{"id":"527bf1f8-8f8b-5a4b-a7e0-b0e74e5bf949","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:cal-carbonate-fasting-achlorhydria","predicate":"has_reported_effect_on","statement":"Fasting achlorhydric participants absorbed substantially less calcium from carbonate than from citrate.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"3f03eda2-4997-5b6b-bcb4-0be3dca2fc39","mechanism_event_label":"Low stomach acid can change how a calcium preparation is absorbed.","subject":{"id":"4ee1cbd0-1cec-58e1-9fee-bdb2c13db94d","slug":"calcium-carbonate","display_name":"Calcium carbonate","entity_type_key":"chemical_species"},"object":{"id":"53d44ad2-3648-5c31-8328-bcc1344961df","slug":"intestinal-calcium-absorption","display_name":"Intestinal calcium absorption","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"3f03eda2-4997-5b6b-bcb4-0be3dca2fc39","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:cal-carbonate-fasting-achlorhydria-event","event_type":"observed_intervention","label":"Low stomach acid can change how a calcium preparation is absorbed.","description":"Fasting achlorhydric participants absorbed substantially less calcium from carbonate than from citrate.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"4ee1cbd0-1cec-58e1-9fee-bdb2c13db94d","slug":"calcium-carbonate","display_name":"Calcium carbonate","entity_type_key":"chemical_species"},"role":"tested_input","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"53d44ad2-3648-5c31-8328-bcc1344961df","slug":"intestinal-calcium-absorption","display_name":"Intestinal calcium absorption","entity_type_key":"cellular_process"},"role":"measured_outcome","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"a04ab5be-287a-52ff-a503-ed77277772bb","slug":"calcium-citrate","display_name":"Calcium citrate","entity_type_key":"chemical_species"},"role":"comparator","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"role":"absorbed_species","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"11 achlorhydric patients and nine controls; 250 mg calcium isotope tests.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Fasting achlorhydric mean fractions: carbonate 0.042, citrate 0.452; normal subjects showed no significant formulation difference.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Not evidence that carbonate always fails or citrate always outperforms it.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Calcium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Low stomach acid can change how a calcium preparation is absorbed.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[cal-clin-recker1985] Calcium absorption and achlorhydria (1985). https://pubmed.ncbi.nlm.nih.gov/4000241/ DOI: 10.1056/NEJM198507113130202","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human clinical or absorption endpoint","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"7ebf5b3f-eadb-5559-b556-cd23d664ac0c","evidence_kind":"source_excerpt","locator":"Lines 1164-1174","start_line":1164,"end_line":1174,"excerpt":"### cal-carbonate-fasting-achlorhydria\nFasting achlorhydric participants absorbed substantially less calcium from carbonate than from citrate.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Low stomach acid can change how a calcium preparation is absorbed.\norganism: Homo sapiens\ntissue_or_cell_type: Human clinical or absorption endpoint\nexperimental_model: 11 achlorhydric patients and nine controls; 250 mg calcium isotope tests.\nlimitations: Not evidence that carbonate always fails or citrate always outperforms it.\nexposure: Fasting achlorhydric mean fractions: carbonate 0.042, citrate 0.452; normal subjects showed no significant formulation difference.\n[cal-clin-recker1985] Calcium absorption and achlorhydria (1985). https://pubmed.ncbi.nlm.nih.gov/4000241/ DOI: 10.1056/NEJM198507113130202","model_system":"11 achlorhydric patients and nine controls; 250 mg calcium isotope tests.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [cal-clin-recker1985] Calcium absorption and achlorhydria (1985). https://pubmed.ncbi.nlm.nih.gov/4000241/ DOI: 10.1056/NEJM198507113130202","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"3c083fa0-59c6-50e9-af42-678d0e3c1006","stable_key":"import-434e1e27-eb90-583a-956b-62472726ffba","title":"Calcium: mechanism-first literature curation (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":"965c934d6b147f2b62f8d45ce6d7a87681a600bfe5c46a585b4704889afd3fc1","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[{"id":"84879773-bb41-5c0e-a239-87046fd67309","title":"Calcium carbonate absorption depends on stomach acid and meals","kind":"context_difference","status":"qualified","why":"Fasting achlorhydria and breakfast dosing gave different results in the same study; neither supports an unconditional absorption ranking.","resolution":"Unresolved; needs review.","created_at":"2026-09-17 08:08:54","record_type":"qualification","display_label":"Source qualification","record_url":"/corrections/84879773-bb41-5c0e-a239-87046fd67309","sides":[{"conflict_id":"84879773-bb41-5c0e-a239-87046fd67309","ordinal":0,"label":"Low stomach acid can change how a calcium preparation is absorbed.","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","start_line":1164,"end_line":1174,"quote":"### cal-carbonate-fasting-achlorhydria\nFasting achlorhydric participants absorbed substantially less calcium from carbonate than from citrate.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Low stomach acid can change how a calcium preparation is absorbed.\norganism: Homo sapiens\ntissue_or_cell_type: Human clinical or absorption endpoint\nexperimental_model: 11 achlorhydric patients and nine controls; 250 mg calcium isotope tests.\nlimitations: Not evidence that carbonate always fails or citrate always outperforms it.\nexposure: Fasting achlorhydric mean fractions: carbonate 0.042, citrate 0.452; normal subjects showed no significant formulation difference.\n[cal-clin-recker1985] Calcium absorption and achlorhydria (1985). https://pubmed.ncbi.nlm.nih.gov/4000241/ DOI: 10.1056/NEJM198507113130202","source_key":"import-434e1e27-eb90-583a-956b-62472726ffba","source_title":"Calcium: mechanism-first literature curation (2026-09-17)","claim_ids":["527bf1f8-8f8b-5a4b-a7e0-b0e74e5bf949"]},{"conflict_id":"84879773-bb41-5c0e-a239-87046fd67309","ordinal":1,"label":"The meal changed the result seen during fasting.","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","start_line":1176,"end_line":1185,"quote":"### cal-carbonate-meal-achlorhydria\nCalcium carbonate given with a normal breakfast showed normal absorption in the achlorhydric participants.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The meal changed the result seen during fasting.\norganism: Homo sapiens\ntissue_or_cell_type: Human clinical or absorption endpoint\nexperimental_model: Meal comparison in the achlorhydria absorption study.\nlimitations: Small study; the meal experiment did not isolate a molecular rescue mechanism.\n[cal-clin-recker1985] Calcium absorption and achlorhydria (1985). https://pubmed.ncbi.nlm.nih.gov/4000241/ DOI: 10.1056/NEJM198507113130202","source_key":"import-434e1e27-eb90-583a-956b-62472726ffba","source_title":"Calcium: mechanism-first literature curation (2026-09-17)","claim_ids":["74af3455-cc2d-5172-ada3-da7219a579d2"]}]}],"research":null}