Inulin and inulin-propionate ester for insulin sensitivity
What it found
In adults with overweight and obesity, 20 g a day of inulin or inulin-propionate ester for 42 days improved insulin sensitivity compared with cellulose.
The two fibres worked in different ways.
What they found
Studies in people
Insulin sensitivity improved
Both inulin and inulin-propionate ester improved insulin resistance compared with cellulose, with no difference between the two. Fasting insulin was lower after both inulin and inulin-propionate ester than after cellulose.
Inflammation and immune markers
Inulin-propionate ester decreased interleukin-8 levels compared with cellulose, while inulin had no impact on the inflammatory markers studied. Inulin-propionate ester also increased IgG levels compared with cellulose.
Gut bacteria changes
Inulin increased Actinobacteria and decreased Clostridia compared with cellulose, and promoted a bifidogenic effect. Inulin-propionate ester caused changes at the species level compared with cellulose.
Plasma metabolome links
Fasting insulin was linked to different plasma metabolites after each supplement. For example, tyrosine and glycine were only associated with fasting insulin after inulin.
Animal and lab studies
Lab test on immune cells
In lab tests, immune cells from healthy people released less interleukin-8 when grown with sodium propionate than with sodium acetate or sodium chloride.
What the authors conclude
“These data demonstrate a distinctive physiological impact of raising colonic propionate delivery in humans, as improvements in insulin sensitivity promoted by IPE and inulin were accompanied with different effects on the plasma metabolome, gut bacterial populations and markers of systemic inflammation.”
Also in their conclusions
- They conclude that raising colonic propionate delivery in humans has a distinctive physiological impact.
- They state that improvements in insulin sensitivity from inulin-propionate ester and inulin were accompanied by different effects on the plasma metabolome, gut bacterial populations and markers of systemic inflammation.
- They suggest that manipulating the colonic fermentation profile of a dietary fibre in favour of propionate promotes selective effects on the mechanisms that contribute to metabolic dysregulation.
How it was done
The authors wanted to understand the mechanisms behind changes in glucose homeostasis when propionate is delivered to the human colon, by analysing gut bacterial composition, plasma metabolome and immune responses.
Twelve non-diabetic adults with overweight and obesity took 20 g a day of inulin-propionate ester, inulin or cellulose for 42 days each, in a random order. At the end of each period, the researchers measured metabolic responses, inflammatory markers and gut bacterial composition.
What it can’t tell you
- This was a small trial with 12 people, so the results may not apply to everyone.
- The study lasted 42 days per supplement, so it cannot show long-term effects.
- The trial cannot show whether these changes would prevent or treat diabetes.
Who paid
- Funding
- Funded by Biotechnology and Biological Sciences Research Council; Medical Research Council; Department of Health (from the PubMed record).
- Conflicts
- Competing interests: A patent application for ’Compounds and their effects on appetite control and insulin sensitivity' surrounding the use of inulin-propionate ester has been filed by GSF and DJM (WO2014020344). None of the other authors reported a conflict of interest related to the study.
- Authors work at
- Imperial College London, UK; Scottish Universities Environmental Research Centre, UK; University of the West of Scotland, UK
The paper
- Title
- Dietary supplementation with inulin-propionate ester or inulin improves insulin sensitivity in adults with overweight and obesity with distinct effects on the gut microbiota, plasma metabolome and systemic inflammatory responses: a randomised cross-over trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Chambers ES, Byrne CS, Morrison DJ, et al (2019). Dietary supplementation with inulin-propionate ester or inulin improves insulin sensitivity in adults with overweight and obesity with distinct effects on the gut microbiota, plasma metabolome and systemic inflammatory responses: a randomised cross-over trial. Gut. doi:10.1136/gutjnl-2019-318424Free full textPubMed 30971437DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error