Vitamin B2 (Riboflavin) for Micronutrient Deficiency
For people who are actually deficient, vitamin B2 (riboflavin) reliably corrects riboflavin deficiency (ariboflavinosis) and reverses its classic signs. This is a textbook case of replacing a nutrient the body is missing, though the strongest trials measure blood-level markers more than long-term symptom outcomes.
Why this grade7-layer evidence engine
Riboflavin deficiency is, by definition, treated by riboflavin, so this is a straightforward repletion case rather than a speculative supplement claim. Regulators agree on the basics: the WHO classes riboflavin as an essential water-soluble vitamin (1.1-1.3 mg/day for adults), the FDA lists it as a nutrient supplement, and the EFSA has formally established cause-and-effect links to normal energy metabolism, skin, mucous membranes and vision. The Cleveland Clinic states plainly that riboflavin 'prevents and treats low riboflavin levels in your body.'
The clinical literature backs this up. A double-blind RCT (PMID 19952781, n=83) showed low-dose riboflavin (1.6 mg/day) normalized the deficiency marker EGRAC within 16 weeks, and a review of four such trials (PMID 27170501) found this dose consistently corrects biochemical deficiency. A systematic review (PMID 33118888) reported subclinical deficiency in 27-77% of older adults, all reversed by repletion, while a narrative review (PMID 29477226) confirms oral riboflavin (5-30 mg/day) clears the mucocutaneous signs of ariboflavinosis (cheilosis, glossitis) within weeks.
The grade is B (preliminary) rather than A because the modern RCT evidence rests largely on a biochemical endpoint (EGRAC) in small, single-center trials, and high-quality blinded data on clinical symptom resolution come mostly from reviews and older studies. Importantly, primary deficiency is rare in well-fed populations (mainly affecting heavy alcohol users, strict vegans, and pregnant or older adults with poor diets), so this is not a reason for the general public to supplement; a varied diet usually supplies enough, as the UK NHS notes.
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 = 0.658
- 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 — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status