Beta-Glucan for Immune Function
Yeast and fungal beta-glucan shows only weak, inconsistent evidence for supporting immune function: a meta-analysis hints at fewer upper-respiratory infections, but the trials are heterogeneous, mostly industry-funded, and major regulators have rejected immune claims. It is not a proven way to boost immunity.
Why this grade7-layer evidence engine
The strongest signal is a single meta-analysis of 13 RCTs (PMID 33900466) finding yeast beta-glucan cut upper-respiratory-tract-infection (URTI) incidence (OR 0.345), episodes, and duration. But its authors flag high heterogeneity and small samples, and individual trials disagree: a 299-person RCT (PMID 30198828) reduced symptom severity more than infection rate, while a 100-person trial (PMID 28606567) found fewer confirmed infections (17 vs 28) yet only a non-significant trend for symptom-days (p=0.067).
Several positive results rest on surrogate immune-cell markers rather than fewer illnesses. A Reishi-derived beta-glucan RCT (PMID 36766186) raised NK-cell cytotoxicity by 83%, but blood-marker changes do not equal real-world protection. Industry funding is pervasive across these trials, so conflict of interest cannot be excluded, triggering the engine's funding warning.
Regulators reinforce the caution. The US FDA authorizes beta-glucan claims only for oat and barley fiber and heart disease, not for yeast immune effects, and EFSA has repeatedly rejected yeast beta-glucan immune and common-cold claims as causally unproven. With major clinics not endorsing it, a real-but-modest effect on a vague endpoint earns only a weak C grade.
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 = 0.449
- 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 + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status