How Coffee and Decaf Impact Gut Microbiota, Memory, and Stress
- Researchers at the University College Cork published a study in Nature Communications examining how coffee consumption alters human gut microbiota, cognitive performance, and emotional well-being, according to SOURCE...
- The investigation tracked 31 regular coffee drinkers who consumed between three and five cups daily.
- John Cryan, a neurobiologist and researcher at APC Microbiome Ireland, explained that the beverage interacts directly with intestinal microbes and metabolic pathways.
Researchers at the University College Cork published a study in Nature Communications examining how coffee consumption alters human gut microbiota, cognitive performance, and emotional well-being, according to SOURCE 4.
The investigation tracked 31 regular coffee drinkers who consumed between three and five cups daily. Participants completed a two-week washout period without coffee before reintroducing the beverage, allowing scientists to monitor biological and psychological shifts.
Microbiome Shifts Driven by Regular Intake
John Cryan, a neurobiologist and researcher at APC Microbiome Ireland, explained that the beverage interacts directly with intestinal microbes and metabolic pathways. Maria João Duarte, a nutritionist, explained in an article shared with VERSA that coffee has multiple health benefits proven by studies, including a reduction in all-cause and specific-cause mortality and increased longevity.
John Cryan, APC Microbiome Ireland
Polyphenol compounds present in the coffee beans reach the colon largely intact, where enterocytes ferment them into antioxidant metabolites. Among the identified changes, the investigation highlighted the presence of bacteria such as Eggertella sp. and Cryptobacterium curtum, alongside variations in microorganisms from the Firmicutes group.
Distinct Effects of Caffeinated and Decaffeinated Variants
The investigation identified diverging outcomes depending on whether participants consumed caffeinated or decaffeinated coffee. Participants who consumed decaffeinated coffee achieved better results in memory tests related to learning and word recall, including location and word list exercises. Researchers suggest these effects may be linked to compounds such as polyphenols, which nourish enteric bacteria and trigger a favorable metabolic cascade for cognitive performance. Conversely, caffeinated coffee was associated with alterations in attention and mental alertness, alongside a reduction in indicators of psychological fatigue, anxiety, and perceived emotional distress or stress. Researchers noted this may reflect the combination of caffeine’s stimulant effect with other biological mechanisms.
Moderate Consumption Limits and Gut Motility
Examining broader consumption patterns, a 2024 review analyzed studies on human and rodent gut ecosystems. Moderate intake of fewer than four cups daily associated with increased bifidobacteria populations and reduced enterobacteria counts.
SOURCE 3 reported that ingestion stimulates gastric acid and bile acid synthesis through hormones like gastrina and colecistocinina, accelerating colon contractions regardless of caffeine content. However, consumption exceeding five daily cups correlated with an increased risk of gastroesophageal reflux and progression of Crohn’s disease symptoms.
Temporary Changes Following Interruption
Investigators observed that interrupting coffee consumption and subsequently resuming it triggers acute, temporary shifts across fecal and urinary biomarkers.
While the findings point toward complementary health impacts, researchers emphasized that the trial was preliminary and involved a small cohort. Consequently, the data cannot establish definitive causal relationships or prove that coffee consumption prevents mental health disorders.