Purgative properties: New US research pinpoints coffee and bowel movement connection
Rat study shows that caffeine does not necessarily have anything to do with bowel disruptions
23 May 2019 --- Coffee has long been thought to increase bowel movement, but until now researchers have not pinpointed the specific reason or mechanism why this is so. The accelerated mobilization of bowel movements has been tested in a rat model, with US researchers finding that muscles in the lower intestines and colons of rats showed increased ability to contract after just a brief period of coffee ingestion. The findings also revealed the same reaction from the rats for regular and caffeine-free coffee.
However, according to researchers from the University of Texas Medical Branch, Galveston, the findings support the need for additional clinical research. More work is needed to determine whether coffee drinking might be an effective treatment for post-operative constipation, or ileus, in which the intestines stop working after abdominal surgery, the authors note.
The researchers examined changes to bacteria when the fecal matter was exposed to coffee in a petri dish, and by studying the composition of feces after rats ingested differing concentrations of coffee. This happened over a three day period.
Changes to smooth muscles in the intestine and colon, and the response of those muscles when exposed directly to coffee were also noted.
The growth of bacteria and other microbes in fecal matter in a petri dish was suppressed with a solution of 1.5 percent coffee, and growth of microbes was even lower with a 3 percent solution of coffee. Decaffeinated coffee had a similar effect on the microbiome, the study found.
The overall bacteria counts in rats’ feces were also decreased. However, it is not known whether these changes favor firmicutes, considered "good" bacteria, or enterobacteria, which are regarded as negative. Researchers also call for more work to determine this.
“When rats were treated with coffee for three days, the ability of the muscles in the small intestine to contract appeared to increase,” says Xuan-Zheng Shi, Ph.D., 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.”
Dr. Shi recently presented data from the study, “In vivo and in vitro effects of coffee on gut microbiota and smooth muscle contractility in rats,” as part of at Digestive Disease Week (DDW) 2019. This is an educational forum for academicians, clinicians, researchers, students and trainees working in gastroenterology, hepatology, GI endoscopy, gastrointestinal surgery and related fields. It was held in San Diego, California.
