Researchers say they have cleared up one aspect of how our bowels move that has mystified scientists for, well, forever. 

It isn't all unknown. Segmentation motor activity in the gut that enables absorption of nutrients was described in the late 1800s. But now gastroenterologist Jan Huizinga and a team have learned that of the two types of movement, segmentation motion occurs when not one but two sets of pacemakers interact with each other to create a specific rhythm.

They then work together with nerves and muscle to generate the movement that allows for nutrient absorption. The other type of movement moves the food along.

The discovery was made by Huizinga, a professor of medicine, and colleagues at the Farncombe Family Digestive Health Institute at McMaster University working with investigators of Wuhan University in China and colleagues at the University of Toronto. 

"In the long run, it's simple," said Huizinga. "It's like when a stone is dropped in water, it creates waves or motion that pushes things along, but when a second stone is dropped in the water, the movement changes to up and down, appearing to stay in the same place."

Live tissue c-kit staining (red) of ICC-MP (a), the layer in between ICC-MP and ICC-DMP (b) and ICC-DMP (c) using fluorescence microscopy. Credit: 

The discovery is important as it gives direction for development of drugs or nutrients which will combat disorders when people have diarrhea, constipation, bloating or malabsorption of nutrients from food. With diarrhea, the segmentation activity is too low; in constipation, the same activity is too high and pain related to eating is often caused by abnormal contractions, said Huizinga.

Citation: Jan D. Huizinga, Ji-Hong Chen, Yong Fang Zhu, Andrew Pawelka, Ryan J. McGinn, Berj L. Bardakjian, Sean P. Parsons, Wolfgang A. Kunze, Richard You Wu, Premysl Bercik, Amir Khoshdel, Sifeng Chen, Sheng Yin, Qian Zhang, Yuanjie Yu, Qingmin Gao, Kongling Li, Xinghai Hu, Natalia Zarate, Phillip Collins, Marc Pistilli, Junling Ma, Ruixue Zhang&David Chen, 'The origin of segmentation motor activity in the intestine', Nature Communications 5, Article number: 3326 doi:10.1038/ncomms4326. Source: McMaster University