Regular coffee drinking was associated with greater gut microbial richness and more colon contractions in a study of 61 healthy adults in Denmark. The research, led by the University of Copenhagen, also found a lower pH in the small intestine among more frequent coffee drinkers, indicating a more acidic environment.
The findings are based on comparisons of participants’ coffee habits, not an experiment that assigned people how much to drink. The researchers said the study therefore cannot show that coffee caused the differences or establish whether the changes benefit health.
Capsule tracked conditions inside the gut
Participants were grouped according to how often they drank coffee. The regular-consumption group reported drinking one to five cups a day on more than three of the eight study days; the other group drank coffee less frequently.
Fifty of the 61 participants swallowed a wireless capsule that recorded measurements as it moved through the digestive tract, including pH and intestinal contractions. Researchers also assessed the gut microbiota. Regular coffee drinkers had greater microbial richness, while higher coffee intake was linked with more contractions in the colon.
Colon contractions help move intestinal contents through the digestive system. The study did not show that the observed difference prevents constipation or improves health.
Lead researcher Francesca Bucci, a PhD student at the University of Copenhagen, said the results suggest habitual coffee consumption may affect intestinal physiology. Henrik Munch Roager, an associate professor who leads a research group in the university’s Department of Nutrition, Exercise and Sports, said earlier research on coffee’s effects in the digestive system makes a role for coffee plausible.
The team said a controlled study that sets participants’ coffee intake would be needed to test whether coffee causes the changes and to examine how it may affect gut function. The findings were reported in Gut Microbiology. The University of Copenhagen also outlined the research.
Clayton Ward