{"id":"99115bbe-7a71-51cf-8918-c1048dfa1a5c","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:c-high-oral-dose-oxaluria","predicate":"increases_urinary_oxalate_in_responder_subset","statement":"Nineteen of 48 participants, including 12 stone formers and seven non-stone formers, had more than 10% greater 24-hour oxalate excretion with 2 g/day vitamin C.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"a8b62b34-feab-5eb1-b005-758ab5308c9a","mechanism_event_label":"Some people excreted more oxalate after the high oral exposure.","subject":{"id":"2047867f-9872-53b2-a553-71c911d0695b","slug":"ascorbic-acid","display_name":"L-Ascorbic acid","entity_type_key":"small_molecule"},"object":{"id":"27cf19b4-41d7-5f81-8151-48667672310c","slug":"urinary-oxalate-excretion","display_name":"Urinary oxalate excretion","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"a8b62b34-feab-5eb1-b005-758ab5308c9a","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:c-high-oral-dose-oxaluria-event","event_type":"observed_intervention","label":"Some people excreted more oxalate after the high oral exposure.","description":"Nineteen of 48 participants, including 12 stone formers and seven non-stone formers, had more than 10% greater 24-hour oxalate excretion with 2 g/day vitamin C.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9c8d2b72-517d-5bb6-8589-cabd98267f65","slug":"oxalate","display_name":"Oxalate","entity_type_key":"ion"},"role":"measured_metabolite","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"2047867f-9872-53b2-a553-71c911d0695b","slug":"ascorbic-acid","display_name":"L-Ascorbic acid","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"27cf19b4-41d7-5f81-8151-48667672310c","slug":"urinary-oxalate-excretion","display_name":"Urinary oxalate excretion","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Oxalate is relevant to calcium oxalate stone chemistry.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Randomized controlled-diet crossover study: 29 calcium stone formers and 19 non-stone formers.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Ascorbic acid 1000 mg twice daily for six days versus no supplement for six days; 13C2 oxalate challenge after adaptation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Responders were defined by the observed rise; no incident-stone endpoint and no extrapolation to ordinary food intake.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin C research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Some people excreted more oxalate after the high oral exposure.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[c-massey2005] Ascorbate increases human oxaluria and kidney stone risk (2005). https://pubmed.ncbi.nlm.nih.gov/15987848/ DOI: 10.1093/jn/135.7.1673","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human blood or whole-person endpoints","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"abcfc1e1-8911-5188-b0ef-2b8d29b4be3f","evidence_kind":"source_excerpt","locator":"Lines 1645-1656","start_line":1645,"end_line":1656,"excerpt":"### c-high-oral-dose-oxaluria\nNineteen of 48 participants, including 12 stone formers and seven non-stone formers, had more than 10% greater 24-hour oxalate excretion with 2 g/day vitamin C.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Some people excreted more oxalate after the high oral exposure.\norganism: Homo sapiens\ntissue_or_cell_type: Human blood or whole-person endpoints\nexperimental_model: Randomized controlled-diet crossover study: 29 calcium stone formers and 19 non-stone formers.\nlimitations: Responders were defined by the observed rise; no incident-stone endpoint and no extrapolation to ordinary food intake.\nexposure: Ascorbic acid 1000 mg twice daily for six days versus no supplement for six days; 13C2 oxalate challenge after adaptation.\ncross_nutrient: Oxalate is relevant to calcium oxalate stone chemistry.\n[c-massey2005] Ascorbate increases human oxaluria and kidney stone risk (2005). https://pubmed.ncbi.nlm.nih.gov/15987848/ DOI: 10.1093/jn/135.7.1673","model_system":"Randomized controlled-diet crossover study: 29 calcium stone formers and 19 non-stone formers.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [c-massey2005] Ascorbate increases human oxaluria and kidney stone risk (2005). https://pubmed.ncbi.nlm.nih.gov/15987848/ DOI: 10.1093/jn/135.7.1673","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"fa811221-13bd-5c10-adc1-eaf097c7703c","stable_key":"import-cb568d28-484a-5c2e-9fcc-2d780358e514","title":"Vitamin C: mechanisms, deficiency 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":"b7fd83f956abb81855f2ea23199ba14e465cd91f4a2ac560277ec21ddafd7bfc","revision_id":"6cde9bbb-d712-5746-82a6-85b144253efa","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}