Coffee is one of the most popular and widely consumed beverages around the world. Thanks to its effects, it can help us fight sleep or stay alert during the day, but its effects go far beyond. In addition to caffeine, coffee contains more compounds that interact with our body, such as plant compounds that can be processed by the microorganisms in our gut, causing significant effects for the body. That is why, now science seeks to understand how habitual consumption of this beverage directly affects digestion, mood, and some brain functions, such as attention and memory.
A recent study published in the Nature Communications scientific journal (which you can consult through this link) analyzed the relationship between coffee consumption, the gut microbiota, and cognition, that is, the processes our brain carries out that allow us to learn, retain information and respond to various external stimuli. The research also focused on exploring the so-called gut-brain axis, a bidirectional communication pathway between intestinal microorganisms and the nervous system. The results of the analysis showed significant differences between those who habitually drank coffee and those who did not, although it is important to note that the authors emphasize that more research is still needed to understand how these changes relate and what implications they have for health.
How coffee affects your gut and your brain
For this study, the scientists included 62 healthy adults aged 30 to 50, half of whom consumed coffee and the other half did not. The tests consisted of withdrawing coffee consumption for two weeks and reintroducing it into the routine for three weeks for the group that did consume it habitually, whether in caffeinated or decaffeinated form. Throughout the stages of analysis, the researchers collected gut and metabolic samples, in addition to evaluating aspects related to behavior, mood and memory. With this study design, changes associated with both cessation of consumption and its reintroduction could be observed, although, due to the small sample size, it is not possible to generalize the results to the rest of the population.
One of the main findings was that habitual coffee drinkers showed large differences in the composition of the gut microbiota after consuming the beverage. There was a higher relative presence of bacteria from the genera Cryptobacterium and Eggerthella, as well as lower levels of certain substances, such as indole-3-propionic acid, indole-3-carboxaldehyde, and gamma-aminobutyric acid, a neurotransmitter involved in the regulation of nervous system activity. These results show how habitual coffee consumption can become related to changes in the intestinal environment. However, it cannot be concluded that all these variations are inherently harmful or beneficial.
Some differences in behavior and memory measures were also recorded in the study. At the start of the analysis, people who habitually consumed coffee scored higher on scales of emotional reactivity and impulsivity compared with those who did not, while the group that did not drink coffee showed better performance on certain memory assessments. However, these differences do not mean that coffee necessarily causes impulsivity or memory impairment. After stopping its use and reintroducing it, participants were able to experience changes in several evaluated measures, with different results depending on whether they received caffeinated or decaffeinated coffee. For example, those who were given decaffeinated coffee showed improvements in certain memory tests, while the group that consumed regular coffee exhibited changes in certain anxiety and cognitive performance evaluations.
Another important aspect was that some s substances present in the gut samples changed when participants stopped drinking coffee, while their reintroduction caused new variations in the microbiota, even if the beverage did not contain caffeine. This may be the result of other components of coffee, such as phenolic acids, potentially intervening in the relationship between the beverage and the intestinal microorganisms. Still, the researchers found certain associations between coffee substances, the microbiota, and the cognitive measures, but it was not possible to demonstrate with certainty that changes in the gut were the cause of the differences in behavior or memory in the analysis subjects.
So, is drinking coffee bad for brain processes?
Taken together, this study gives us new clues about the relationship that may exist between constant coffee consumption, the gut, and brain function, but its results are not entirely conclusive, and therefore, it cannot be stated that drinking coffee improves memory, causes emotional changes, or has the same effects in all people in 100% of cases. Understanding these connections requires more field research, with more participants and other studies capable of establishing with greater precision the mechanisms involved in these processes. For now, coffee can be related to changes in both the microbiota and some cognition and behavior measures, but this is a connection that science is still exploring.
