Inulin and gut bacteria in adult human studies
What it found
In nine human studies, inulin supplements most consistently increased Bifidobacterium in the gut.
Other bacteria such as Anaerostipes, Faecalibacterium and Lactobacillus also rose, while Bacteroides fell.
What they found
Studies in people
Bifidobacterium increase
The most consistent change was an increase in Bifidobacterium after inulin supplementation.
Other bacteria changes
Other agreeing results included an increase in the relative abundance of Anaerostipes, Faecalibacterium, and Lactobacillus, and a decrease in the relative abundance of Bacteroides.
Short-chain fatty acids
The human studies did not confirm lab experiments because the changes in bacteria types were not linked to an increase in short-chain fatty acid levels.
What the authors conclude
“The most consistent change was an increase in Bifidobacterium.”
Also in their conclusions
- They say their systematic review assessed the evidence for the effects of inulin supplementation on the human gut microbiome.
- They note that the in vivo studies did not confirm in vitro experiments as the taxonomic alterations were not associated with increase in short-chain fatty acids levels.
How it was done
Inulin is a fermentable fiber that gut bacteria break down into short-chain fatty acids. The authors wanted to understand how inulin changes the human gut microbiome to learn how it works.
They searched four databases for English-language human studies in adults published up to March 2019. Nine original articles were included, most of them randomized, double-blind, placebo-controlled trials. Inulin doses ranged from 5 to 20 grams per day, and three studies combined inulin with oligofructose.
What it can’t tell you
- We summarised it from the abstract only.
- The studies varied a lot in design, doses, and how the microbiome was measured, so the results are not uniform.
- This review can show links between inulin and gut bacteria changes, but it cannot prove that inulin causes those changes.
Who paid
- Authors work at
- Université de Nantes, France; Centre hospitalier universitaire de Nantes, France; Nantes University Hospital, France
The paper
- Title
- The effects of inulin on gut microbial composition: a systematic review of evidence from human studies
- Type
- Systematic review
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Le Bastard Q, Chapelet G, Javaudin F, Lepelletier D, Batard E, Montassier E (2020). The effects of inulin on gut microbial composition: a systematic review of evidence from human studies. European journal of clinical microbiology & infectious diseases. doi:10.1007/s10096-019-03721-wPubMed 31707507DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error