Research Shows Possible Effect of Coffee on Bowels

New research has shown that coffee suppressed bacteria and increased muscle motility in an animal study, regardless of its caffeine content.

Xuan-Zheng Shi, PhD, of University of Texas Medical Branch, Galveston, Texas, and colleagues found that when rats were fed coffee for 3 days, the overall bacteria counts in their feces were decreased. However, more research will be needed to determine whether these changes favor firmicutes – “good bacteria – or enterobacteria.

“When rats were treated with coffee for three days, the ability of the muscles in the small intestine to contract appeared to increase,” said Xuan-Zheng Shi, PhD, lead author of the study and associate professor in internal medicine at the University of Texas Medical Branch, Galveston. “Interestingly, these effects are caffeine-independent, because caffeine-free coffee had similar effects as regular coffee.”

Shi presented these results at Digestive Disease Week 2019.

In the study, the researchers prepared a coffee solution by dissolving 100% Arabica coffee powder with hot water, with further centrifugation and filtration. They also mixed the coffee solution with gut bacteria in petri dishes. The solution was administered to rats for 3 days, and microbiota abundance and composition were measured.

Compared with a control, growth of microbiomes of the intraluminal colon contents was significantly suppressed when the coffee solution was used. Coffee treatment in vivo also significantly suppressed gut microbiome. In addition, coffee treatment in vitro showed a stimulating effect on rhythmic physic contractions and tonic contractions in the ileal and colonic smooth muscle. Decaffeinated coffee increased smooth muscle contractility to a similar extent as regular coffee.

The results support the need for additional clinical research to determine whether coffee drinking might be an effective treatment for post-operative constipation, or ileus, in which the intestines quit working after abdominal surgery, according to Shi and colleagues.

Shrilakshmi H, Shi D, Lin YM, Shi XP. SU1625 – in vivo and in vitro effects of coffee on gut microbiota and smooth muscle contractility in rats. Gastroenterology. 2019;156:S-587.