High fibre diet stops gut bacteria eating you

Posted on Wed, 18 Jan 17

A remarkable new study has demonstrated that starving gut bacteria of dietary fibre, their preferred food source, results in them turning against you and digesting your gut.  

To help uncover the mechanism by which low dietary fibre intake leads to poor gastrointestinal health, a research team recently performed a detailed experiment that examined the effects of a low fibre diet on gut bacteria, their activity, and impact on gastrointestinal health.  

They discovered that depriving gut bacteria of fibre results in them turning to a secondary food source, you. 

To understand the details, it helps to understand a little about you gut bacteria first. When you eat you use only a few enzymes (about 17) to digest food. Gut bacteria, on the other hand, produce thousands of enzymes, making them better at adapting to complementary or new food sources. 

Normally, gut bacteria degrade otherwise indigestible fibres in your diet, but this study found that when deprived of fibre they start degrading the protective mucus layer that lines your gut and helps to protect you from invasive and harmful bacteria. In fact, the low-fibre diet promoted expansion and activity of specific colonic mucus-degrading bacteria. 

It was also discovered that the fibre-deprived gut was more susceptible to a deadly infection, and that purified prebiotics were unable to restore the gut barrier, despite improving the balance of gut bacteria. 

This discovery helps uncover the mechanisms by which low-fibre intake could impact gastrointestinal and infectious disease, suggest the investigators. “With this in mind, efforts to find the optimal combinations of natural or prebiotic fiber polysaccharides and the minimum intake required to restore the integrity and resilience of the colonic mucus layer should be paramount,” they stated. 

Reference: 

Desai MS, Seekatz AM, Koropatkin NM, et al. A Dietary Fiber-Deprived Gut Microbiota Degrades the Colonic Mucus Barrier and Enhances Pathogen Susceptibility. Cell. 2016 Nov 17;167(5):1339-1353.e21.