Probiotics for Immune Function
Verdict: Published with Warning
Across 5 PubMed studies, the evidence for Probiotics in Immune Function grades Tier B — preliminary evidence. Effective, but with safety or population caveats.
B 🟡 B Preliminary Evidence Published with Warning
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.59
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
B · Published with Warning
Confidence
73%
Broadly consistent
Evidence level
E1
Cochrane high-quality SR/MA
▸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 = 0.587
- 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 — | B→D 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (5)L2 · primary research & systematic reviews
Probiotics for preventing acute upper respiratory tract infections (Cochrane Review)
Finding: Probiotics reduced participants with >=1 URTI (RR 0.76, 95% CI 0.67-0.87, low-certainty); >=3 URTIs RR 0.59 (0.38-0.91, moderate-certainty); duration MD -1.22 days (-2.12 to -0.33); antibiotic use RR 0.58 (0.42-0.81)
View on PubMed Probiotics for Preventing Upper Respiratory Tract Infections in Adults: A Systematic Review and Meta-Analysis of RCTs
Finding: URTI incidence RR 0.77 (95% CI 0.68-0.87, p<0.0001); episode rate RR 0.72 (0.60-0.86, p=0.0002); mean duration -2.66 days (-4.79 to -0.54, p=0.01); no excess AE
View on PubMed Probiotics and Fever Duration in Children With Upper Respiratory Tract Infections: A Randomized Clinical Trial
Finding: Probiotic group median 3 days vs placebo 5 days; adjusted RR 0.64 (95% CI 0.51-0.80); no meaningful safety differences
View on PubMed Probiotic Supplementation and Respiratory Infection and Immune Function in Athletes: Systematic Review and Meta-Analysis of RCTs
Finding: Symptom severity SMD -0.65 (95% CI -1.05 to -0.25, p=0.02); IL-6 -2.52 pg/mL (-4.39 to -0.66); TNF-alpha -2.31 pg/mL; limited effect on episode frequency or duration
View on PubMed Effect of fermented milk on upper respiratory tract infection in adults living in the haze area of Northern China: a randomized clinical trial
Finding: Common cold OR 0.38 (95% CI 0.17-0.81, p=0.013); influenza-like illness OR 0.32 (0.11-0.97, p=0.045); shorter duration (1.23 vs 4.78 days); IFN-gamma and sIgA elevated
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Cautious
FDA has not approved any probiotic product for use as a drug or biological product in infants of any age source↗
L4b EU EFSA
Against
a cause and effect relationship had not been established between the consumption of a combination of bacterial strains and reduction of gastro-intestinal discomfort source↗
L4c UK NHS
Cautious
There's some evidence that probiotics may be helpful in some cases, such as helping to ease some symptoms of irritable bowel syndrome (IBS). But there's little evidence to support many health claims made about them. source↗
L4d TW TFDA / 衛福部
Supportive
益生菌屬食品，並無治療疾病的效果 source↗
L4e WHO
Neutral
probiotic supplementation with the strains Bifidobacterium longum subsp. Infantis DSM33361 and Lactobacillus rhamnosus GG source↗
L5a NIH Office of Dietary Supplements
Supportive
Probiotics might reduce some symptoms of IBS. source↗
L5b Mayo Clinic
Supportive
Probiotics may be effective in preventing the common cold source↗
L5c Cleveland Clinic
Cautious
There's not enough evidence to draw solid conclusions, but there's enough for some healthcare providers to recommend trying them source↗
L5d Harvard Health
Cautious
We don't have any evidence yet as to how we might be able to use dietary supplements to correct problems. source↗
L5e Specialty Society (condition-mapped)
Cautious
administration of S. boulardii be avoided for persons who are immunocompromised, are critically ill, or have a central venous catheter source↗