Vitamin B1 (Thiamine) for Micronutrient Deficiency
For documented thiamine (vitamin B1) deficiency, supplementation is established, often lifesaving standard care that reverses beriberi, Wernicke-Korsakoff syndrome, and refeeding-related deficiency. This strong grade applies only to correcting deficiency, not to general uses such as fatigue, diabetic neuropathy, or heart failure in people who are not deficient.
Why this grade7-layer evidence engine
Thiamine is the textbook treatment for thiamine-deficiency diseases, and the clinical literature is unanimous. A 2026 systematic review of beriberi (PMID 40753975) notes that wet (cardiac) beriberi can reverse dramatically within hours to days of intravenous thiamine, and a refeeding-syndrome review (PMID 28087222) confirms thiamine loading of roughly 100-300 mg/day prevents complications with consistent improvement and no harm. An older review of thiamine biology (PMID 29477220) reinforces deficiency correction as the definitive indication.
Notably, no placebo-controlled trial pits thiamine against nothing, because withholding it from at-risk patients is considered unethical given established efficacy. The two high-quality randomized trials are dose comparisons that assume thiamine works: a Cochrane review (PMID 23818100, one analyzable trial, n=107) found 200 mg/day beat 5 mg/day on a memory test but could not pin down optimal dose or route, and a 2022 double-blind RCT (PMID 35428992, n=520) found high doses no better than standard parenteral doses, with all arms improving.
Regulators and major clinics align. The WHO lists thiamine as an essential medicine for treating deficiency, EFSA recognizes its role in normal energy metabolism and nerve and heart function, and NIH, Mayo, Cleveland Clinic, and Harvard all describe supplementation as standard care for diagnosed deficiency. The UK NHS is cautious only about routine use in healthy adults who get enough from diet, which does not conflict with the deficiency-treatment claim.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.8
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — A 級條件達標
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status