A pair of gut bacteria may cause constipation

"Gut bacteria are crucial to ensuring healthy digestion and defecation. But two species of bacteria may also be the cause of constipation: according to a new study, Bacteroides thetaiotaomicron and Akkermansia muciniphila appear to work in concert to break down colonic mucin, the slimy coating in our colons that keeps our poo moving along. Too little mucin means a drier and more constipation-prone colon."

""What excites me most about this study is that we've identified a specific mechanism by which gut bacteria can cause constipation, says Tomonari Hamaguchi, a lecturer at Nagoya University in Japan and the lead author on the study. He notes that constipation causes some 2.5 million doctor visits every year in the United States."

"In the study, which was published this week in Gut Microbes, the researchers modified one of the bacteria, B. thetaiotaomicron, preventing it from breaking down mucin. They then transplanted it and the other bacterium, A. muciniphila, into mice. Interestingly, the mice's colon mucin stayed intact. And the mice remained regular, with no signs of constipation. The findings indicate that both of the bacteria together, and not just one or the other, pose a threat to mucin."

Constipation can result from low water intake, inadequate fiber, sedentary lifestyle, medications, and microbial activity. Two gut bacteria, Bacteroides thetaiotaomicron and Akkermansia muciniphila, cooperate to degrade colonic mucin, the slimy coating that lubricates stool passage. Reduced mucin leads to a drier colon and higher constipation risk. When B. thetaiotaomicron was modified to prevent mucin degradation and combined with A. muciniphila in mice, colonic mucin remained intact and bowel habits stayed regular, indicating both species together drive mucin loss. Many treatments give temporary relief because microbial mechanisms may remain unaddressed. Human prevalence remains unclear.

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