily.
Decaf has its place: If you’re sensitive to caffeine or training late in the day, decaf could still offer cognitive and gut health benefits without the stimulant effects.
Listen to your body: Pay attention to how coffee affects your digestion, energy, and mood. Everyone’s microbiome is unique, so experiment to find what works best for you.
Coffee isn’t just a pre-ride ritual or a mid/post-ride reward. It’s a performance-enhancing, gut-boosting, andmood-stabilising powerhouse. Whether you opt for caffeinated or decaffeinated, the compounds in coffee interact with your microbiome in ways that could give you a subtle but meaningful boost to your well-being.