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Cited by 683Gut microbiota and healthMicrobial Metabolites in Food BiotechnologyFood composition and properties

Dietary fiber intervention on gut microbiota composition in healthy adults: a systematic review and meta-analysis

Open access
So, Daniel, Whelan, Kevin, Rossi, Megan, Morrison, Mark, Holtmann, Gerald, Kelly, Jaimon T, Shanahan, Erin R, Staudacher, Heidi M +1 more·2018·The American Journal of Clinical Nutrition
DOI 10.1093/ajcn/nqy041
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Abstract

Background Dysfunction of the gut microbiota is frequently reported as a manifestation of chronic diseases, and therefore presents as a modifiable risk factor in their development. Diet is a major regulator of the gut microbiota, and certain types of dietary fiber may modify bacterial numbers and metabolism, including short-chain fatty acid (SCFA) generation.Objective A systematic review and meta-analysis were undertaken to assess the effect of dietary fiber interventions on gut microbiota composition in healthy adults.Design A systematic search was conducted across MEDLINE, EMBASE, CENTRAL, and CINAHL for randomized controlled trials using culture and/or molecular microbiological techniques evaluating the effect of fiber intervention on gut microbiota composition in healthy adults. Meta-analyses via a random-effects model were performed on alpha diversity, prespecified bacterial abundances including Bifidobacterium and Lactobacillus spp., and fecal SCFA concentrations comparing dietary fiber interventions with placebo/low-fiber comparators.Results A total of 64 studies involving 2099 participants were included. Dietary fiber intervention resulted in higher abundance of Bifidobacterium spp. (standardized mean difference (SMD): 0.64; 95% CI: 0.42, 0.86; P < 0.00001) and Lactobacillus spp. (SMD: 0.22; 0.03, 0.41; P = 0.02) as well as fecal butyrate concentration (SMD: 0.24; 0.00, 0.47; P = 0.05) compared with placebo/low-fiber comparators. Subgroup analysis revealed that fructans and galacto-oligosaccharides led to significantly greater abundance of both Bifidobacterium spp. and Lactobacillus spp. compared with comparators (P < 0.00001 and P = 0.002, respectively). No differences in effect were found between fiber intervention and comparators for α-diversity, abundances of other prespecified bacteria, or other SCFA concentrations.Conclusions Dietary fiber intervention, particularly involving fructans and galacto-oligosaccharides, leads to higher fecal abundance of Bifidobacterium and Lactobacillus spp. but does not affect α-diversity. Further research is required to better understand the role of individual fiber types on the growth of microbes and the overall gut microbial community. This review was registered at PROSPERO as CRD42016053101.

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Crossref · 10.1093/ajcn/nqy041

Cites

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Claims the paper makes

0 of 31 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    General fiber interventions did not differ from comparators in Bifidobacterium spp. abundance (SMD 0.25; 95% CI -0.16, 0.65; P = 0.24).

    “However, there was no difference in effect between the general fiber subgroup and comparators (SMD: 0.25; 95% CI: -0.16, 0.65; P = 0.24, I 2 = 86%).”
    Quote in the paperSubstantial claim
  • Findingown data

    Dietary fiber increased Bifidobacterium spp. abundance relative to comparators at doses ≤5 g/d (SMD 0.51; 95% CI 0.18, 0.84; P = 0.003).

    “Subgroup analysis of dose-response showed dietary fiber led to significantly higher Bifidobacterium spp.abundance compared with placebo/low-fiber comparators at all predefined dosages (≤5 g/d fiber SMD: 0.51; 95% CI: 0.18, 0.84; P = 0.003, I 2 = 70%; 5-10 g/d SMD: 0.48; 95% CI: 0.13, 0.83; P = 0.007, I 2 = 87%; >10 g/d SMD: 0.85; 95% CI: 0.45, 1.25; P < 0.00001, I 2 = 85%).”
    Quote in the paperSubstantial claim
  • Findingcitation

    In supplement trials of accepted prebiotics, inulin supplementation resulted in higher Bifidobacterium spp. abundance than placebo at the end of intervention.

