03.05.2026 23:54
A study conducted in Ireland showed that caffeine-free coffees also have benefits for gut health, mood, and cognitive performance.
Researchers from University College Cork in Ireland compared certain health indicators of 31 people who drank three to five cups of coffee daily with 31 participants who did not drink coffee. At the start of the study, there were no differences between the two groups in terms of body mass index, blood pressure, stress, anxiety, depression, gastrointestinal symptoms, sleep quality, or physical activity. However, significant changes were observed in some immune markers in the blood and certain types of microbes in the gut among coffee drinkers.
THEY DRANK DECAFFEINATED COFFEE FOR THREE WEEKS
To determine whether caffeine was a necessary part of the equation, experts asked 31 coffee drinkers to abstain from daily coffee consumption for two weeks. After this period, the intervention phase began. Participants resumed coffee consumption; 16 people drank caffeinated coffee, while 15 drank decaffeinated coffee, and this process continued for three weeks.
The participants did not know which coffee they were drinking. After coffee consumption resumed, all participants showed coffee-related changes in their gut microbiomes, including species-level changes observed in both caffeinated and decaffeinated coffee. The authors of this research evaluated, 'Both types of coffee reduced stress, depression, impulsivity, and inflammation while improving mood and cognitive performance.'
EFFECTS OF COFFEE ON THE GUT-BRAIN AXIS
Caffeinated coffee was associated with reduced anxiety, psychological distress, and blood pressure, as well as increased attention and improved stress coping skills. Both at baseline and when caffeine was reintroduced, coffee drinkers exhibited higher levels of impulsivity and emotional reactivity compared to non-drinkers. On the other hand, decaffeinated coffee improved sleep quality, physical activity, and memory. These findings revealed that caffeine may have specific effects on mood and cognition, but even decaffeinated coffee could be related to the gut-brain connection.
Microbiologist John Cryan stated that coffee is more than just caffeine, saying, "It is a complex nutritional factor that interacts with our gut microbes, metabolism, and even our emotional health. Our findings show that coffee, whether caffeinated or decaffeinated, can affect health in different but complementary ways."
It was noted that the study was based on the relationship between gut microbe changes and the mood and behavioral changes reported by participants, and therefore may not fully reflect reality. However, it was reported that the research involved a detailed examination comparing how participants processed coffee compounds and matching these differences with metabolic patterns in their gut microbiomes.
Noting that very little is still known about the gut microbiome, Cryan explained, "The relationship between digestive and mental health is increasingly better understood, but the mechanisms behind coffee's effects on the gut-brain axis remain unclear."