Cohort studyindependent cross-checkabstract checked I-LEG-115 standard review
Legumes and inflammatory bowel disease
Dietary Nut and Legume Intake and Risk of Crohn's Disease and Ulcerative Colitis.
Overview
Lopes EW et al.. Inflamm Bowel Dis 2025 · PMID 40037780 · DOI 10.1093/ibd/izaf032
In 223,283 US adults, eating legumes often was not linked to Crohn's disease or ulcerative colitis.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Test legumes and IBD.
- How was the study done?
Prospective cohorts.
- How many people, animals or samples were studied?
223,283 adults.
- What was actually found?
No association.
- How large was the observed effect?
CD 1.26 (0.78-2.04); UC 0.72 (0.44-1.18).
- What do the results mean in everyday life?
No sign that legumes trigger these immune diseases.
- What are the study's limitations?
Few cases.
- What does it say about Elawady's specific claim?
Contradicts C-LEG-02 indirectly.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
It cannot exclude small effects.
Scientific in-depth review
1. Full reference
- Authors
- Lopes EW et al.
- Journal
- Inflamm Bowel Dis
- Year
- 2025
- Identifier
- PMID 40037780 DOI 10.1093/ibd/izaf032 · PMC12455604
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref works API
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Some authors report industry consulting (AbbVie, Takeda); academic funding.
2. Research question
Are nut and legume intakes associated with risk of Crohn's disease and ulcerative colitis?
3. Study design and population
- Study design
- Cohort study – Prospective cohort analysis (NHS, NHSII, HPFS)
- Population
223,283 US adults without IBD at baseline
- Country
USA
- Period
1986-2017
- Sample size
223,283 (371 CD, 481 UC cases)
- Inclusion and exclusion criteria
Excluded prevalent IBD.
4. Methods and endpoints
- Exposure / intervention
Legume intake (FFQ)
- Comparator
Legumes 0-3 times/month
- Endpoints
Confirmed CD, UC
- Statistical methods
Cox proportional hazards, adjusted
5. Actual results
- Results
Legumes >=4 times/week vs 0-3 times/month: CD aHR 1.26 (95% CI 0.78-2.04; P trend 0.59); UC aHR 0.72 (0.44-1.18; P trend 0.20).
- Absolute risks
Not reported
- Authors' conclusion
Nut and legume intake were not associated with CD or UC risk.
6. Strengths
- Large prospective cohorts
- Record-confirmed outcomes
- Long follow-up
7. Weaknesses
- Few cases; wide CIs
- US diet context
- Abstract only
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Dietary measurement error; residual confounding.
9. Assessment of the statistical interpretation
Wide CIs include modest harm and benefit; no signal either way.
10. Relevance to the specific claim
Immune-mediated bowel disease is the closest outcome studied; no association with legumes (C-LEG-02).
11. Independent contrary findings
None.
12. Transferability to Germany and Europe
Plausibly transferable.
13. Overall methodological judgement
Indirect but direct-outcome evidence of no association.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | indirect |
| Reproducibility | not replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Classic autoimmune diseases (lupus, RA, MS) lack legume-specific cohort data.
15. Linked fact checks
- Legumes, and fava beans in particular, cause autoimmune diseases. – Studies contradicting or limiting the claim