Evidence mapPaperPMID 40537680Full record

Trial reportEuropean journal of clinical nutrition2025

Effect of dietary fiber on trimethylamine-N-oxide production after beef consumption and on gut microbiota: MEATMARK - a randomized cross-over study.

Melanie Haas, Beate Brandl, Klaus Neuhaus, Susanne Wudy, Karin Kleigrewe, Hans Hauner, Thomas Skurk

Abstract readRandomized Controlled Trial
In one paragraph

Trial report in European journal of clinical nutrition, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing 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

6 citing papers in PubMed.

  1. Review
  2. Review
  3. [Mechanisms of gutZhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences · 2026
    Review
  4. Review
  5. Review
  6. Review
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

7 authors.

Melanie HaasCore Facility Human Studies, ZIEL Institute for Food & Health, Technical University of Munich, Freising, Germany.ORCID http://orcid.org/0009-0002-5304-0981
Beate BrandlCore Facility Human Studies, ZIEL Institute for Food & Health, Technical University of Munich, Freising, Germany.ORCID http://orcid.org/0000-0002-9328-8108
Klaus NeuhausCore Facility Microbiome, ZIEL Institute for Food & Health, Technical University of Munich, Freising, Germany.ORCID http://orcid.org/0000-0002-6020-2814
Susanne WudyBavarian Center for Biomolecular Mass Spectrometry (BayBioMS), TUM School of Life Sciences, Technical University of Munich, Freising, Germany.ORCID http://orcid.org/0009-0001-6333-5233
Karin KleigreweBavarian Center for Biomolecular Mass Spectrometry (BayBioMS), TUM School of Life Sciences, Technical University of Munich, Freising, Germany.ORCID http://orcid.org/0000-0002-7718-0252
Hans HaunerSchool of Medicine and Health, Technical University of Munich, Munich, Germany.ORCID http://orcid.org/0000-0002-1682-5088
Thomas SkurkCore Facility Human Studies, ZIEL Institute for Food & Health, Technical University of Munich, Freising, Germany. skurk@tum.de.ORCID http://orcid.org/0000-0002-6875-1658

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

BACKGROUND/

objectivesThe gut-microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) has been linked to cardiovascular disease (CVD) risk, while dietary fiber is associated with reduced CVD risk and improved gut health. Considering these associations, we conducted a randomized, double-blind, pilot study to investigate the influence of fiber supplementation on intestinal TMAO formation after beef consumption. SUBJECTS/

methods13 volunteers underwent a two-week dietary fiber and placebo intervention. We assessed the effect of fiber supplementation on the gut microbiota and gene abundance of the enzyme cutC, a key enzyme for microbial TMA formation, a precursor for TMAO. We measured the TMAO response following beef consumption after the two-week intervention. We also examined the role of hepatic enzyme FMO3 on TMAO plasma levels.

resultsAlthough overall TMAO production did not change between the dietary fiber and placebo group (p-value = 0.26, 95% CI), subgroup analysis revealed that fiber supplementation attenuated TMAO formation following beef intake in participants with lower habitual meat consumption ( <3 times/week, p-value = 0.029, 95% CI). Furthermore, fiber intervention significantly downregulated microbial cutC gene abundance (p = 0.034, 95% CI), suggesting a mechanism by which fiber might reduce plasma TMAO levels. While dietary fiber intervention did not alter TMAO production across all participants, it showed a potential effect in individuals with lower habitual meat intake. The observed downregulation of cutC gene abundance suggests a mechanism for the beneficial impact of fiber on TMAO formation.

conclusionThese findings support the role of a high-fiber, low-meat diet as a promising strategy to mitigate TMAO-related CVD risk. Graphical abstract of the MEATMARK study. Created with BioRender.com. Haas, M. (2025) https://BioRender.com/x12v771 .

Indexed as

Dietary FiberGastrointestinal MicrobiomeMethylaminesRed MeatAdultAnimalsCattleCross-Over StudiesDietDietary SupplementsDouble-Blind MethodFemaleHumansMaleMiddle AgedOxygenasesDietary Fiberdimethylaniline monooxygenase (N-oxide forming)MethylaminesOxygenasestrimethyloxamine

Identifiers

PMID40537680
PMCPMC12537495

What Socratic holds

Textmetadata
LicenceCC BY
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 Socratic graph.