ReviewAdvances in nutrition (Bethesda, Md.)2020
Tryptophan Metabolism: A Link Between the Gut Microbiota and Brain.
Review in Advances in nutrition (Bethesda, Md.), 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 544 papers, 2 of them syntheses that pooled it.
What it found
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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.
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.
Who cites it
544 citing papers in PubMed, 2 syntheses or guidelines pooled it, 880 citations in OpenAlex.
- Early-Life Microbiome and Neurodevelopmental Disorders: A Systematic Review and Meta-Analysis.Current neuropharmacology · 2026Pooled it
- The Association Between Nut Consumption and Risk of Depressive Symptoms: A Meta-Analysis of Observational Studies.Nutrients · 2025Pooled it
- Polyphenol-Rich Foods as a Healthy and Sustainable Strategy: Mental Health and Metabolomic Profiling.Molecular nutrition & food research · 2026Trial
- Hewei Jiangni recipe improved the quality of life in patients with cold-heat mixed nonerosive reflux disease: a randomized, double-blinded study.Journal of traditional Chinese medicine = Chung i tsa chih ying wen pan · 2025Trial
- Article
- Microbiome-driven alterations in tryptophan metabolism contribute to behavioral comorbidities in the Muc2 knockout mouse model of chronic colitis.Gut microbes · 2026Article
- Gut bacteria and their metabolites may influence our decisions, intelligence, cognition, and consciousness.Gut microbes · 2026Review
- Integrated metagenomic and metabolomic analysis identifies severity-specific inflammatory and metabolic signatures in post-stroke depression.Gut microbes · 2026Article
- Formulations containing co-biotic compounds mediate microbiome function and composition without increased gas production in anApplied and environmental microbiology · 2026Article
- Early-life microbial contact with adult hens modulates cecal microbiota and mitigates host responses to lipopolysaccharide-induced stress in broilers.Journal of animal science and biotechnology · 2026Article
- Cellular and systemic modifiers of alpha-synuclein proteostasis.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2026Review
- Gut microbiome dysbiosis is associated with aldosterone overproduction in idiopathic hyperaldosteronism.iScience · 2026Article
- Unraveling the Mechanistic Insights ofNutrients · 2026Review
- Early-Life Antibiotic Cocktail Intervention Alters Cecal Microbiota Composition and Metabolic Profiles in Suckling Rats.Microorganisms · 2026Article
- The Tryptophan-Kynurenine Pathway as a Key Mediator of the Gut-Brain Axis in Depression and Alzheimer's Disease.International journal of molecular sciences · 2026Review
- Gut microbiota as a modulator of HDAC: insights into Alzheimer's disease treatment.Pharmacological reports : PR · 2026Review
- Study of the Formation of Neuromodulatory Compounds in Fermented Products Based on Triticale, Naked Oat, and Amaranth Grains.Foods (Basel, Switzerland) · 2026Article
- Metabolic shifts driven by host-microbial interactions.The FEBS journal · 2026Review
- Recent advances in methotrexate pharmacology and potential therapeutic uses in age-related cardiometabolic and neurodegenerative diseases.Pharmacological reviews · 2026Review
- Body mass index-associated gut microbial taxa and functional pathways in women with benign and malignant breast disease.Breast cancer research and treatment · 2026Article
484 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The gut-brain axis (GBA) is a bilateral communication network between the gastrointestinal (GI) tract and the central nervous system. The essential amino acid tryptophan contributes to the normal growth and health of both animals and humans and, importantly, exerts modulatory functions at multiple levels of the GBA. Tryptophan is the sole precursor of serotonin, which is a key monoamine neurotransmitter participating in the modulation of central neurotransmission and enteric physiological function. In addition, tryptophan can be metabolized into kynurenine, tryptamine, and indole, thereby modulating neuroendocrine and intestinal immune responses. The gut microbial influence on tryptophan metabolism emerges as an important driving force in modulating tryptophan metabolism. Here, we focus on the potential role of tryptophan metabolism in the modulation of brain function by the gut microbiota. We start by outlining existing knowledge on tryptophan metabolism, including serotonin synthesis and degradation pathways of the host, and summarize recent advances in demonstrating the influence of the gut microbiota on tryptophan metabolism. The latest evidence revealing those mechanisms by which the gut microbiota modulates tryptophan metabolism, with subsequent effects on brain function, is reviewed. Finally, the potential modulation of intestinal tryptophan metabolism as a therapeutic option for brain and GI functional disorders is also discussed.
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Registered trials
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.