Randomised controlled trialindependent cross-checkabstract only checked★ key study I-GUT-04 in-depth review
Wheat fructans, not gluten, cause symptoms
Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity.
Overview
Skodje GI et al.. Gastroenterology 2018 · PMID 29102613 · DOI 10.1053/j.gastro.2017.10.040
In people who felt gluten-sensitive, fructans (wheat sugars) increased bloating and symptoms; gluten did not.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Gluten vs fructan.
- How was the study done?
Crossover RCT.
- How many people, animals or samples were studied?
59.
- What was actually found?
Fructans caused symptoms.
- How large was the observed effect?
GSRS 38.6 vs 34.3.
- What do the results mean in everyday life?
Wheat can cause symptoms via fructans.
- What are the study's limitations?
Small, selected.
- What does it say about Elawady's specific claim?
Partly supports C-GUT-01.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
That bread causes IBS in everyone.
Scientific in-depth review
1. Full reference
- Authors
- Skodje GI et al.
- Journal
- Gastroenterology
- Year
- 2018
- Identifier
- PMID 29102613 DOI 10.1053/j.gastro.2017.10.040
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Do gluten or fructans induce symptoms in self-reported non-coeliac gluten sensitivity?
3. Study design and population
- Study design
- Randomised controlled trial – Randomised double-blind placebo-controlled crossover challenge
- Population
Adults on self-instituted gluten-free diet, coeliac disease excluded
- Country
Norway
- Period
2014–2016
- Sample size
59
- Inclusion and exclusion criteria
Coeliac disease excluded
4. Methods and endpoints
- Exposure / intervention
Gluten 5.7 g or fructans 2.1 g in muesli bars for 7 days
- Comparator
Placebo bars
- Endpoints
GSRS-IBS
- Statistical methods
Linear mixed model
5. Actual results
- Results
GSRS-IBS: gluten 33.1, fructan 38.6, placebo 34.3 (P=.04); bloating 9.3, 11.6, 10.1 (P=.004); fructan > gluten (P=.049); no difference gluten vs placebo.
- Absolute risks
not applicable
- Authors' conclusion
Fructans, not gluten, induce symptoms in self-reported gluten-sensitive individuals.
6. Strengths
- Double-blind crossover
- Separates gluten and fructan
7. Weaknesses
- Small
- Selected population
- Short challenges
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Simplified.
9. Assessment of the statistical interpretation
Modest score differences.
10. Relevance to the specific claim
11. Independent contrary findings
12. Transferability to Germany and Europe
Norwegian; high.
13. Overall methodological judgement
Plausible mechanism for wheat-related symptoms in a subgroup.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | low |
| Precision of results | low |
| Directness | indirect |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Generalisation to IBS populations.