Meta-analysisindependent cross-checkabstract checked I-WHT-104 standard review
Gluten worsened bloating and fullness in some sensitive patients
Effects of gluten on dyspeptic symptoms: a systematic review and meta-analysis of clinical trials.
Overview
Hosseinian SZ et al.. Nutr Rev 2023 · PMID 37115663 · DOI 10.1093/nutrit/nuad034
In five pooled trials, gluten challenge modestly increased bloating, early fullness and upper abdominal pain.
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?
Check gluten and indigestion.
- How was the study done?
Meta-analysis.
- How many people, animals or samples were studied?
5 RCTs pooled.
- What was actually found?
Modest increase in some symptoms.
- How large was the observed effect?
WMD 0.46-0.91.
- What do the results mean in everyday life?
Some people feel better with less gluten.
- What are the study's limitations?
Few trials, heterogeneous.
- What does it say about Elawady's specific claim?
Partial support for symptoms, not for glue.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Does not apply to everyone.
Scientific in-depth review
1. Full reference
- Authors
- Hosseinian SZ et al.
- Journal
- Nutr Rev
- Year
- 2023
- Identifier
- PMID 37115663 DOI 10.1093/nutrit/nuad034
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Does gluten affect dyspeptic symptoms?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of clinical trials (GRADE)
- Population
Patients in trials of gluten-free diet, low-gluten diet or gluten challenge with dyspeptic symptoms
- Country
International
- Period
Searches to May 2022
- Sample size
27 studies in review (18 RCTs); 5 RCTs meta-analysed
- Inclusion and exclusion criteria
RCTs and non-RCTs on gluten and dyspeptic symptoms
4. Methods and endpoints
- Exposure / intervention
Gluten challenge
- Comparator
Placebo/gluten-free
- Endpoints
Bloating, early satiety, epigastric pain, nausea
- Statistical methods
Random-effects WMD; GRADE
5. Actual results
- Results
Gluten challenge increased bloating (WMD 0.67; 0.37-0.97; I2 81.8%), early satiety (0.91; 0.58-1.23; I2 27.2%) and epigastric pain (0.46; 0.17-0.75; I2 65.8%); not nausea (0.13; -0.17 to 0.43).
- Absolute risks
not reported
- Authors' conclusion
Gluten challenge worsened dyspeptic symptoms; gluten restriction could help; larger RCTs in functional dyspepsia needed.
6. Strengths
- Pooled RCTs
- GRADE
7. Weaknesses
- Only 5 RCTs pooled
- High heterogeneity
- Mixed populations (NCGS, IBS)
- Gluten vehicles may contain fructans
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Few trials; heterogeneity.
9. Assessment of the statistical interpretation
Small absolute symptom differences on mostly 0-10 scales.
10. Relevance to the specific claim
Honest partial support: in selected patients, gluten challenge modestly worsened dyspeptic symptoms; this is about gluten in sensitive groups, not white flour sticking in everyone.
11. Independent contrary findings
I-GRN-101, I-GRN-102 (nocebo).
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Partial support for "indigestion" in a subgroup, not for the mechanism.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | indirect |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Functional dyspepsia RCTs.