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Stronger carrier findings are not a population-wide diabetes risk estimate or evidence about all chronic formulations.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Melatonin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"melatonin","display_name":"Melatonin","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"21 healthy European-ancestry participants: 10 risk carriers, 11 noncarriers","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Regulation by insulin itself changed as well as the response to glucose.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[melatonin-p42346809] Melatonin Impairs Glucose Tolerance, First-Phase Insulin Secretion, and Insulin Feedback Inhibition; Interaction With MTNR1B Diabetes Risk Variant. (2026). https://pubmed.ncbi.nlm.nih.gov/42346809/ DOI: 10.2337/dc26-0164","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Insulin-modified IV glucose test and beta-cell modeling","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"43fbe5a4-b989-53d0-930c-6aedb40f6383","evidence_kind":"source_excerpt","locator":"Lines 1215-1226","start_line":1215,"end_line":1226,"excerpt":"### melatonin-2026-insulin-feedback\nRisk carriers showed a slower insulin-induced decline in second-phase insulin secretion during melatonin exposure.\nCondition category: normal\nnutrient_topic: Melatonin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Regulation by insulin itself changed as well as the response to glucose.\norganism: 21 healthy European-ancestry participants: 10 risk carriers, 11 noncarriers\ntissue_or_cell_type: Insulin-modified IV glucose test and beta-cell modeling\nexperimental_model: Randomized double-blind placebo-controlled crossover physiology trial\nlimitations: Small genotype-stratified acute study published in 2026. Stronger carrier findings are not a population-wide diabetes risk estimate or evidence about all chronic formulations.\nexposure: 5 mg oral melatonin; five-day laboratory protocol\nevidence_span: {\"source_cache\": \"artifacts/melatonin-research/42346809.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"a8e4b84650338084b0a878a3b06138c9ef65502d7f9b119877434421b5131bc6\", \"start_char\": 0, \"end_char\": 1941, \"text_sha256\": \"a8e4b84650338084b0a878a3b06138c9ef65502d7f9b119877434421b5131bc6\"}\n[melatonin-p42346809] Melatonin Impairs Glucose Tolerance, First-Phase Insulin Secretion, and Insulin Feedback Inhibition; Interaction With MTNR1B Diabetes Risk Variant. 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