Randomised controlled trialindependent cross-checkabstract checked I-WHT-103 standard review
High-gluten bread looks clumpier in the stomach but empties normally
Effect of bread gluten content on gastrointestinal function: a crossover MRI study on healthy humans.
Overview
Coletta M et al.. Br J Nutr 2016 · PMID 26522233 · DOI 10.1017/S0007114515004183
MRI showed more heterogeneous stomach contents with high-gluten bread, but emptying time and symptoms did not differ.
Does the study support the specific claim? Partly · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
See how gluten content changes digestion.
- How was the study done?
MRI crossover.
- How many people, animals or samples were studied?
12 healthy adults.
- What was actually found?
Clumpier chyme, same emptying.
- How large was the observed effect?
Heterogeneity score 6 vs 3.
- What do the results mean in everyday life?
Some truth in "dough-like" contents, but no blockage.
- What are the study's limitations?
Very small.
- What does it say about Elawady's specific claim?
Partly supports the image of a paste; contradicts the impaired-motility part.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Cannot show harm.
Scientific in-depth review
1. Full reference
- Authors
- Coletta M et al.
- Journal
- Br J Nutr
- Year
- 2016
- Identifier
- PMID 26522233 DOI 10.1017/S0007114515004183
- 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
How does bread gluten content affect gastrointestinal function?
3. Study design and population
- Study design
- Randomised controlled trial – Randomised open-label three-way crossover MRI study
- Population
Healthy adults
- Country
UK (MRC/Department of Health funding)
- Period
not stated in abstract
- Sample size
12
- Inclusion and exclusion criteria
Healthy participants
4. Methods and endpoints
- Exposure / intervention
Normal-gluten and added-gluten bread
- Comparator
Gluten-free bread
- Endpoints
Gastric volumes, chyme heterogeneity, small bowel water, colonic volume and gas, symptoms
- Statistical methods
Repeated-measures comparisons
5. Actual results
- Results
Intragastric chyme heterogeneity score higher with added-gluten bread (6, IQR 0.5) than gluten-free bread (3, IQR 0.5), P=0.003; gastric half-emptying time, symptoms, small-bowel water, colonic volume and gas did not differ. Fasting transverse colon volume higher after gluten-free bread (289 vs 212 vs 179 ml; P=0.02).
- Absolute risks
not reported
- Authors' conclusion
MRI gave mechanistic insights into GI responses to different breads.
6. Strengths
- Objective MRI
7. Weaknesses
- n=12
- Open-label
- Healthy only
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Small open-label crossover.
9. Assessment of the statistical interpretation
Gluten changes how bread chyme looks, but not how fast the stomach empties.
10. Relevance to the specific claim
Partial support: more gluten makes gastric contents more clumpy on MRI; but no slowing of emptying and no symptoms.
11. Independent contrary findings
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Mixed, mechanistic.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | not replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Relevance for reflux patients.