Coffee has been shown to influence aspects beyond providing energy, alertness, and focus. Research published in Nature Communications in April indicates that this beverage, even when caffeine-free, has the capacity to modify the gut microbiome and generate benefits related to mood, memory, sleep, and cognitive functions.
The researchers conducted an evaluation with 62 healthy adults, dividing them into two groups: half consumed three to five cups of coffee daily, and the other half did not have this habit. The analysis included assessments of mood, cognitive ability, stress level, physical health, gut microbiota composition, and metabolites found in urine and stool samples.
After the initial assessment phase, individuals who drank coffee regularly went two weeks without consuming the beverage or any other source of caffeine. Subsequently, some returned to consuming caffeinated coffee, while the other half spent three weeks consuming the decaffeinated version.
Consumption Results
Both conventional and decaffeinated coffee were associated with improved mood, reduced stress, and decreased impulsivity after the abstinence period. Caffeinated coffee showed effects on attention and anxiety, while the decaffeinated version showed a greater correlation with improved memory, sleep, and even physical activity.
Diogo Toledo, a nutritionist at Einstein Israelite Hospital, commented that this study corroborates the growing notion that the gut and brain have a direct connection. He emphasized that the fact that the study demonstrated this even with decaffeinated coffee indicates that the influence is not limited only to caffeine, given that the beverage contains hundreds of bioactive compounds, such as antioxidants and polyphenols.
Toledo explained that it is already known that the gut is involved in the production of inflammatory substances and neurotransmitters that can affect cognition, sleep, memory, and mood. This communication occurs through the nervous system, the immune system, and gut bacteria, making the gut-brain axis a topic of great interest in contemporary medicine.
Impact on Gut Microbiota
The study also revealed significant transformations in the gut microbiota. Coffee consumers exhibited higher levels of certain bacteria linked to positive health outcomes. Furthermore, during the break from consuming the beverage, changes were observed in metabolites related to metabolism and brain function.
The nutritionist reported that there is increasing evidence that the gut microbiome is a highly dynamic system that reacts quickly to ingested foods and beverages. Initially, coffee consumers presented greater emotional reactivity and impulsivity, which may be linked to the stimulating effects of caffeine on the central nervous system. Diogo Toledo pointed out that caffeine elevates neurotransmitters such as dopamine and norepinephrine, which improves disposition and attention, but can also make some people more emotionally agitated.
However, the study's authors mentioned limitations, such as the small sample size and the exclusive use of instant coffee. The doctor from Einstein noted that the preparation method significantly alters the final composition of the beverage, as espresso, filtered, capsule, French press, or instant coffee differ in the amount of polyphenols and other bioactive compounds. Therefore, the effects cannot be generalized to all preparation methods.
International guidelines establish consumption of up to 400 mg of caffeine per day as safe, which is equivalent to approximately three or four cups, depending on the preparation method. However, there is no universal ideal dose, as tolerance to the beverage is influenced by genetic factors and the speed at which each organism processes caffeine.
