PrebioticsDo prebiotics change your gut bacteria?
Short answer
Yes, mainly by raising bifidobacteria, but this does not always improve symptoms. In a 2019 review of 11 trials in functional bowel disorders, prebiotics raised bifidobacteria and did not improve symptoms overall.[1] A 2022 review of trials in healthy adults found more Bifidobacterium, Lactobacillus and Faecalibacterium prausnitzii with inulin-type fructans.[2]
Dose matters: in 132 adults with self-reported constipation, 11 g of GOS raised Bifidobacterium more than 5.5 g.[3] Results are not uniform. A 2025 review of 36 studies of prebiotics, probiotics and synbiotics called the effects on gut bacteria and their products contradictory and inconclusive. Some of its studies found more bifidobacteria with prebiotics.[4]
Sources (4)
- Prebiotics in irritable bowel syndrome and other functional bowel disorders in adults: a systematic review and meta-analysis of randomized controlled trials. Wilson B, Rossi M, Dimidi E, Whelan K Am J Clin Nutr, 2019. PMID 30949662
- The Prebiotic Potential of Inulin-Type Fructans: A Systematic Review. Hughes RL, Alvarado DA, Swanson KS, Holscher HD Adv Nutr, 2022. PMID 34555168
- Prebiotic Galacto-Oligosaccharides Impact Stool Frequency and Fecal Microbiota in Self-Reported Constipated Adults: A Randomized Clinical Trial. Schoemaker MH, Hageman JHJ, Ten Haaf D, Hartog A, Scholtens PAMJ, Boekhorst J, et al. Nutrients, 2022. PMID 35057489
- The Effects of Prebiotic Dietary Fibers, Probiotics, and Synbiotics on Gut Permeability and Immunity: A Systematic Review. Maghsoumi-Norouzabad L, Bagherzadeh-Karimi A, Aliakbari Majd S, Hosseini L, Shahi F Iran J Med Sci, 2025. PMID 40861839
More about prebiotics
What are prebiotics?How long do prebiotics take to work?Which foods contain prebiotics?What are prebiotics used for?Is a synbiotic better than a prebiotic alone?Are prebiotics the same as fiber?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.