{"id":"cd2c63ce-14fe-59c9-a038-de4039f2f6a7","stable_key":"e3f6ce02-0bd7-5103-acc1-68503ab6751b:carnitine-microbiome","predicate":"decreases_in_recorded_comparison","statement":"Antibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.","claim_class":"observational","status":"source_recorded","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"b312be7a-b6ce-552b-8abb-d95ad8ff820e","mechanism_event_label":"Antibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.","subject":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"object":{"id":"b35376f4-8e1c-530c-8dbe-bcd3ad8e404b","slug":"human-carnitine-tmao-challenge","display_name":"Human microbiome-dependent TMAO response to carnitine","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"b312be7a-b6ce-552b-8abb-d95ad8ff820e","stable_key":"e3f6ce02-0bd7-5103-acc1-68503ab6751b:carnitine-microbiome-event","event_type":"experimental_observation","label":"Antibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.","description":"### carnitine-microbiome\n\nAntibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.\nThe intervention was L-carnitine, not ALCAR. Mouse atherosclerosis and human cardiovascular associations in the paper are separate findings; neither proves an ALCAR cardiovascular outcome.\nModel and exposure: Human isotope challenge before/after antibiotic suppression and recovery; Koeth et al. 2013.\nLimitations: Limited to the recorded preparation, model, exposure and endpoint. Does not establish a human dietary deficiency, clinical benefit or unique molecular mediation.\nReference: Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. | 2013 | https://pubmed.ncbi.nlm.nih.gov/23563705/ | https://pmc.ncbi.nlm.nih.gov/articles/PMC3650111/ | https://doi.org/10.1038/nm.3145 | Access: Primary full text: relevant Results/Methods and figure descriptions reviewed; supplements only where explicitly stated.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"role":"tested factor","stoichiometry":null,"state_label":"Microbiota suppression during carnitine challenge","sequence_order":0,"notes":""},{"entity":{"id":"b35376f4-8e1c-530c-8dbe-bcd3ad8e404b","slug":"human-carnitine-tmao-challenge","display_name":"Human microbiome-dependent TMAO response to carnitine","entity_type_key":"cellular_process"},"role":"measured outcome","stoichiometry":null,"state_label":"decrease","sequence_order":1,"notes":""},{"entity":{"id":"ffdcd3fa-0e47-5c2b-96e2-00b7d1d5674e","slug":"trimethylamine","display_name":"Trimethylamine / TMA","entity_type_key":"small_molecule"},"role":"microbial intermediate","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"8b3c1617-bb80-5858-bde0-65e139efbc68","slug":"trimethylamine-n-oxide","display_name":"Trimethylamine N-oxide / TMAO","entity_type_key":"small_molecule"},"role":"measured product","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"2adc7121-010a-5cfb-b97c-5873c88a350a","slug":"fmo3","display_name":"Human flavin-containing monooxygenase 3","entity_type_key":"protein"},"role":"host oxidation pathway context","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text: relevant Results/Methods and figure descriptions reviewed; supplements only where explicitly stated.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_contrast","value_text":"{\"intervention\": \"Microbiota suppression during carnitine challenge\", \"comparator\": \"Same challenge before suppression\", \"endpoint\": \"Antibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.\", \"effect_direction\": \"decrease\", \"combination\": \"single\", \"conditions\": []}","comparator":null,"unit":null,"notes":"Explicit extracted experimental comparison; source-derived draft.","entity":null},{"dimension":"experimental_model","value_text":"Human isotope challenge before/after antibiotic suppression and recovery; Koeth et al. 2013.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"interpretation_status","value_text":"Source-derived curation with stated access limits; ungraded, not independent replication.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Limited to the recorded preparation, model, exposure and endpoint. Does not establish a human dietary deficiency, clinical benefit or unique molecular mediation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Acetyl-L-carnitine collection; exact intervention and molecular form govern interpretation.","comparator":null,"unit":null,"notes":"","entity":{"slug":"acetylcarnitine","display_name":"Acetyl-L-carnitine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Antibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. | https://pubmed.ncbi.nlm.nih.gov/23563705/ | https://pmc.ncbi.nlm.nih.gov/articles/PMC3650111/ | https://doi.org/10.1038/nm.3145","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Reviewed reference carnitine-microbiome; The intervention was L-carnitine, not ALCAR. Mouse atherosclerosis and human cardiovascular associations in the paper are separate findings; neither proves an ALCAR cardiovascular outcome.","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"739cb423-8645-5c36-8090-52bbbd1de341","evidence_kind":"source_excerpt","locator":"Lines 136-142","start_line":136,"end_line":142,"excerpt":"### carnitine-microbiome\n\nAntibiotic suppression of gut microbes markedly reduced TMAO production after a labeled carnitine challenge.\nThe intervention was L-carnitine, not ALCAR. Mouse atherosclerosis and human cardiovascular associations in the paper are separate findings; neither proves an ALCAR cardiovascular outcome.\nModel and exposure: Human isotope challenge before/after antibiotic suppression and recovery; Koeth et al. 2013.\nLimitations: Limited to the recorded preparation, model, exposure and endpoint. Does not establish a human dietary deficiency, clinical benefit or unique molecular mediation.\nReference: Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. | 2013 | https://pubmed.ncbi.nlm.nih.gov/23563705/ | https://pmc.ncbi.nlm.nih.gov/articles/PMC3650111/ | https://doi.org/10.1038/nm.3145 | Access: Primary full text: relevant Results/Methods and figure descriptions reviewed; supplements only where explicitly stated.","model_system":"Human isotope challenge before/after antibiotic suppression and recovery; Koeth et al. 2013.","directness":"reported_statement","verification_status":"source_recorded","notes":"Original paraphrase in the retained reviewed reference, not a verbatim primary-paper quotation. Access level is explicit.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"2588f904-245a-597a-8a12-65118013fb90","stable_key":"import-e3f6ce02-0bd7-5103-acc1-68503ab6751b","title":"Acetyl-L-carnitine: detailed mechanisms of action (reviewed 6 October 2026)","document_type":"imported_text","citation_label":"AI-assisted original review of primary studies and clearly identified official records. Exact primary access is stated; no independent replication is claimed.","file_path":"","sha256":"84cc82d6fbb0fd5d73c4ce779e9f88e7f0184ba2d29b18ad0f153815380f2975","revision_id":"dac7a950-dbe5-5c7a-9c70-2ea711d5c71a","review_status":"source_recorded","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}