{"id":"fd71d345-b264-50af-9293-00fa378a1ad3","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:va-retinoid-iron-solubility-assay","predicate":"increases_in_assay","statement":"Adding beta-carotene or vitamin A retained more iron in solution when the assay pH rose from acidic toward near-neutral.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"18ba1d00-43f1-5eb5-a127-8867272f5d73","mechanism_event_label":"A laboratory solubility result supported a proposed explanation for the meal findings.","subject":{"id":"73c24cd4-9ae8-5897-8359-fa4d9e8edecb","slug":"beta-carotene","display_name":"All-trans-beta-carotene","entity_type_key":"small_molecule"},"object":{"id":"776c0700-f147-5bc5-889b-e557846413e2","slug":"iron-solubility","display_name":"Iron solubility","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"18ba1d00-43f1-5eb5-a127-8867272f5d73","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:va-retinoid-iron-solubility-assay-event","event_type":"biochemical_relationship","label":"A laboratory solubility result supported a proposed explanation for the meal findings.","description":"Adding beta-carotene or vitamin A retained more iron in solution when the assay pH rose from acidic toward near-neutral.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ce392c9e-6483-5914-b18b-d6a2520dbbf6","slug":"vitamin-a","display_name":"Vitamin A","entity_type_key":"chemical_species"},"role":"parallel_additive","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"tested_iron_context","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"73c24cd4-9ae8-5897-8359-fa4d9e8edecb","slug":"beta-carotene","display_name":"All-trans-beta-carotene","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"776c0700-f147-5bc5-889b-e557846413e2","slug":"iron-solubility","display_name":"Iron solubility","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Retinoid/iron chemistry; hypothesis boundary retained.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cell-free pH-shift experiment.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Solubility alone neither proves a defined retinoid-iron complex nor absorption in vivo.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin A research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-a","display_name":"Vitamin A","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A laboratory solubility result supported a proposed explanation for the meal findings.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell-free chemistry","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"999a69eb-51de-551a-9c29-765069ebad62","evidence_kind":"source_excerpt","locator":"Lines 1554-1564","start_line":1554,"end_line":1564,"excerpt":"### va-retinoid-iron-solubility-assay\nAdding beta-carotene or vitamin A retained more iron in solution when the assay pH rose from acidic toward near-neutral.\nCondition category: normal\nnutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A laboratory solubility result supported a proposed explanation for the meal findings.\norganism: Homo sapiens\ntissue_or_cell_type: Cell-free chemistry\nexperimental_model: Cell-free pH-shift experiment.\nlimitations: Solubility alone neither proves a defined retinoid-iron complex nor absorption in vivo.\ncross_nutrient: Retinoid/iron chemistry; hypothesis boundary retained.\n[va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646","model_system":"Cell-free pH-shift experiment.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"0c5474e2-be48-547b-b287-9c07a59c9ff1","stable_key":"import-dff9f743-3766-5f20-a71e-d6d2bd5bfb6f","title":"Vitamin A: forms, mechanisms, deficiency and excess (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":"b217224b262abbd77d6a0c8c9beefff9c022fae4d31e2a5273915d769b9a6546","revision_id":"61008909-871f-575c-b5e2-21542689ea3c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}