Regular coffee intake linked to changes in gut microbiome and intestinal activity
A University of Copenhagen study found that frequent coffee consumption is associated with greater gut bacterial diversity, lower small-intestine pH and increased colon contractions, suggesting potential implications for constipation treatment.
A research team at the University of Copenhagen reported that people who drink coffee regularly show measurable changes in both the composition of their gut microbiota and the physiological behavior of the gastrointestinal tract. The study involved Danish volunteers who swallowed a small electronic capsule that recorded transit time, temperature, pH and intestinal contractions as it moved through the digestive system. Participants were divided into frequent coffee drinkers – those consuming one to five cups a day on most study days – and less frequent drinkers.
Analysis of the capsule data indicated that frequent coffee consumers had a higher diversity of gut microorganisms and a significantly lower pH in the small intestine compared with the lower-consumption group. The researchers also observed a greater number of colon contractions among the high-intake participants.
"Contractions in the gut can support healthy digestion, help prevent constipation and keep the intestinal muscles in good condition," said Francesca Bucci, first author and PhD student in the Department of Nutrition, Exercise and Sports.
The study authors cautioned that the findings do not prove causation and that the health impact of the lower intestinal pH remains unclear. Senior author Henrik Munch Roager noted that previous research has shown coffee influences digestive processes such as stomach acid secretion, providing a plausible link to the observed effects.
"We already know from other studies that coffee can influence a range of processes in the digestive system, including acid secretion in the stomach. So there are good reasons to believe that what we are seeing is not merely coincidence," Roager said.
The researchers suggested that controlled intervention trials, in which coffee intake is systematically varied, would be the next step to confirm the relationship and explore therapeutic applications for constipation and irregular bowel movements.
"A great many people struggle with constipation and irregular bowel movements. If we can understand how coffee affects digestion and intestinal contractions, it may be possible to use that knowledge to stimulate gut motility in a natural way. That would be extremely valuable," Roager added.