Both caffeinated and decaffeinated coffee have been shown to improve mood, memory, and stress levels, according to a new study. The findings suggest the benefits of coffee extend beyond just caffeine.
Researchers conducted a randomized crossover trial to examine coffee’s effects on mood, cognition, and the gut. The study involved healthy adults who went through three phases: a period of regular coffee consumption, a washout phase with no coffee, and a reintroduction phase where they received either caffeinated or decaffeinated coffee.
Participants completed cognitive tasks testing attention, memory, and mental flexibility. They also reported on mood, stress, and emotional reactivity. Researchers analyzed the gut microbiome using advanced sequencing and tracked metabolites, small molecules produced during digestion that can influence brain function.
After the washout period, both caffeinated and decaffeinated coffee led to improvements in mood. Participants reported lower stress, fewer symptoms of depression, and less impulsivity. This indicates caffeine is not solely responsible for coffee’s effects.
Caffeinated coffee was more strongly linked to reduced anxiety and better attention and vigilance. Decaf was associated with better sleep, improved memory and learning, and higher levels of physical activity.
Coffee also changed the composition of the gut microbiome, increasing certain bacterial species and shifting the production of metabolites linked to brain health and inflammation. This is due to the gut-brain axis, where microbes in the gut produce neurotransmitters and immune signals that the brain uses.
The research broadens the understanding of coffee’s effects. Coffee contains a complex mix of compounds, including polyphenols, which are plant-based molecules that can fuel beneficial gut bacteria. These downstream effects may explain why coffee has been linked to better long-term brain and metabolic health.
For people sensitive to caffeine or trying to cut back, decaf is not a “downgrade.” It provides many of the same gut and mood-related benefits without the stimulant effect. The study was published in Nature Communications.
