Black Seed for Asthma
Early trials suggest black seed (Nigella sativa) may modestly improve asthma control and lung function when added to standard inhaled medication, but the evidence is small and uncertain, and it should never replace prescribed controller inhalers.
Why this grade7-layer evidence engine
Two meta-analyses (PMID 34658694, pooling 4 RCTs and 187 patients; PMID 31892440) consistently found that Nigella sativa significantly improved Asthma Control Test scores (SMD ~0.50) and FEV1 (SMD 1.84), though it did nothing for peak expiratory flow. Supporting RCTs include a double-blind, MRC-funded trial (PMID 28093815) showing a ~1.5-point ACT gain and lower blood eosinophils, and a trial (PMID 28151459) where 2 g/day improved FEV1 and lowered airway inflammation markers (FeNO, IgE).
The grade stays at preliminary (Tier B) because the evidence base is genuinely thin: only about four RCTs, heterogeneous and often poorly characterized preparations (seed powder vs oil) at varying doses, and a very wide FEV1 confidence interval (0.07-3.60) signaling imprecision. Most trials were low quality with undisclosed funding, and there are too few studies to rule out publication bias.
Regulators and clinics add caution rather than endorsement. The US FDA treats black seed only as a GRAS culinary spice (21 CFR 182.10), not as a proven supplement, while EFSA, NHS and WHO have not addressed it. Among major clinics only Cleveland Clinic comments, and it is merely cautiously supportive, stressing it is not a substitute for controller medication. Critically, every trial used black seed as an add-on to maintenance inhalers, and GINA/ATS guidelines do not endorse it.
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 = 0.573
- 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