Low fiber intake may trigger inflammatory bowel disease, says study

A study published in the journal Cell Host and Microbe found that fiber plays a significant role in the interplay between gut microbes and the mucus lining of the digestive system.

Fiber promotes the development of healthy mucus thickness and inhibits inflammation. For people who are born without interleukin-10, an IBD-associated cytokine, IBD typically develops in early infancy or childhood. Irritable bowel disorder (IBD), which can manifest as either ulcerative colitis or Crohn’s disease, develops out of inflammation in the gut or digestive tract, leading to a range of sometimes painful issues with digestion. Scientists have not been able to identify the root cause of this disorder yet, but a recent study suggests a connection between genetics, diet, and gut microbiota that could lead to the development of IBD.

The study used mice who also lacked interleukin-10. A fibre-free diet was shown to encourage the growth of mucin-degrading bacteria, which consume the mucus layer in the digestive system, reducing the barrier that the mucus provides for the lining of the gut. The mice who ate a high-fiber diet had significantly less inflammation. However, when researchers fed mice the EEN diet formula, some of them had less inflammation than those with a fibre-free diet.

The findings revealed that healthy gut bacteria play a crucial role in both our immune and digestive systems. Certain beneficial bacteria strengthen our intestinal barrier, preventing harmful substances from entering our gut. Weakness in this barrier, known as "leaky gut," often seen in IBD and IBS patients, can cause inflammation or indicate other gut imbalances. Additionally, these bacteria aid in producing neurotransmitters essential for proper brain function and emotional well-being.

“A low-fiber diet may be recommended for people with IBD during acute (active) flare-ups when the inflammation in their gut intensifies. Fiber can be hard to break down, and can therefore exacerbate existing irritation in the gut or gut lining which can contribute to certain symptoms like diarrhea, stomach pain, rectal bleeding, bloating, or even fever. During flare-ups, it’s best to avoid anything that may add to the existing inflammation in the gut,” said Melanie Murphy Richter, a registered dietitian nutritionist.

Reference:Gabriel Vasconcelos Pereira, Marie Boudaud, Mathis Wolter, Kathryn A. Eaton, Mahesh S. Desai, Eric C. Martens; Opposing diet, microbiome, and metabolite mechanisms regulate inflammatory bowel disease in a genetically susceptible host; Journal: Host cell and Microbe; DOI:https://doi.org/10.1016/j.chom.2024.03.001