    “In the supplement trials of accepted prebiotics, a significantly higher Bifidobacterium spp.abundance was reported after supplementation involving inulin (115) and human milk oligosaccharides (HMO) (62) compared with placebo at the end of intervention, whereas a significant within-group increase from baseline was detected after 10 g/d inulin supplementation (95).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [115] Blædel, 2016, A randomised, controlled, crossover study of the effect of diet on angiopoietin-like protein 4 (ANGPTL4) through modification of the gut microbiome, J Nutr Sci source

      Not checked in the free run.

  • Findingown data

    Dietary fiber increased Bifidobacterium spp. abundance relative to comparators at doses of 5-10 g/d (SMD 0.48; 95% CI 0.13, 0.83; P = 0.007).

    “Subgroup analysis of dose-response showed dietary fiber led to significantly higher Bifidobacterium spp.abundance compared with placebo/low-fiber comparators at all predefined dosages (≤5 g/d fiber SMD: 0.51; 95% CI: 0.18, 0.84; P = 0.003, I 2 = 70%; 5-10 g/d SMD: 0.48; 95% CI: 0.13, 0.83; P = 0.007, I 2 = 87%; >10 g/d SMD: 0.85; 95% CI: 0.45, 1.25; P < 0.00001, I 2 = 85%).”
    Quote in the paperSubstantial claim
  • Findingown data

    Food interventions did not differ from comparators in Bifidobacterium spp. abundance (SMD 0.20; 95% CI -0.36, 0.76; P = 0.49).

    “However, subgroup analysis showed fiber interventions delivered through supplements resulted in a significantly higher Bifidobacterium spp.abundance compared with placebo/lowfiber controls (SMD: 0.75; 95% CI: 0.52, 0.98; P < 0.00001, I 2 = 83%), whereas no differences were found between food interventions and comparators (SMD: 0.20; 95% CI: -0.36, 0.76; P = 0.49, I 2 = 88%), although considerable”
    Quote in the paperSubstantial claim
  • May combine two claims. 35
  • Classified as probably not a substantial claim. 15

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    Findingown data

    Intervention doses ranged from 1.2 to 50 g/d, and treatment periods ranged from 5 days to 3 months, with a median of 3 weeks.

    “Intervention doses ranged from 1.2 g/d to 50 g/d and treatment periods ranged from 5 d to 3 mo, with a median length of 3 wk.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Outcome data from 58 studies were suitable for meta-analysis, and 13 studies could not be pooled.

    “Overall, outcome data from 58 studies were suitable for meta-analysis; results from the following studies were unable to be statistically pooled and are presented narratively under their respective subheadings (59, 62, 69, 77-79, 83, 93, 95, 97, 101, 113, 115).”
    Quote in the paperSubstantial claim

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    Findingcitation

    A flaxseed mucilage trial showed a significant within-group reduction in α-diversity from baseline, but no between-group comparison was reported.

    “A significant reduction in the αdiversity of fecal microbiota from baseline was detected in a trial involving flaxseed mucilage, measured by both the exponential of Shannon diversity index (-38,010; 95% CI: -64,473, -11,546; P = 0.007) as well as Simpson's inverse index (-17,515; 95% CI: -30,992, -4038; P = 0.014), although a between-group comparison was not reported (59).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [59] Brahe, 2015, Dietary modulation of the gut microbiota – a randomised controlled trial in obese postmenopausal women, Br J Nutr source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Fiber intervention led to significantly higher fecal concentrations of total SCFA, acetate, and butyrate compared with comparators when expressed per wet weight of feces.

    “Fiber intervention led to significantly higher fecal concentrations of total SCFA, acetate, and butyrate compared with comparators when expressed per wet weight of feces.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Dietary fiber had no effect on total SCFA concentration compared with placebo or low-fiber comparators (SMD 0.11, 95% CI -0.05 to 0.27, P=0.19), with similar effects across studies (I2=0%).

    “Dietary fiber had no effect on total SCFA concentration compared with placebo/low-fiber comparators (SMD: 0.11; 95% CI: -0.05, 0.27; P = 0.19), with similar intervention effects across studies (I 2 = 0%).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Heterogeneity in the Lactobacillus meta-analysis was considerable (I2=80%) and was skewed by a single outlier study.

