{"id":"21d1ca86-f70b-5aff-b5d1-8d60227e5d0f","stable_key":"911fb3c7-8cc3-5667-b677-5682fab67648:histidine-metabolic-human-trial","predicate":"improves_tested","statement":"In a randomized blinded trial of 100 obese women with metabolic syndrome, 4 g/day histidine for 12 weeks reduced HOMA-IR relative to placebo among 92 completers.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"0cc534c8-b9e4-5009-aa48-d3da640f156c","mechanism_event_label":"A human trial measured improved insulin-resistance-related outcomes in a selected group.","subject":{"id":"44374451-3436-5136-a8ae-5dcc6d8c353b","slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"},"object":{"id":"d40b8298-f1b0-54b0-a6d2-5564d2f96f80","slug":"human-histidine-mets-homa-ir","display_name":"HOMA-IR in the histidine metabolic-syndrome trial","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"0cc534c8-b9e4-5009-aa48-d3da640f156c","stable_key":"911fb3c7-8cc3-5667-b677-5682fab67648:histidine-metabolic-human-trial-event","event_type":"observed_relationship","label":"A human trial measured improved insulin-resistance-related outcomes in a selected group.","description":"In a randomized blinded trial of 100 obese women with metabolic syndrome, 4 g/day histidine for 12 weeks reduced HOMA-IR relative to placebo among 92 completers.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"44374451-3436-5136-a8ae-5dcc6d8c353b","slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d40b8298-f1b0-54b0-a6d2-5564d2f96f80","slug":"human-histidine-mets-homa-ir","display_name":"HOMA-IR in the histidine metabolic-syndrome trial","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Women aged 33-51; 50 assigned per arm, 45 histidine and 47 placebo completed.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"HOMA-IR is a surrogate; one population and duration. Separate adipocyte experiments do not prove the human mechanism; not a contradiction of isolated microbial-metabolite administration.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Histidine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A human trial measured improved insulin-resistance-related outcomes in a selected group.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Histidine supplementation improves insulin resistance through suppressed inflammation in obese women with the metabolic syndrome: a randomised controlled trial. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23361591/ · DOI 10.1007/s00125-013-2839-7","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"ae529f04-7ca5-5b7b-beed-19f36aaf4fef","evidence_kind":"source_excerpt","locator":"Lines 450-456","start_line":450,"end_line":456,"excerpt":"## histidine-metabolic-human-trial\nA human trial measured improved insulin-resistance-related outcomes in a selected group.\nIn a randomized blinded trial of 100 obese women with metabolic syndrome, 4 g/day histidine for 12 weeks reduced HOMA-IR relative to placebo among 92 completers.\nModel: Women aged 33-51; 50 assigned per arm, 45 histidine and 47 placebo completed.\nLimitations: HOMA-IR is a surrogate; one population and duration. Separate adipocyte experiments do not prove the human mechanism; not a contradiction of isolated microbial-metabolite administration.\nEvidence access: Primary abstract\nHistidine supplementation improves insulin resistance through suppressed inflammation in obese women with the metabolic syndrome: a randomised controlled trial. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23361591/ · DOI 10.1007/s00125-013-2839-7","model_system":"Women aged 33-51; 50 assigned per arm, 45 histidine and 47 placebo completed.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"ce59e6c9-1213-523b-9d0b-400b7a81cd1c","stable_key":"import-911fb3c7-8cc3-5667-b677-5682fab67648","title":"L-Histidine: supply, catabolism, histamine, receptors and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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