Drinking coffee — both caffeinated and decaffeinated — changes the composition of the gut microbiome and influences the gut-brain connection, improving mood and cognitive function. That is the conclusion of scientists at the APC Microbiome Ireland research centre at University College Cork, who studied the drink's effect on the gut-brain axis, according to infohub.kz.
The study was published in the journal Nature Communications with support from the Institute for Scientific Information on Coffee (ISIC). It involved 31 coffee drinkers who consumed 3–5 cups a day and 31 people who do not drink the beverage.
During the experiment, the coffee lovers first gave it up for two weeks — which caused significant shifts in the profile of their gut metabolites. The drink was then reintroduced to their diet blindly: one group received regular coffee, the other decaffeinated. After resuming intake, both groups reported lower levels of stress, depression and impulsivity.
Regular coffee consumers also showed high levels of the bacteria Eggertella sp, Cryptobacterium curtum and Firmicutes, which are involved in acid secretion and bile production and are linked to positive emotions.
The study found differences in the effects of the two types of drink: decaffeinated coffee improved learning and memory scores, which is attributed to the action of polyphenols and antioxidants, while regular coffee reduced anxiety levels, increased alertness and lowered the risk of inflammation.
Professor John Cryan noted that coffee should be viewed as a complex dietary factor that affects gut health and emotional well-being not only through caffeine.