    “However, heterogeneity was considerable (I 2 = 80%), and was skewed by results from a single outlier study (66) (4.70; 95% CI: 3.69, 5.70).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    No differences in fecal propionate between fiber intervention and comparators (SMD -0.01, 95% CI -0.20 to 0.22, P=0.95), with moderate heterogeneity (I2=61%).

    “No differences were found between fecal propionate and comparators (SMD: -0.01; 95% CI: -0.20, 0.22; P = 0.95), with moderate heterogeneity detected (I 2 = 61%).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Alpha-diversity was measured in 13 studies involving 393 participants.

    “Alpha-diversity was measured in 13 studies involving 393 participants (49,59,64,72,75,77,79,80,83,88,93,97,101).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Dietary fiber had no effect on Roseburia spp. abundance compared with placebo or low-fiber comparators (SMD 0.33, 95% CI -0.14 to 0.80, P=0.17), with substantial heterogeneity (I2=70%).

    “Dietary fiber had no effect on Roseburia spp.abundance compared with placebo/low-fiber comparators (SMD: 0.33; 95% CI: -0.14, 0.80; P = 0.17) although substantial heterogeneity was detected (I 2 = 70%) (Figure 4).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Lactobacillus spp. abundance was measured in 28 studies involving 867 participants.

    “Lactobacillus spp.abundance was measured in 28 studies involving 867 participants.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Of the included studies, 29 were parallel RCTs and 35 were crossover RCTs.

    “Of these 64 studies, 29 were parallel RCTs (52-80) and 35 were crossover RCTs .”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    After excluding the outlier study, the effect on Lactobacillus abundance remained significant but smaller (SMD 0.22, 95% CI 0.03-0.41, P=0.02) with lower heterogeneity (I2=49%).

    “A sensitivity analysis excluding this study produced a more homogeneous study population (I 2 = 49%), with a modest impact on the result (SMD: 0.22; 95% CI: 0.03, 0.41; P = 0.02) (Figure 3).”
    Quote in the paperSubstantial claim

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    Findingown data

    No difference in fecal acetate after fiber intervention compared with placebo or low-fiber comparators (SMD 0.28, 95% CI -0.08 to 0.63, P=0.13), with substantial heterogeneity (I2=86).

    “There was no difference in fecal acetate after fiber intervention compared with placebo/low-fiber comparators (SMD: 0.28; 95% CI: -0.08, 0.63; P = 0.13), with substantial heterogeneity between studies (I 2 = 86).”
    Quote in the paperSubstantial claim

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    Findingown data

    No difference between dietary fiber and placebo or low-fiber comparators for F. prausnitzii abundance (SMD 0.14, 95% CI -0.12 to 0.39, P=0.29), with substantial heterogeneity (I2=68%).

    “There was no difference between dietary fiber and placebo/low-fiber comparators for F. prausnitzii abundance (SMD: 0.14; 95% CI: -0.12, 0.39; P = 0.29), with substantial heterogeneity between studies (I 2 = 68%) (Figure 4).”
    Quote in the paperSubstantial claim

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    Findingown data

    Bifidobacterium spp. abundance was reported in 59 studies including 1896 participants, and 51 trials with 1629 participants provided data suitable for meta-analysis.

    “A total of 59 studies including 1896 participants reported the effect of dietary fiber on Bifidobacterium spp.abundance and, of these, 51 trials (1629 participants) reported data in a form suitable for meta-analysis (53-58, 60, 61, 63-68, 70, 71, 73-76, 81, 82, 84-94, 96-112, 114).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Dietary fiber did not affect E. rectale abundance compared with placebo or low-fiber comparators (SMD -0.26, 95% CI -1.20 to 0.67, P=0.58), with substantial heterogeneity (I2=75%).

    “Dietary fiber did not affect E. rectale abundance compared with placebo/low-fiber comparators (SMD: -0.26; 95% CI: -1.20, 0.67; P = 0.58) and substantial heterogeneity was detected (I 2 = 75%) (Figure 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    This systematic review and meta-analysis found dietary fiber intervention had no effect on gut microbiota diversity but increased Bifidobacterium and Lactobacillus abundance and fecal butyrate concentration in healthy adults.

