Irritable bowel disorder (IBD) affects around 3 million people in the U.S. and is often treated with a low fiber or fiber-free diet during flare-ups. However, a new study suggests that fiber plays a significant role in reducing IBD due to its influence on healthy gut bacteria. Research is ongoing to examine the connection between diet, bacteria, and genetics as a way to decrease the development of IBD. IBD, characterized by inflammation in the gut or digestive tract, can manifest as ulcerative colitis or Crohn’s disease, and its root cause is yet to be identified.
The study published in Cell Host & Microbe revealed that fiber promotes the growth of healthy mucus thickness and prevents inflammation in the gut. People who lack interleukin-10, an IBD-associated cytokine, typically develop IBD early in life. In mice lacking interleukin-10, a fiber-free diet led to the deterioration of the colonic mucus lining, resulting in lethal colitis. This suggests that fiber-rich diets could benefit individuals with IBD. There are approximately 6 million people worldwide with IBD, and industrialized nations have higher rates, with immigrants at risk due to increased consumption of processed foods.
Previous research published in Gastroenterology suggested that some dietary fibers, particularly unfermented dietary β-fructan fibers, could worsen IBD symptoms in individuals who cannot break them down. Some children with IBD are placed on an exclusive enteral nutrition (EEN) diet due to its success in reducing gut inflammation. Although dietary recommendations for IBD patients have varied, limiting fiber during flare-ups to minimize gastrointestinal distress is common. A low-fiber diet may exacerbate gut irritation, leading to symptoms such as diarrhea, stomach pain, and bloating.
The recent study in Cell Host & Microbe found that inflammation was higher in mice on fiber-free diets when interleukin-10 was lacking, prompting the growth of mucin-degrading bacteria that consume the mucus layer in the gut. Conversely, mice on a high fiber diet experienced significantly less inflammation. Additionally, EEN diet-fed mice with higher levels of the fatty acid isobutyrate, produced through gut fermentation by beneficial bacteria, showed reduced inflammation. Despite the success of EEN diets in some cases, there is limited research on the effectiveness of low-fiber diets for individuals with IBD.
A lack of diversity in the gut microbiome can lead to a weakened immune system and increased susceptibility to chronic diseases. Gut health is closely linked to mental health, as certain gut bacteria produce neurotransmitters necessary for proper brain function and emotional well-being. Foods and beverages such as alcohol, processed foods, and high-fructose corn syrup can cause gut inflammation and dysbiosis, exacerbating IBD symptoms. Probiotic-rich foods like kimchi and yogurt, along with healthy sources of fiber from fruits and vegetables, can help feed and maintain beneficial gut bacteria, preventing inflammation and improving overall gut health. Adopting a balanced diet and lifestyle can support the gut microbiome and reduce the risk of chronic diseases associated with dysbiosis.
