Prebiotic fiber refers to a specific class of nondigestible carbohydrates that selectively nourish beneficial gut microbes. Unlike general dietary fiber, prebiotics must meet strict criteria including resistance to digestion, fermentability by gut bacteria, and demonstrated health benefits.
Prebiotic fibers reach the colon intact, where they support bacterial species associated with metabolic health, immune regulation, and gut barrier function.
Common Types of Prebiotic Fibers
• Resistant starch
• Inulin, chicory root, and fructooligosaccharides (FOS)
• Galactooligosaccharides (GOS)
• Select soluble fibers
Each type varies in fermentation rate and tolerance, which is why individualized selection matters.
Health Benefits of Prebiotic Fiber
Research links prebiotic fiber intake to:
• Improved gut microbial diversity
• Increased production of short-chain fatty acids
• Reduced systemic inflammation
• Enhanced insulin sensitivity
How Prebiotic Fiber Differs From Other Fibers
Not all fibers act as prebiotics. Some fibers primarily support stool bulk or transit time but do not meaningfully alter the microbiome. Prebiotic fibers provide a direct substrate for microbial metabolism, creating downstream physiological effects. Read Prebiotic Fiber and Gut Health for more.
References
• Gibson GR et al. Expert consensus on prebiotics. Nat Rev Gastroenterol Hepatol. 2017
• Inoue et al. Dietary fiber supplementation on gut microbiota... Microorganisms. 2025