    “This systematic review and meta-analysis found dietary fiber intervention had no effect on the diversity of the gut microbiota but did increase abundance of Bifidobacterium and Lactobacillus spp. as well as fecal butyrate concentration in healthy adults.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Dietary fiber had no effect on R. bromii abundance compared with placebo or low-fiber comparators (SMD 0.15, 95% CI -0.15 to 0.45, P=0.33), with no heterogeneity (I2=0%).

    “Dietary fiber had no effect on R. bromii abundance compared with placebo/low-fiber comparators (SMD: 0.15; 95% CI: -0.15, 0.45; P = 0.33), with no heterogeneity detected (I 2 = 0%) (Figure 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Fecal butyrate was significantly higher after fiber intervention compared with placebo or low-fiber comparators (SMD 0.24, 95% CI 0.00 to 0.47, P=0.05), with considerable heterogeneity (I2=70%).

    “Fecal butyrate was significantly higher after fiber intervention compared with placebo/low-fiber comparators (SMD: 0.24; 95% CI: 0.00, 0.47; P = 0.05), although considerable heterogeneity was present (I 2 = 70%).”
    Quote in the paperSubstantial claim

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    Findingown data

    The review included 64 primary studies with 2099 participants.

    “The 64 included primary studies analyzed a total of 2099 participants.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    The Chao1 index was used in two studies, and neither reported a significant difference in α-diversity between fiber intervention and placebo or low-fiber control.

    “The Chao1 index was used to report α-diversity in 2 studies, although there were insufficient data available, precluding meta-analysis.Neither trial reported significant differences between fiber intervention and placebo or low-fiber control (49, 83).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [49] Hooda, 2012, 454 pyrosequencing reveals a shift in fecal microbiota of healthy adult men consuming polydextrose or soluble corn fiber, J Nutr source

      Not checked in the free run.

    • cites [83] Baer, 2014, The metabolizable energy of dietary resistant maltodextrin is variable and alters fecal microbiota composition in adult men, J Nutr source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Diversity, other bacterial groups, and other SCFAs were not significantly different compared with controls after fiber intervention.

    “Although the diversity of the gut microbiota, abundances of other commonly measured bacterial groups, and concentrations of other fecal SCFAs were not significantly different compared with controls after dietary fiber intervention, it is worth noting that a short-term increase in fiber intake does not appear to be rate-limiting to these outcomes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Dietary fiber intervention leads to higher abundance of fecal Bifidobacterium and Lactobacillus spp., and higher fecal butyrate concentration compared with placebo or low-fiber comparators.

    “Dietary fiber intervention leads to a higher abundance of fecal Bifidobacterium and Lactobacillus spp., as well as higher fecal concentration of butyrate compared with placebo/low-fiber comparators.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Candidate prebiotic interventions produced significant effects on Bifidobacterium but not Lactobacillus abundance.

    “However, candidate prebiotic interventions produced different effects on the abundance of these 2 genera, with significant effects demonstrated for Bifidobacterium but not Lactobacillus spp.”
    Quote in the paperSubstantial claim

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    Findingreasoning

    Parallel design studies demonstrated stronger intervention effects and greater heterogeneity compared with crossover for several outcomes.

    “There were differences in intervention effects based on trial design, with parallel design studies demonstrating stronger intervention effects and greater statistical heterogeneity compared with crossover design studies for several outcomes.”
    Quote in the paperNot a substantial claim

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    Findingown data

    Accepted prebiotic fibers had an effect on both Bifidobacterium and Lactobacillus, whereas candidate prebiotic fibers had an effect on Bifidobacterium but not Lactobacillus.

    “Accepted prebiotic fibers had an effect on the abundances of both Bifidobacterium and Lactobacillus spp.whereas candidate prebiotic fibers had an effect on Bifidobacterium spp.abundance but not Lactobacillus spp.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Bifidobacterium and Lactobacillus spp. are more abundant in healthy states than in disease states.

