Lack of fiber leads to intestinal inflammation
Last reviewed: 07.06.2024
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Irritable bowel disease (IBD), which can manifest as ulcerative colitis or Crohn's disease, develops as a result of inflammation in the intestines. Scientists have not yet been able to determine the root cause of this disorder, but a recent study suggests a link between genetics, diet and gut microbiota that may lead to the development of irritable bowel syndrome.
A study published in the journal Cell Host & MicrobeTrusted Source, found that fiber plays an important role in the interaction between gut microbes and the digestive mucosa.
Fiber promotes healthy mucus density and suppresses inflammation. People born without interleukin-10, a cytokine associated with GCD, usually develop GCD in early infancy or childhood.
The present study shows that in interleukin-10-deficient mice, fiber deprivation promotes deterioration of the colonic mucosa, leading to fatal colitis. This suggests that fiber-rich diets may be beneficial for people with irritable bowel syndrome.
How does diet affect irritable bowel syndrome?
It is estimated that about 6 million people worldwide suffer from GCD, and the Centers for Disease Control and Prevention (CDC) says about 3 million people in the United States have the disease. According to a new study, industrialized countries have the highest rates of ICD, and people who immigrate to more industrialized countries and start eating highly processed foods are at higher risk for the disease.
A study published last year in Gastroenterology, the official journal of the American Gastroenterological Association, found that certain types of dietary fiber may actually worsen symptoms of inflammatory bowel disease. In this study, researchers found that non-fermentable dietary β-fructan fibers, which are soluble fibers from fruits and vegetables, trigger an inflammatory response in people with IBS whose bodies cannot break them down.
Some people who develop IBS, especially children, are prescribed a low-fiber, formula-based diet known as exclusive enteral nutrition (EEN), and success in reducing intestinal inflammation has been achieved with this approach.
Fiber does not harm beneficial gut bacteria
The new study used mice that also lacked interleukin-10, and the researchers found that inflammation was much worse on a diet without fiber. The fiber-free diet has been shown to promote the growth of mucin-degrading bacteria that engulf a layer of mucin in the digestive system, reducing the barrier that mucin provides to the intestinal mucosa. Mice that followed a high-fiber diet had significantly less inflammation.
However, when the researchers fed the mice an EEN dietary formula, some of them had less inflammation than those on the fiber-free diet.
The researchers concluded that these mice had more of a fatty acid called isobutyrate, which is produced by fermentation in the gut by "good" bacteria.
Dr. Rudolph Bedford, M.D., a board-certified gastroenterologist at Providence Saint John's Health Center in Santa Monica, California, who was not involved in the study, said that low-fiber diets for people with IHD have not been sufficiently studied for medical purposes.
"Dietary recommendations for patients with HCC vary widely, largely due to a lack of research data," Dr. Bedford said.
Why patients with inflammatory bowel disease may be advised to limit fiber intake
"However, patients with IHD are often advised to limit fiber intake or fiber residues during an active exacerbation to minimize gastrointestinal distress, especially when intestinal strictures are suspected," he said.
A low-fiber diet may be recommended for people with IBS during acute (active) exacerbations, when inflammation in the intestines increases. Fiber is difficult to break down and can therefore aggravate existing irritation of the intestine or its mucous membrane, which can contribute to certain symptoms such as diarrhea, abdominal pain, rectal bleeding, abdominal bloating, or even fever. During exacerbations, it is best to avoid anything that may aggravate existing inflammation in the intestines.
Nevertheless, high-fiber diets have shown promising results in treating HCC in patients in the long term. This means that when patients are not experiencing acute symptoms or exacerbations, it is recommended to consume high-fiber foods to help diversify gut composition, which can positively improve a person's gut pH, permeability, and ability to produce short-chain fatty acids.