Zinc for Immune Function
Verdict: Published with Warning
Across 5 PubMed studies, the evidence for Zinc 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 0.48
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
B · Published with Warning
Confidence
79%
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 = 0.483
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 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
PubMed studies (5)L2 · primary research & systematic reviews
Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials
Finding: Across 28 RCTs, oral/intranasal zinc prevented 5 RTIs per 100 person-months vs placebo (95% CI 1-8; NNT=20; moderate-certainty); reduced day-3 symptom severity (MD -1.20 points, 95% CI -1.74 to -0.66; low-certainty); non-serious adverse events higher (RR 1.41, 95% CI 1.17-1.69; NNH=7; moderate-certainty)
View on PubMed Zinc for prevention and treatment of the common cold (Cochrane Review, Nault et al.)
Finding: Zinc may make little to no difference in risk of developing a cold; may reduce mean duration of cold symptoms by ~2 days vs placebo (low-certainty); higher rate of non-serious adverse events (nausea, mouth/nose irritation); evidence certainty largely low to very low
View on PubMed Zinc supplementation for acute and persistent watery diarrhoea in children: a systematic review and meta-analysis (J Glob Health)
Finding: Across 38 RCTs, zinc increased proportion of children recovered at last follow-up (RR 1.07) and reduced diarrhoea duration (MD -13.27 hours) vs placebo; vomiting more frequent with zinc (RR 1.46), but lower doses (5-20 mg) had better tolerability; effect strongest in malnourished children and in South Asian endemic-deficiency settings
View on PubMed Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial
Finding: Trial stopped early for futility; no significant difference between arms - usual care 6.7 days vs zinc 5.9 days vs vitamin C 5.5 days vs combination 5.5 days to 50% symptom reduction; high-dose zinc and/or ascorbic acid did not significantly decrease symptom duration in ambulatory COVID-19
View on PubMed The effect of zinc on the outcome of patients with COVID-19: A systematic review and meta-analysis of randomized controlled trials
Finding: Pooling 4 RCTs, zinc supplementation did not significantly reduce 28-day mortality, hospitalization, or length of stay vs control in COVID-19; trend toward reduced symptom duration in some subgroups but not statistically robust; evidence certainty low-to-moderate, limited number of trials
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4b EU EFSA
Supportive
contributes to normal function of the immune system source↗
L4c UK NHS
Cautious
You should be able to get all the zinc you need from your daily diet source↗
L4d TW TFDA / 衛福部
Supportive
鋅之每日最高攝食量不得超過30 mg source↗
L4e WHO
Supportive
zinc has been recommended by WHO and UNICEF as the only treatment to be coupled with oral rehydration salts for the treatment of all diarrhoea episodes source↗
L5a NIH Office of Dietary Supplements
Supportive
Zinc is an essential mineral involved in numerous aspects of cellular metabolism source↗
L5b Mayo Clinic
Cautious
zinc is needed for immune function source↗
L5c Cleveland Clinic
Cautious
Zinc plays a role in your immune system, helping it fight off invading bacteria and viruses source↗