    “Specific bacteria shown to be more abundant in health compared with disease states include Bifidobacterium and Lactobacillus spp.(2,7,14)”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [2] Marchesi, 2016, The gut microbiota and host health: a new clinical frontier, Gut source

      Not checked in the free run.

    • cites [7] Clemente, 2012, The impact of the gut microbiota on human health: an integrative view, Cell source

      Not checked in the free run.

    • cites [14] Tojo, 2014, Intestinal microbiota in health and disease: role of bifidobacteria in gut homeostasis, World J Gastroenterol source

      Not checked in the free run.

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    Premisecitation

    Fermentable dietary fibers act as substrates for colonic microbes, stimulating growth of specific organisms and producing metabolites including SCFAs.

    “Fibers with fermentable characteristics are substrates for the microbial population in the colon, stimulating growth of specific organisms and leading to production of various metabolites including SCFA (19,29,31).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [19] Flint, 2017, The impact of nutrition on intestinal bacterial communities, Curr Opin Microbiol source

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    • cites [29] Holscher, 2017, Dietary fiber and prebiotics and the gastrointestinal microbiota, Gut Microbes source

      Not checked in the free run.

    • cites [31] Wong, 2006, Colonic health: fermentation and short chain fatty acids, J Clin Gastroenterol source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Two review authors screened articles in a blinded, standardized manner, resolving disagreements by consensus or a third reviewer.

    “Two review authors (DS and HMS) screened articles in a blinded, standardized manner, with disagreements in judgment resolved by consensus or a third reviewer (KLC).”
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    Study design and conductnone given

    Two reviewers independently extracted data from eligible studies.

    “Two reviewers (DS and HMS) independently extracted the data from eligible studies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    Funnel plots were generated for outcomes with at least 10 studies, and reporting bias was assessed by funnel plot asymmetry.

    “Funnel plots were generated for outcomes in which ≥10 studies were included in meta-analysis (48) and reporting bias was detected by assessment of funnel plot asymmetry by visual inspection.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] Sterne, 2008, Addressing reporting biases, Cochrane handbook for systematic reviews of interventions source

      Not checked in the free run.

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    Study design and conductown data

    The review methods were prespecified and documented in a PROSPERO protocol (CRD42016053101).

    “The methods including the eligibility criteria, search strategy, extraction process, and analysis were prespecified and documented in a protocol that was published in the PROSPERO as CRD42016053101: http://www.crd.york. ac.uk/PROSPERO/display_record.asp?ID=CRD42016053101.”
    Quote in the paperNot a substantial claim

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    Premisecitation

    Some fibers are classified as prebiotic when they are selectively utilized by host microorganisms and confer a health benefit.

    “Indeed, some fibers can be further classified as “prebiotic” (e.g., fructans) if they have been shown to be selectively utilized by host microorganisms conferring a health benefit (32).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] Gibson, 2017, Expert consensus document: the International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics, Nat Rev Gastroenterol Hepatol source

      Not checked in the free run.

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    Study design and conductcitation

    Risk of bias was independently assessed by two reviewers using Cochrane methodology.

    “Risk of bias was independently assessed by 2 reviewers (DS and HMS) using Cochrane methodology (45).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [45] Higgins, 2008, Assessing risk of bias in included studies, Cochrane handbook for systematic reviews of interventions source

      Not checked in the free run.

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    Study design and conductown data

    Visual inspection of funnel plots found no evidence of asymmetry, indicating reporting bias was unlikely.

    “Visual inspection found no evidence of funnel plot asymmetry, indicating reporting bias was unlikely (Supplemental Figures 234567).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Controlled feeding studies lasting 4 d to 3 wk found no effect on microbial diversity despite significant changes in fiber intake.

    “For instance, controlled feeding studies lasting 4 d to 3 wk found that despite significant changes to fiber intake, there was no effect on microbial diversity (35)(36)(37).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites (35)(36)(37)

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The systematic review was conducted according to PRISMA and Cochrane Handbook guidelines.

    “This systematic review was conducted in line with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement (41), and the guidelines of the Cochrane Handbook for Systematic Reviews and Interventions (42).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [41] Moher, 2015, Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement, Systematic Reviews source

      Not checked in the free run.

