{"id":"75776760-b898-5c6b-a984-7433cf8e9fbb","stable_key":"c18313f9-752e-5d54-867d-bbb36aa274ed:human-zinc-depletion","predicate":"decreases_in_recorded_experiment","statement":"Mild zinc deficiency was accompanied by reduced thymulin bioactivity despite normal plasma zinc in the small human study; repletion or laboratory zinc treatment restored activity.","claim_class":"observational","status":"source_recorded","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"88b89c55-2692-5410-9fa4-4919d135eea9","mechanism_event_label":"Mild zinc deficiency was accompanied by reduced thymulin bioactivity despite normal plasma zinc in the small human study; repletion or laboratory zinc treatment restored activity.","subject":{"id":"0429f0ff-c033-514b-9a4f-6f0f83268095","slug":"zinc","display_name":"Zinc","entity_type_key":"nutrient_element"},"object":{"id":"0bb3f35c-c83b-533e-a4c4-5f03eb2eeabe","slug":"human-thymulin-bioactivity","display_name":"Human circulating thymulin bioassay activity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"88b89c55-2692-5410-9fa4-4919d135eea9","stable_key":"c18313f9-752e-5d54-867d-bbb36aa274ed:human-zinc-depletion-event","event_type":"experimental_observation","label":"Mild zinc deficiency was accompanied by reduced thymulin bioactivity despite normal plasma zinc in the small human study; repletion or laboratory zinc treatment restored activity.","description":"The strongest small human study included two dietary-depletion volunteers, six mildly zinc-deficient adults with sickle-cell anemia and six without it. Plasma zinc was normal, while cellular zinc assessments suggested deficiency. Thymulin bioactivity fell and recovered with zinc repletion or laboratory zinc treatment; immune readouts also changed. This demonstrates a useful **human proof of concept**, not population-wide diagnostic accuracy or proof that thymulin mediated every benefit of zinc. [Prasad et al., 1988](https://www.jci.org/articles/view/113717)","status":"provisional","compartment":null,"participants":[{"entity":{"id":"0429f0ff-c033-514b-9a4f-6f0f83268095","slug":"zinc","display_name":"Zinc","entity_type_key":"nutrient_element"},"role":"tested factor","stoichiometry":null,"state_label":"Mild zinc deficiency or controlled dietary depletion","sequence_order":0,"notes":""},{"entity":{"id":"0bb3f35c-c83b-533e-a4c4-5f03eb2eeabe","slug":"human-thymulin-bioactivity","display_name":"Human circulating thymulin bioassay activity","entity_type_key":"cellular_process"},"role":"measured outcome","stoichiometry":null,"state_label":"decrease","sequence_order":1,"notes":""},{"entity":{"id":"23819462-9bdf-5856-beac-68b3dca9cf85","slug":"thymulin","display_name":"Thymulin","entity_type_key":"peptide"},"role":"bioassayed peptide","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","entity_type_key":"ion"},"role":"laboratory reactivation metal","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":"evidence_access","value_text":"Primary bibliographic record and abstract checked; full methods/figures not comprehensively reviewed.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_contrast","value_text":"{\"intervention\": \"Mild zinc deficiency or controlled dietary depletion\", \"comparator\": \"Zinc-replete or repleted comparison\", \"endpoint\": \"Mild zinc deficiency was accompanied by reduced thymulin bioactivity despite normal plasma zinc in the small human study; repletion or laboratory zinc treatment restored activity.\", \"effect_direction\": \"decrease\", \"combination\": \"single\", \"conditions\": []}","comparator":null,"unit":null,"notes":"Explicit extracted experimental comparison; source-derived draft.","entity":null},{"dimension":"experimental_model","value_text":"Two dietary-depletion volunteers; six mildly zinc-deficient sickle-cell adults and six without sickle-cell anemia. Not population diagnostic validation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"interpretation_status","value_text":"Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Interpret only within the recorded preparation, exposure and comparator. The complete source passage retains qualifications; unspecified doses/timing have not been extracted here. No clinical efficacy, nutrient deficiency or unique molecular mediation is inferred.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Mild zinc deficiency was accompanied by reduced thymulin bioactivity despite normal plasma zinc in the small human study; repletion or laboratory zinc treatment restored activity.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Serum thymulin in human zinc deficiency. | 1988 | DOI 10.1172/jci113717 | PMID 3262625 | https://www.jci.org/articles/view/113717","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Line 1 of the separately retained human zinc/thymulin excerpt; originally in the reviewed thymulin reference.","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":"5205a2c8-283f-5534-88cf-884a252efcbe","evidence_kind":"source_excerpt","locator":"Lines 1-1","start_line":1,"end_line":1,"excerpt":"The strongest small human study included two dietary-depletion volunteers, six mildly zinc-deficient adults with sickle-cell anemia and six without it. Plasma zinc was normal, while cellular zinc assessments suggested deficiency. Thymulin bioactivity fell and recovered with zinc repletion or laboratory zinc treatment; immune readouts also changed. This demonstrates a useful **human proof of concept**, not population-wide diagnostic accuracy or proof that thymulin mediated every benefit of zinc. [Prasad et al., 1988](https://www.jci.org/articles/view/113717)","model_system":"Two dietary-depletion volunteers; six mildly zinc-deficient sickle-cell adults and six without sickle-cell anemia. Not population diagnostic validation.","directness":"reported_statement","verification_status":"source_recorded","notes":"Exact excerpt of the retained AI-assisted reviewed reference; primary sources are cited in primary_references and access scope is retained. Not a verbatim quotation from a primary paper.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"5cbf4857-e072-59ee-a8ca-e77ac490a094","stable_key":"import-c18313f9-752e-5d54-867d-bbb36aa274ed","title":"Zinc availability and human thymulin bioactivity: study excerpt","document_type":"imported_text","citation_label":"Exact excerpt from the 3 October 2026 reviewed thymulin reference. Primary study: Prasad et al. 1988, https://www.jci.org/articles/view/113717. Small human proof of concept; not population diagnostic validation.","file_path":"","sha256":"d25a3183514149ec0360d64121573733f76626909754fd1563a11d5a76e57385","revision_id":"0b00d821-3188-577f-88a3-146231f05900","review_status":"source_recorded","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}