Randomised controlled trialindependent cross-checkabstract checked I-LEG-125 standard review

Do beans really cause much gas?

Perceptions of flatulence from bean consumption among adults in 3 feeding studies.

Overview

Winham DM, Hutchins AM. Nutr J 2011 · PMID 22104320 · DOI 10.1186/1475-2891-10-128

Fewer than half of adults noticed more gas when they started eating beans daily, and it eased over time.

Does the study support the specific claim? No · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Assess flatulence from beans.
How was the study done?: Feeding trials.
How many people, animals or samples were studied?: 126 adults.
What was actually found?: <50% more flatulence at first.
How large was the observed effect?: 19% with black-eyed peas.
What do the results mean in everyday life?: Bean gas is usually mild.
What are the study's limitations?: Self-report.
What does it say about Elawady's specific claim?: Contradicts dramatic gas claims.
Do the results apply to Germany and Europe?: Applicable.
What can explicitly not be concluded from this study?: It does not address dizziness or anaemia.

How often do adults perceive increased flatulence and GI discomfort when eating 1/2 cup of beans daily?

Study design: Randomised controlled trial – Secondary analysis of three randomised feeding trials (two crossover, one parallel)
Population: Adults in three bean feeding studies
Country: USA (inferred from reference to US Dietary Guidelines; not explicit)
Period: 8-12 week phases
Sample size: 17 + 29 + 80 participants
Inclusion and exclusion criteria: Trial participants.

Exposure / intervention: 1/2 cup pinto beans, black-eyed peas or baked beans daily
Comparator: Canned carrots or control soup
Endpoints: Perceived flatulence, stool changes, bloating
Statistical methods: Chi-square

Results: Less than 50% reported increased flatulence with pinto or baked beans in the first week; 19% with black-eyed peas; 3-11% reported increased flatulence on control diets.
Absolute risks: Not applicable
Authors' conclusion: Concerns about excessive flatulence from beans may be exaggerated; individual variation exists.

Symptoms common at start, decreased over time (per full study design).

Shows that bean-related gas is common but usually mild and transient (C-LEG-09); relevant to legume intolerance outside IBS (C-LEG-12).

None.

Applicable.

Gas from beans is real but overestimated; no link to other diseases.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	low
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

None.