The researchers gave rats coffee with caffeine and decaffeinated coffee for three days and saw that throughout the period, their small intestines had an improved ability to contract, regardless of the level of caffeine content.
"Interestingly, these effects are caffeine-independent, because caffeine-free coffee had similar effects as regular coffee, Shi pointed". Yet, researchers at the University of Texas, Galveston, are studying rats to find out exactly why this seems to be true.
"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, lead author of the study.
Coffee has always been known to increase bowel movement, but no one knows exactly why. When exposed to 1.5 percent coffee, they found the growth of bacteria and other microbes in the fecal matter were suppressed.
In a study presented as part of Digestive Disease Week, a team from the University of Texas Medical Branch fed rats a continuous diet of coffee, as well as mixing the liquid in with gut bacteria and petri dishes. The study also documented changes to smooth muscles in the intestine and colon, and the response of those muscles when exposed directly to coffee.
Researchers examined changes to bacteria when faecal matter was exposed to coffee in a petri dish, and by studying the composition of faeces after rats ingested differing concentrations of coffee over three days.
However without further research, the scientists couldn't say whether the bacteria that was suppressed was firmicutes, know as "good" bacteria, or enterobacteria, which are regarded as negative. Development was even lower with 3 percent solution. In a separate study, coffee ingestion was shown to help rats better contract muscles in their lower intestines and colon - two key functions for healthy poops. The research will form the basis for further investigation into whether coffee can be a viable treatment for ileus, or post-operative constipation, in which the intestines quit working after abdominal surgery.