Coffee affects mental health and stress resistance

The study involved two groups of participants: regular coffee drinkers (consuming 3 to 5 cups per day) and those who rarely consumed coffee. During the experiment, the participants followed a two-week period of complete abstinence from coffee, after which the beverage was introduced back into their diets in a blinded manner, with one group receiving regular coffee and the other receiving decaffeinated coffee. The analysis of biological samples and regular psychological testing allowed researchers to observe changes in the participants’ metabolic profiles and assess the dynamics of their emotional states.

It has been established that coffee consumption leads to a significant increase in the populations of specific bacteria, such as Eggertella sp and Cryptobacterium curtum. These microorganisms play an important role in the secretion of gastric juice and the synthesis of bile acids, which contributes to the natural suppression of pathogenic flora and the prevention of gastrointestinal infections. Additionally, there was an increase in the proportion of Firmicutes-type bacteria, whose presence in the microbiome is statistically correlated with a predominance of positive emotions, particularly in women.

The psychological indicators of the participants improved in both groups after the introduction of the beverage into their diet. The levels of perceived stress, depression, and impulsivity decreased both when caffeine was consumed and when decaffeinated coffee was used. This proves that the antidepressant effect and overall mood stabilization are not only due to the stimulating effects of caffeine on the central nervous system, but also to the secondary chemical compounds that actively interact with the gut microbiome.

Despite the overall positive trends, the researchers identified functional differences depending on the type of beverage. The caffeinated beverage showed a direct correlation with a decrease in anxiety levels, an increase in vigilance and concentration, and a decrease in markers of systemic inflammation in the body. At the same time, drinking decaffeinated coffee led to a noticeable improvement in learning and long-term memory performance. Scientists attribute this effect to the high concentration of polyphenols that remain in the beans after caffeine is removed.

The findings support the concept of a bidirectional relationship between the composition of the microbiome and cognitive processes. Coffee acts as a complex dietary factor that modifies the collective work of microbes and the metabolites they use. The results of this work open up opportunities for integrating coffee into therapeutic diets aimed at correcting psychoemotional conditions and maintaining a healthy digestive balance without the need for psychoactive stimulants.