{"id":"84447ccc-6e80-5b01-892d-1c03da412174","stable_key":"0ad8610d-d575-5870-b7cd-763a9f750783:copper-copper-absorption-adaptation","predicate":"dietary_background_did_not_significantly_change","statement":"True fractional copper absorption after the standardized tracer dose was about 48% at both low and high background intakes, without a significant difference.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"1ae88ebb-c37c-5a9b-a8b7-d3bb30273e3f","mechanism_event_label":"In this experiment, excretion changed more clearly than the measured absorption fraction.","subject":{"id":"9f0afdde-1ec1-5c8a-bb5e-f3b2b75f67f6","slug":"copper","display_name":"Copper","entity_type_key":"nutrient_element"},"object":{"id":"8fdb06da-61cc-5647-b205-9ed0f3608938","slug":"intestinal-copper-absorption","display_name":"Intestinal copper absorption","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"1ae88ebb-c37c-5a9b-a8b7-d3bb30273e3f","stable_key":"0ad8610d-d575-5870-b7cd-763a9f750783:copper-copper-absorption-adaptation-event","event_type":"observed_intervention","label":"In this experiment, excretion changed more clearly than the measured absorption fraction.","description":"True fractional copper absorption after the standardized tracer dose was about 48% at both low and high background intakes, without a significant difference.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9f0afdde-1ec1-5c8a-bb5e-f3b2b75f67f6","slug":"copper","display_name":"Copper","entity_type_key":"nutrient_element"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"8fdb06da-61cc-5647-b205-9ed0f3608938","slug":"intestinal-copper-absorption","display_name":"Intestinal copper absorption","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/copper-research/12844388.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"5b6c40ba96ca6bba0b6d377caf643f3aebba366919c889e2e8f10be4b23a0def\", \"start_char\": 0, \"end_char\": 1336, \"text_sha256\": \"5b6c40ba96ca6bba0b6d377caf643f3aebba366919c889e2e8f10be4b23a0def\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Controlled copper intake and stable-isotope balance study","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Twelve men; 0.7, 1.6 or 6 mg/day intake periods with an oral 3 mg isotope challenge","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The isotope challenge was the same at each dietary background. Similar fractional absorption under this test does not mean copper absorption is invariant at every dose.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Copper research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"copper","display_name":"Copper","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human men","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"In this experiment, excretion changed more clearly than the measured absorption fraction.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[copper-p12844388] Adaptive responses in men fed low- and high-copper diets. (2003). https://pubmed.ncbi.nlm.nih.gov/12844388/ DOI: 10.1079/bjn2003887","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Whole-body copper handling","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"bab08d60-4fd2-5687-aa24-0b4c36e949d5","evidence_kind":"source_excerpt","locator":"Lines 1378-1389","start_line":1378,"end_line":1389,"excerpt":"### copper-copper-absorption-adaptation\nTrue fractional copper absorption after the standardized tracer dose was about 48% at both low and high background intakes, without a significant difference.\nCondition category: normal\nnutrient_topic: Copper research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: In this experiment, excretion changed more clearly than the measured absorption fraction.\norganism: Human men\ntissue_or_cell_type: Whole-body copper handling\nexperimental_model: Controlled copper intake and stable-isotope balance study\nlimitations: The isotope challenge was the same at each dietary background. Similar fractional absorption under this test does not mean copper absorption is invariant at every dose.\nexposure: Twelve men; 0.7, 1.6 or 6 mg/day intake periods with an oral 3 mg isotope challenge\nevidence_span: {\"source_cache\": \"artifacts/copper-research/12844388.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"5b6c40ba96ca6bba0b6d377caf643f3aebba366919c889e2e8f10be4b23a0def\", \"start_char\": 0, \"end_char\": 1336, \"text_sha256\": \"5b6c40ba96ca6bba0b6d377caf643f3aebba366919c889e2e8f10be4b23a0def\"}\n[copper-p12844388] Adaptive responses in men fed low- and high-copper diets. (2003). https://pubmed.ncbi.nlm.nih.gov/12844388/ DOI: 10.1079/bjn2003887","model_system":"Controlled copper intake and stable-isotope balance study","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [copper-p12844388] Adaptive responses in men fed low- and high-copper diets. (2003). https://pubmed.ncbi.nlm.nih.gov/12844388/ DOI: 10.1079/bjn2003887","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"9afba495-cbdc-51aa-998e-70a930dba3be","stable_key":"import-0ad8610d-d575-5870-b7cd-763a9f750783","title":"Copper: transport, cuproenzymes, deficiency, excess and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"84b0f62b2dae6835fa26902be87625c003c6c707492d3007e8f9d15420669008","revision_id":"d7e35b8b-3f77-56d9-90b5-5f542c63f321","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}