{"id":"01f701f9-36e0-5cc6-918d-7660c5ec3652","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abs-bauman-calcium-holotc","predicate":"reverses-tested-decline-in","statement":"In the comparative diabetes study, adding oral calcium after three months of metformin reversed the decline in serum holo-transcobalamin.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"9aca7e95-73b7-5787-ab07-94397bd147d4","mechanism_event_label":"Calcium increased the circulating B12-carrier marker after metformin.","subject":{"id":"8e2a5a1f-cd49-5f28-8611-325266fb78a6","slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"},"object":{"id":"8afe7740-2051-50ce-a713-e4f82fad6c3c","slug":"serum-holotranscobalamin-concentration","display_name":"Serum holotranscobalamin concentration","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"9aca7e95-73b7-5787-ab07-94397bd147d4","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abs-bauman-calcium-holotc-event","event_type":"observed_intervention","label":"Calcium increased the circulating B12-carrier marker after metformin.","description":"In the comparative diabetes study, adding oral calcium after three months of metformin reversed the decline in serum holo-transcobalamin.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b6d9b937-895d-5e0a-8cc5-0454a0b7d373","slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"},"role":"nutrient","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"519971b1-5aef-5ad7-8022-840144855cd0","slug":"metformin","display_name":"Metformin","entity_type_key":"drug"},"role":"drug-exposure","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"c0d594d4-1445-57e7-b689-d2fbbb2dc00a","slug":"human-holotranscobalamin","display_name":"Human transcobalamin-cobalamin complex","entity_type_key":"protein_complex"},"role":"measured-complex","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"8e2a5a1f-cd49-5f28-8611-325266fb78a6","slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"8afe7740-2051-50ce-a713-e4f82fad6c3c","slug":"serum-holotranscobalamin-concentration","display_name":"Serum holotranscobalamin concentration","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"true","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"21 adults with type 2 diabetes; 14 switched to metformin, then received calcium","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Oral calcium after three months of metformin; dose not specified in inspected abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Small sequential comparative intervention. Serum holo-TC is an indirect absorption readout and does not directly prove membrane calcium antagonism.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Calcium increased the circulating B12-carrier marker after metformin.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[bauman-2000-calcium] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Circulating holo-transcobalamin","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c2e3facf-a0a9-5847-b6be-5c749f04622b","evidence_kind":"source_excerpt","locator":"Lines 439-450","start_line":439,"end_line":450,"excerpt":"### b12-abs-bauman-calcium-holotc\nIn the comparative diabetes study, adding oral calcium after three months of metformin reversed the decline in serum holo-transcobalamin.\nCondition category: normal\nnutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Calcium increased the circulating B12-carrier marker after metformin.\norganism: Homo sapiens\ntissue_or_cell_type: Circulating holo-transcobalamin\nexperimental_model: 21 adults with type 2 diabetes; 14 switched to metformin, then received calcium\nlimitations: Small sequential comparative intervention. Serum holo-TC is an indirect absorption readout and does not directly prove membrane calcium antagonism.\nexposure: Oral calcium after three months of metformin; dose not specified in inspected abstract\ncross_nutrient: true\n[bauman-2000-calcium] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227","model_system":"21 adults with type 2 diabetes; 14 switched to metformin, then received calcium","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [bauman-2000-calcium] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. 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