{"id":"5948b58d-e484-5df5-bc35-a041213361a6","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:nia-clin-restriction-nad","predicate":"low_availability_reduces","statement":"At both low niacin-equivalent intakes, erythrocyte NAD fell by about 70% in the seven-man feeding study and increased during adequate-intake repletion.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"a6aeb97b-9cfb-5611-88ab-b47b3457b7e8","mechanism_event_label":"With too little niacin and tryptophan, red blood cells lost much of their NAD supply; restoring intake raised it.","subject":{"id":"dfc664d3-d84d-55ca-afe2-1abbfafd83a7","slug":"niacin","display_name":"Niacin (vitamin B3)","entity_type_key":"nutrient_element"},"object":{"id":"92bba179-50c0-58e7-aaa6-dada08bfc336","slug":"erythrocyte-nad-content","display_name":"Erythrocyte NAD content","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"a6aeb97b-9cfb-5611-88ab-b47b3457b7e8","stable_key":"a9dd23c6-978a-5755-8bd8-f29bd1fe0cda:nia-clin-restriction-nad-event","event_type":"observed_intervention","label":"With too little niacin and tryptophan, red blood cells lost much of their NAD supply; restoring intake raised it.","description":"At both low niacin-equivalent intakes, erythrocyte NAD fell by about 70% in the seven-man feeding study and increased during adequate-intake repletion.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"769339cb-213b-559e-acc0-07ed00368b94","slug":"l-tryptophan","display_name":"L-Tryptophan","entity_type_key":"small_molecule"},"role":"alternative_precursor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"283ed24b-06a1-50aa-9281-df3bac6ce37e","slug":"nad-plus","display_name":"NAD+","entity_type_key":"small_molecule"},"role":"measured_coenzyme","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"dfc664d3-d84d-55ca-afe2-1abbfafd83a7","slug":"niacin","display_name":"Niacin (vitamin B3)","entity_type_key":"nutrient_element"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"92bba179-50c0-58e7-aaa6-dada08bfc336","slug":"erythrocyte-nad-content","display_name":"Erythrocyte NAD content","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":"L-Tryptophan (alternative_precursor); Nicotinamide adenine dinucleotide, oxidized (measured_coenzyme)","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/niacin-clinical-sources/fu1989.abstract.txt\", \"locator\": \"Indexed primary abstract\", \"file_sha256\": \"ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc\", \"start_char\": 0, \"end_char\": 1340, \"text_sha256\": \"ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Controlled metabolic-unit feeding; seven men, 80 days","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. 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Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials.\nexposure: 6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine\ncross_nutrient: L-Tryptophan (alternative_precursor); Nicotinamide adenine dinucleotide, oxidized (measured_coenzyme)\nevidence_span: {\"source_cache\": \"artifacts/niacin-clinical-sources/fu1989.abstract.txt\", \"locator\": \"Indexed primary abstract\", \"file_sha256\": \"ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc\", \"start_char\": 0, \"end_char\": 1340, \"text_sha256\": \"ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc\"}\n[nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. 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