Supplements · Metabolic & Cardiometabolic
inulin-type fructans increases GLP-1
In plain terms: Does inulin fibre boost the appetite-suppressing gut hormone GLP-1?
Part of: 🧪 inulin-type fructans
Probably not in people. Human trials that measured this hormone found no rise with inulin, and the support comes mostly from rat studies and one small, low-quality trial.
🧭 Read this score with how it was built in mindWe re-read the papers behind these claims and corrected how each one is counted
Trials whose primary endpoint was GLP-1 and found no rise had been filed as neutral; under the clarified rule a clean null counts against the claim. Three rows that never measured GLP-1 at all were removed. The direction changed because the record did.
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
The evidence leans against this. The human trials that actually measured GLP-1 found no rise: 16 g/d inulin-type fructans for 6 weeks in T2D, with GLP-1 as the primary endpoint, did not raise the meal GLP-1 response (birkeland-2021); 21 g/d oligofructose for 12 weeks in overweight adults did not affect active GLP-1 (PMID 19386741); and a single 25 g dose in severe obesity did no better than…
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Birkeland E, Gharagozlian S, Birkeland KI, Holm OKS, Thorsby PM, Aas AM 2021 · J Nutr Sci | RCT | tested-null | moderate | Secondary-outcome report of the Oslo ITF crossover RCT (35 randomised, 29 analysed, T2D; 16 g/d inulin-type fructans vs maltodextrin, 6 wk each, 4-wk washout): acylated ghrelin P=0.71; total PYY response rose after CONTROL (+11.1 pg/ml) and not after ITF (-0.3; P=0.013); hunger, satiety, fullness and energy intake unchanged. GLP-1, the claim's object, was not measured in this paper; it cites its own parent report that ITF 'did not positively affect concentrations of GLP-1' (that report is counted as ev-birkeland-2021). PYY is a co-secreted L-cell hormone, a surrogate at most. Off-scope for GLP-1, and a duplicate population of the parent trial. |
| Hamilton CC, Bomhof MR 2023 · Nutrients | RCT | mixed | low | Oligofructose-enriched inulin acutely modified post-exercise appetite markers in line with enhanced satiety-hormone (GLP-1/PYY) release. |
| de Fátima Laureano Martins J, Souza-Silva TG, Paula HAA, Rafael VDC, Sartori SSR, Ferreira CLLF 2022 · Life Sci | animal | supports | low | fructan-rich yacon increased GLP-1 (rat) |
| Belobrajdic DP, Jenkins CLD, Christophersen CT, Bird AR 2019 · European J Nutrition | animal | supports | moderate | Cereal inulin-type fructans altered intestinal fermentation, reduced adiposity and increased SCFA, the fermentation route driving colonic GLP-1. |
| Parnell JA, Reimer RA 2012 · British J Nutrition | animal | supports | moderate | Inulin/oligofructose dose-dependently increased satiety hormones (GLP-1, PYY) and altered microbiota in lean and obese rats. |
| Steinert RE, Mueller M, Serra M, Lehner-Sigrist S, Frost G, Gero D, Gerber PA, Bueter M 2024 · Nutr Diabetes | RCT | contradicts | low | Randomized crossover pilot, n=8 patients with severe obesity (BMI 41.5, fasting glucose 5.8 mmol/L; not a T2D sample) studied before and ~8 months after RYGB; single dose 25 g oligofructose-enriched inulin vs maltodextrin in orange juice, 5-h sampling. Clean null for inulin vs maltodextrin on GLP-1: 'Before surgery, there was no effect of inulin or MDX on plasma GLP-1 or PYY concentrations'; after surgery the 30-min GLP-1 rise occurred with both drinks and 'The early-phase hormonal responses after surgery were comparable between inulin and MDX'; authors: 'we also failed to observe significant effects of inulin on GLP-1 and PYY release'. No between-arm estimate or interval reported; no trend toward inulin described. Small n, no power analysis; acute single dose, not the chronic T2D setting of the claim's scope. |
| Cani PD, Joly E, Horsmans Y, Delzenne NM 2006 · Eur J Clin Nutr | RCT | supports | moderate | Single-blind crossover pilot, 10 healthy adults, 16 g/d oligofructose vs dextrine maltose for 2 weeks each. 'Energy intake, hunger, satiety, fullness and prospective food consumption were assessed'; energy intake at breakfast and lunch lower (P=0.01, 0.03); 'Total energy intake per day is 5% lower during OFS'. The gut-peptide rationale comes from rats ('in rats increases satietogenic gut peptides'); GLP-1 was not measured - off-scope. |
| Parnell JA, Reimer RA 2009 · Am J Clin Nutr | RCT | contradicts | high | Double-blind placebo-controlled RCT, n=48 overweight/obese adults, 21 g/d oligofructose vs maltodextrin, 12 wk, meal-tolerance-test hormone AUCs (abstract-grade). On the claim's object: 'Oligofructose supplementation did not affect plasma active glucagon-like peptide 1 secretion.' (estimate/CI not given in abstract). Other gut hormones did move - ghrelin AUC lower (P = 0.004), PYY AUC higher (P = 0.03) - but those are off-object for a GLP-1 claim. Null on GLP-1 = contradicts. |
| Kellow NJ, Coughlan MT, Reid CM 2014 · British J Nutrition | meta-analysis | mixed | moderate | Systematic review of prebiotic RCTs: some trials show raised GLP-1/PYY and improved metabolism, but effects on gut hormones were inconsistent across studies. |
| Birkeland E, Gharagozlian S, Gulseth HL, Birkeland KI, Hartmann B, Holst JJ, Holst R, Aas AM 2021 · Diabet Med | RCT | contradicts | high | Double-blind crossover RCT, 29 adults with T2D, 16 g/d inulin-type fructans vs maltodextrin for 6 weeks each; 'The primary end point was changes in the GLP-1 response'. 'Differences between and within the two treatments in estimated area under the curves were not significant. Yet, the predicted means for meal-induced GLP-1 response in plasma showed a 4.8% decline after the prebiotic treatment and an 8.6% increase after the control treatment (difference in changes between the treatments, p < 0.001).' Clean null pointing away from a rise - contradicts. |
| Darzi J, Frost GS, Swann JR, Costabile A, Robertson MD 2016 · Appetite | RCT | contradicts | moderate | Single-blind crossover, 13 healthy adults, '25.5 g/d l-rhamnose, 22.4 g/d inulin or no supplement' after a 6-d run-in. Assessed: 'qualitative appetite, breath hydrogen, and plasma glucose, insulin, triglycerides and non-esterified fatty acids'. Result: 'neither l-rhamnose or inulin influenced appetite'; insulin lower only for L-rhamnose (P = 0.023). GLP-1 not measured - off-scope for a GLP-1 claim. |
| Salmean YA 2017 · Food Nutr Res | RCT | tested-null | low | RCT, 36 completers (young women), 16 g/d ITF vs placebo drink for 7 days: 'appetite sensations were assessed using visual analogue scale (VAS) along with food intake'; lunch food energy 453 ± 47 vs 571 ± 39 kcal (p = 0.031), total lunch energy p = 0.056. GLP-1 not measured - off-scope. |
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