    • cites [42] Higgins, 2011, Cochrane handbook for systematic reviews of interventions, Cochrane handbook for systematic reviews of interventions

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    Random sequence generation and allocation concealment were adequately described by 26% and 16% of studies, respectively.

    “Random sequence generation and allocation concealment were adequately described by 26% (59-62, 70-72, 77, 79, 80, 84, 86, 94, 103, 113-115) and 16% (59,61,62,70,77,79,80,86,94,115) of studies, respectively.”
    Quote in the paperNot a substantial claim

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    Interpretationreasoning

    The totality of findings, including that microbial diversity was not compromised, support favorable effects of dietary fiber on gut microbiota.

    “Therefore, the totality of findings here, including that microbial diversity was not compromised, support the favorable effects of dietary fiber on the gut microbiota.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    These results further support favorable effects of dietary fiber and contribute to understanding its effect on gut microbiota.

    “These results further support the favorable effects of dietary fiber and contribute to our understanding of its effect on the gut microbiota.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    This is the first systematic review and meta-analysis to assess the effect of dietary fiber intervention on gut microbiota composition.

    “This study is the first systematic review and meta-analysis to assess the effect of dietary fiber intervention on gut microbiota composition.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Limited number of studies reporting α-diversity and small proportion using same diversity indexes.

    “Firstly, there were only a limited number of studies reporting the primary outcome of α-diversity, and a small proportion presenting data via the same diversity indexes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Feces are a surrogate for gut microbiota, and fecal composition differs from mucosal microbiota.

    “Furthermore, included studies sampled feces as a surrogate for gut microbiota profile, and although feces are a common sampling route, the microbial composition of feces differs from the mucosal microbiota (10,11), which is in closer contact with the host and may be more important when considering the relation between microbiota and disease pathophysiology or outcomes.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [10] Fraher, 2012, Techniques used to characterize the gut microbiota: a guide for the clinician, Nat Rev Gastroenterol Hepatol source

      Not checked in the free run.

    • cites [11] Zoetendal, 2002, Mucosa-associated bacteria in the human gastrointestinal tract are uniformly distributed along the colon and differ from the community recovered from feces, Appl Environ Microbiol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Limited number of taxa assessed may not convey overall effect.

    “Finally, the limited number of taxa assessed in the review may not convey the overall effect elicited by dietary fiber intervention on gut microbiota composition and metabolic outputs, although the selection of taxa was guided by the available literature.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Major strengths include robust design, comprehensive search, and use of 2 independent reviewers.

    “Major strengths of this study include its robust design, comprehensive search strategies, and the use of 2 independent reviewers.”
    Quote in the paperNot a substantial claim
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  • The paper relies on this without support.

    Dietary fiber is not digested by the host in the small intestine and reaches the colon where it is available to gut microbes.

    “It is a key candidate in facilitating changes in the gut microbiota, as it escapes digestion by the host in the small intestine to pass into the colon where it is available to the microbial community.”
1 of 1

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Many response-associated bacteria in the cohort have known roles in starch degradation and fiber fermentation.

    “Given that many of the response-associated bacteria identified in our cohort have known roles in starch degradation and fiber fermentation (25–29)”

    From Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response (2021) · cites this paper as [28]

  • Fiber supplementation enriched Bifidobacterium and Lactobacillus spp., with no effect on other common short-chain fatty acid producers except increases in Roseburia spp. and Faecalibacterium prausnitzii in parallel rather than crossover trials.

    “Fiber supplementation was found to enrich Bifidobacterium and Lactobacillus spp., whereas no effect was found on the other common SCFA producers except for increases in Roseburia spp. and F prausnitzii in parallel (rather than crossover) trials.”

    From Influence of the Gut Microbiome, Diet, and Environment on Risk of Colorectal Cancer (2020) · cites this paper as [128]

  • Fiber supplementation increased the concentration of butyrate in fecal samples.

    “Fiber supplementation increased the concentration of butyrate in fecal samples.128”

    From Influence of the Gut Microbiome, Diet, and Environment on Risk of Colorectal Cancer (2020) · cites this paper as [128]

  • A 2018 systematic review and meta-analysis of 64 studies found that dietary fibre interventions, particularly fructans and galactooligosaccharides (GOS), increase faecal abundance of Bifidobacterium and Lactobacillus species but did not affect alpha-diversity.

