Evidence map›Paper›PMID 41611088›Full record

SynthesisThe American journal of clinical nutrition2026

Fiber intake and laxation in people with normal bowel function: a systematic review.

Ethan M Balk, Elyse Couch, Htun Ja Mai, Yunan Chen, Gaelen P Adam, Ghid Kanaan, Eduardo L Caputo, Thomas A Trikalinos, Georgina Williams, Kerith Duncanson and 2 more

Abstract readSystematic Review
In one paragraph

Synthesis in The American journal of clinical nutrition, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors.

Ethan M BalkCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States. Electronic address: ethan_balk@brown.edu.
Elyse CouchCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Htun Ja MaiCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Yunan ChenCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Gaelen P AdamCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Ghid KanaanCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Eduardo L CaputoCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Thomas A TrikalinosCenter for Evidence Synthesis in Health, Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, United States.
Georgina WilliamsHunter Medical Research Institute, New Lambton Heights, Australia.
Kerith DuncansonHunter Medical Research Institute, New Lambton Heights, Australia.
Nicholas J TalleySchool of Medicine and Public Health, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia.
Alice H LichtensteinHuman Nutrition Research Center on Aging, Tufts University, Boston, MA, United States.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundOptimal evidence-based dietary recommendations for dietary fiber have not been established.

objectivesThis study aims to conduct a systematic review of fiber and gut motility (laxation) in noninfants with normal bowel function.

methodsWe searched PubMed, Embase, and CINAHL from inception through 4 March, 2025, and existing systematic review reference lists. We included randomized controlled trials (RCTs) in the general population without bowel dysfunction that compared fiber amounts or types and assessed stool consistency, fecal weight, fecal frequency, or gut transit time. We categorized fibers according to their solubility, viscosity, and fermentability and performed hierarchical Bayesian regression models and spline analyses across reported total and added fiber intake doses, with subanalyses by fiber type. We assessed study risk of bias and strength of evidence (SoE).

resultsWe identified 113 eligible trials, with low or moderate risk of bias. Models provided moderate SoE that increasing fiber intake (per g/d total fiber) yields softening stool consistency [0.013 units, 95% credible interval (CrI): 0.009, 0.016 on the Bristol Stool Scale], increasing total fecal weight (1.76 g/d, 95% CrI: 1.58, 1.94) and dry fecal weight (0.47 g/d, 95% CrI: 0.42, 0.51), increasing fecal frequency (0.053 additional bowel movements/wk, 95% CrI: 0.042, 0.065), and shortening gut transit times (-0.24 h, 95% CrI: -0.36, -0.12). Associations between fiber intake and outcomes varied across fiber doses and type. Low-solubility and low-fermentability fibers had the strongest associations with laxation outcomes, with low to medium SoE. However, findings are indirect, based on models, and there is insufficient evidence in specific subpopulations.

conclusionsRCTs support small to modest effects of dietary fiber on laxation in generally healthy people with normal bowel function. Low-solubility and low-fermentability fibers yielded the strongest effects. Future studies should better characterize fiber properties, assess wider ranges of fiber doses, and comprehensively report participants' total and background fiber intake. This study was registered at PROSPERO as CRD42024522380.

Indexed as

Dietary FiberGastrointestinal MotilityLaxativesAdultDefecationFecesGastrointestinal TransitHumansRandomized Controlled Trials as TopicDietary FiberLaxativesdietary fiberfiber fermentabilityfiber solubilityfiber viscositygastrointestinal functionhierarchical Bayesian regression modelinglaxationmeta-analysis

Identifiers

PMID41611088
PMCPMC12975388

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.