The amount of fiber in a person’s diet influences a range of important factors, such as weight gain, blood sugar, insulin sensitivity, and colon health. This series of outcomes is based on two studies conducted with mice. The studies were conducted by microbiologists working at the Georgia State University’s Center for Inflammation Immunity & Infection.
Fiber various in terms of different foods, in relation to its form; foods high in fiber include fruits, legumes, vegetables, and whole grains. Diets that are high in fats and sugars but low in fiber are connected to an increased risk of inflammatory bowel diseases, weight gain, and diabetes.
Both studies looked at fiber and the impact upon the microbiome of the human gut. The human microbiome (or human microbiota) is the aggregate of microorganisms, a microbiome that resides on the surface and in deep layers of skin, in the saliva and oral mucosa, in the conjunctiva, and in the gastrointestinal tracts.
With the research, scientists began feeding a group of mice a diet that was extremely low in fiber. These diets rapidly led to weight gain, high blood sugar, and insulin resistance in the mice. The first study shows that found that mice developed problems with the protective mucus layer in the colon after just 3-7 days of eating the low-fiber diet. This was linked to bacteria encroaching upon the epithelial cells of the colon.
The second study found that the colons of mice on the low-fiber diet shrank significantly in thickness. This was in conjunction with a decline with the levels of beneficial gut bacteria in conjunction with a rise of potential harmful bacterial species.
Commenting on the first research round, lead scientist Dr. Andrew Gewirtz explained the implications of the research: “Once the mechanism is understood, it can be exploited in different ways to promote health”; and emphasizing the importance: “This will allow ways to modify diets to maximize those benefits.”
The negative effects can be reversed. Both studies showed how a transplant of gut bacteria from a healthy mouse could undo some of the harmful changes to the colon mucus layer. This paves the way for transplants of beneficial bacteria to people, although ill-health conditions are best addressed by increasing fiber in the diet.
Both studies have been reported to the journal Cell Host & Microbe. Study one is titled “Bifidobacteria or Fiber Protects against Diet-Induced Microbiota-Mediated Colonic Mucus Deterioration”; whereas the second research paper is headed “Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health.”