{"id":"84e7416f-56f1-5e26-887c-72a40a021687","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:nia-clin-methionine-output-preserved","predicate":"restriction_preserves_tested_output","statement":"After the nicotinamide challenge, urinary and plasma methylated-metabolite outputs were similar across ordinary, low-methionine and adequate-methionine periods despite negative nitrogen balance during restriction.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"84e20520-6e54-55f1-ae28-2f9e67bb5e43","mechanism_event_label":"Using methyl groups to dispose of nicotinamide did not automatically exhaust that capacity during this short low-methionine study.","subject":{"id":"9d39f561-740b-5f67-bba7-8a72ef612a99","slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"},"object":{"id":"f5034afe-cbf4-59d8-9da9-faaa729a301e","slug":"niacin-methylated-metabolite-output","display_name":"Methylated niacin metabolite output","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"84e20520-6e54-55f1-ae28-2f9e67bb5e43","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:nia-clin-methionine-output-preserved-event","event_type":"observed_intervention","label":"Using methyl groups to dispose of nicotinamide did not automatically exhaust that capacity during this short low-methionine study.","description":"After the nicotinamide challenge, urinary and plasma methylated-metabolite outputs were similar across ordinary, low-methionine and adequate-methionine periods despite negative nitrogen balance during restriction.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"08c27a3f-552e-5c92-8688-321a9b64a0d6","slug":"nicotinamide","display_name":"Nicotinamide","entity_type_key":"small_molecule"},"role":"challenge_substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b02a63e0-a972-53c5-8a3a-eea6b7578cd5","slug":"n1-methylnicotinamide","display_name":"N1-Methylnicotinamide","entity_type_key":"small_molecule"},"role":"methylated_product","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9d39f561-740b-5f67-bba7-8a72ef612a99","slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"f5034afe-cbf4-59d8-9da9-faaa729a301e","slug":"niacin-methylated-metabolite-output","display_name":"Methylated niacin metabolite output","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"Nicotinamide (challenge_substrate); N1-methylnicotinamide (methylated_product)","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/niacin-clinical-sources/swendseid1987.abstract.txt\", \"locator\": \"Indexed primary abstract\", \"file_sha256\": \"9a410f57b23d220c2f97bf589b82b31e6e6f6ca2a7b680c2720e1881a0a71b74\", \"start_char\": 0, \"end_char\": 1188, \"text_sha256\": \"9a410f57b23d220c2f97bf589b82b31e6e6f6ca2a7b680c2720e1881a0a71b74\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Sequential controlled diets; five men aged 25–32 years","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"10-day ordinary diet; 14 days at 285 mg methionine/day; 7 days at 725 mg/day; end-period nicotinamide challenge 102 micromol/kg","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Methylated metabolite outputs, not all methylation reactions or tissue SAM, were measured. Four participants achieving final-period nitrogen balance contributed the reported comparison. Short exposure, very small study; no inference of unlimited methyl capacity.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Niacin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"niacin","display_name":"Niacin (vitamin B3)","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Using methyl groups to dispose of nicotinamide did not automatically exhaust that capacity during this short low-methionine study.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[nia-clin-swendseid1987] Methylated niacin derivatives in plasma and urine after an oral dose of nicotinamide given to subjects fed a low-methionine diet. (1987). https://pubmed.ncbi.nlm.nih.gov/2957911/ DOI: 10.1093/ajcn/46.3.496","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Urine, plasma and nitrogen balance","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"f2e0e102-6fad-5488-8503-70d84381a2ec","evidence_kind":"source_excerpt","locator":"Lines 1177-1189","start_line":1177,"end_line":1189,"excerpt":"### nia-clin-methionine-output-preserved\nAfter the nicotinamide challenge, urinary and plasma methylated-metabolite outputs were similar across ordinary, low-methionine and adequate-methionine periods despite negative nitrogen balance during restriction.\nCondition category: nutrient_deficiency\nnutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Using methyl groups to dispose of nicotinamide did not automatically exhaust that capacity during this short low-methionine study.\norganism: Homo sapiens\ntissue_or_cell_type: Urine, plasma and nitrogen balance\nexperimental_model: Sequential controlled diets; five men aged 25–32 years\nlimitations: Methylated metabolite outputs, not all methylation reactions or tissue SAM, were measured. Four participants achieving final-period nitrogen balance contributed the reported comparison. Short exposure, very small study; no inference of unlimited methyl capacity.\nexposure: 10-day ordinary diet; 14 days at 285 mg methionine/day; 7 days at 725 mg/day; end-period nicotinamide challenge 102 micromol/kg\ncross_nutrient: Nicotinamide (challenge_substrate); N1-methylnicotinamide (methylated_product)\nevidence_span: {\"source_cache\": \"artifacts/niacin-clinical-sources/swendseid1987.abstract.txt\", \"locator\": \"Indexed primary abstract\", \"file_sha256\": \"9a410f57b23d220c2f97bf589b82b31e6e6f6ca2a7b680c2720e1881a0a71b74\", \"start_char\": 0, \"end_char\": 1188, \"text_sha256\": \"9a410f57b23d220c2f97bf589b82b31e6e6f6ca2a7b680c2720e1881a0a71b74\"}\n[nia-clin-swendseid1987] Methylated niacin derivatives in plasma and urine after an oral dose of nicotinamide given to subjects fed a low-methionine diet. (1987). https://pubmed.ncbi.nlm.nih.gov/2957911/ DOI: 10.1093/ajcn/46.3.496","model_system":"Sequential controlled diets; five men aged 25–32 years","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [nia-clin-swendseid1987] Methylated niacin derivatives in plasma and urine after an oral dose of nicotinamide given to subjects fed a low-methionine diet. (1987). https://pubmed.ncbi.nlm.nih.gov/2957911/ DOI: 10.1093/ajcn/46.3.496","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"a62b7b5b-786a-57e9-85e9-67c6912a5054","stable_key":"import-a9dd23c6-978a-5755-8bd8-f29bd1fe0cda","title":"Niacin: NAD metabolism, 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. 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