Coffee is more than your morning wake-me-up. The health benefits of coffee extend beyond the caffeine boost. Researchers are now investigating how coffee interacts with the gut–brain axis, the communication network between the digestive system and the brain.A recent study published in Nature Communications suggests that Regular coffee drinking can shape the gut microbiome and influence mood and stress.
The hidden side of coffee
Coffee consumption is linked with digestive and mental health benefits. However, the exact mechanisms behind these effects remain unclear. The researchers here investigated how coffee consumption affects the microbiota–gut–brain axis — the bidirectional communication between the gut microbiome and the brain — using a wide range of measures.To understand this, the researchers compared 31 regular coffee drinkers with 31 people who do not drink coffee. The participants in this study also completed psychological assessments. Their diet and caffeine intake were tracked. The researchers also analyzed stool and urine samples to observe changes in gut bacteria and emotional state. In this study, ‘coffee drinkers’ are defined as individuals who typically consume 3–5 cups of coffee per day. This level is considered safe and moderate by the European Food Safety Authority (EFSA).During the study, the coffee drinkers stopped consuming coffee for two weeks. The researchers collected samples and monitored the participants’ mental health. They noticed a clear shift in metabolites produced by gut microbes in regular coffee drinkers, compared with non-coffee drinkers.After this phase, the participants were gradually reintroduced to coffee without knowing whether they were drinking caffeinated or decaffeinated coffee. Half of them were given decaf, while the other half consumed regular coffee. Both groups reported improvements in mood, including lower levels of stress, depression and impulsivity. These results suggest that coffee can enhance mood even without caffeine.
Gut bacteria and coffee consumption
In coffee drinkers, the researchers noticed an increase in bacteria such as ‘Eggertella sp.’ and ‘Cryptobacterium curtum’, compared with non-coffee drinkers. Eggertella sp. is thought to contribute to gastric and intestinal acid secretion, while the latter is believed to be involved in bile acid synthesis. Both play a crucial role in removing unhealthy gut bacteria and stomach infections. The researchers also noticed increased ‘Firmicutes’ bacteria, which are linked with positive emotions in females.
Decaf vs caffeine effects on the brain
The researchers found a noticeable improvement in learning and memory in those who consumed decaffeinated coffee. This points to the fact that components other than caffeine, such as polyphenols, are responsible for these cognitive benefits. However, they also found that only caffeinated coffee was associated with reduced feelings of anxiety, as well as improved vigilance and attention. Caffeine was also linked to a reduced risk of inflammation.
What you should know
Coffee is more than just caffeine. “Public interest in gut health has risen hugely. The relationship between digestive and mental health is also increasingly better understood, but the mechanisms behind coffee’s effects on this gut–brain axis have remained unclear,” said Professor John Cryan, corresponding author of the study and principal investigator at APC Microbiome Ireland, University College Cork.“Our findings reveal the microbiome and neurological responses to coffee, as well as their potential long-term benefits for a healthier microbiome. Coffee may modify what microbes do collectively, and which metabolites they use. As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to be harnessed as a further intervention as part of a healthy, balanced diet,” he added.“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,” said Professor Cryan. “Our findings suggest that coffee, whether caffeinated or decaffeinated, can influence health in distinct but complementary ways,” Prof. Cryan concluded.So, yes, your morning joe is doing more than just waking you up.
