Inulin and gut bacteria across nine studies in adults
What it found
Inulin raised levels of certain gut bacteria, especially Bifidobacterium, across nine studies in adults.
The authors found no matching rise in short-chain fatty acids.
What they found
Studies in people
More Bifidobacterium bacteria
The most consistent finding was a rise in Bifidobacterium after people took inulin.
Other bacteria increased
Anaerostipes, Faecalibacterium, and Lactobacillus also became more common in the gut after inulin supplementation.
Bacteroides decreased
The share of Bacteroides bacteria went down when people took inulin.
Studies in people and animals
Short-chain fatty acids unchanged
Lab experiments predicted more short-chain fatty acids, but studies in living people did not show this rise alongside the bacterial changes.
Other findings
Study designs varied
Three studies combined inulin with oligofructose. Seven used gene-sequencing methods to measure gut bacteria.
What the authors conclude
- They assessed the evidence for how inulin supplements change the human gut microbiome.
- They note that studies in living people did not match lab experiments, because the bacterial shifts did not come with higher short-chain fatty acid levels.
How it was done
Inulin is a fiber that gut bacteria break down into short-chain fatty acids. Earlier work linked it to more frequent bowel movements in people with constipation, so the authors wanted to understand how it changes gut bacteria.
They gathered nine original studies in adult humans looking at how inulin affects gut bacteria. Seven were trials where people were randomly assigned to take inulin or a placebo. Daily amounts ranged from 5 to 20 gr per day.
What it can’t tell you
- We summarised it from the abstract only.
- The studies varied widely in design and daily doses, making it hard to pin down exact effects.
- These studies looked only at gut bacteria, not at whether those changes improve overall health.
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 · animals · lab
- 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 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error