    “A 2018 systematic review and meta-analysis observed the effect of fibre on the gut microbiota from 64 studies. Dietary fibre interventions, particularly fructans and galactooligosaccharides (GOS), were found to increase faecal abundance of Bifidobacterium and Lactobacillus species but did not affect alpha-diversity [37].”

    From Effect of Diet on the Gut Microbiota: Rethinking Intervention Duration (2019) · cites this paper as [37]

  • Prebiotic consumption has been associated with growth of Bifidobacterium, Lactobacillus and lactic acid bacteria; conversely, fibres not classified as prebiotics do not appear to affect the abundance of Bifidobacterium or Lactobacillus.

    “Prebiotic consumption has been associated with growth of Bifidobacterium, Lactobacillus and lactic acid bacteria. Conversely, fibres not classified as prebiotics, do not appear to affect the abundance of Bifidobacterium or Lactobacillus [37].”

    From Effect of Diet on the Gut Microbiota: Rethinking Intervention Duration (2019) · cites this paper as [37]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • E. hallii study count conflicts with the cited trials

    Minor

    The paper says two studies measured E. hallii, but its account cites results from three distinct trials: reference 50 is a secondary report of trial 95, reference 62 is a separate trial, and reference 49 is a secondary report of trial 84.

1 of 1

Cites

Flagged first, then by citations

7 of the 132 references couldn’t be matched to a known paper.

Research works printed but not linked: 2

  1. Elmagarmid, 2014, Rayyan: a systematic reviews web app for exploring and filtering searches for eligible studies for Cochrane Reviews, Evidence-informed public health: opportunities and challenges. Abstracts of the 22nd Cochrane Colloquium
  2. Zeng, 2015, Effects of whole grain-bean mixed staple food on intestinal microecology and metabolic parameters of obese people, Chinese J Clin Nutr, 23, 27

Cited by

Sorted by citations

Related

Authors
So, D., Whelan, K., Rossi, M., Morrison, M., Holtmann, G., Kelly, J. T., Shanahan, E. R., Staudacher, H. M., & Campbell, K. L.
Affiliations
  • Bond University (AU)
  • King's College London (GB)
  • Translational Research Institute (AU)
  • The University of Queensland (AU)
Corresponding author
Campbell, Katrina L
ORCID
Venue
The American Journal of Clinical Nutrition
Publisher
Elsevier BV
Published
2018-06
Volume
107
Issue
6
Pages
965-983
ISSN
0002-9165 (ISSN-L)
DOI
10.1093/ajcn/nqy041
OpenAlex
W2790004059
Cited by
683
References
132
Citations by year
2026: 61 · 2025: 92 · 2024: 88 · 2023: 98 · 2022: 100 · 2021: 114 · 2020: 75 · 2019: 43 · 2018: 12
FWCI
5.98
Type
journal article
Language
en
Open access
Licence
Locations
  • American Journal of Clinical Nutrition (publishedVersion)
  • PubMed (publishedVersion)
  • Bond University Research Portal (Bond University) (submittedVersion, other-oa)
  • Own your potential (DEAKIN) (submittedVersion)
  • Figshare (submittedVersion, cc-by)
  • Research Portal (King's College London) (submittedVersion, other-oa)
  • Griffith Research Online (submittedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Gut microbiota and health
  • Health Sciences › Nursing › Nutrition and Dietetics › Microbial Metabolites in Food Biotechnology
  • Health Sciences › Nursing › Nutrition and Dietetics › Food composition and properties
Keywords
dietary fiber, gut microbiota composition, Bifidobacterium, Lactobacillus, short-chain fatty acids, butyrate, fructans, galactooligosaccharides, alpha diversity, healthy adults, dietary intervention, prebiotics, gut dysbiosis, chronic disease risk factors, fecal microbiota, bacterial abundance
MeSH terms
Gastrointestinal Microbiome, Adult, Bacteria, Dietary Fiber, Food Analysis, Humans

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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