Vitamin A for Copd
Verdict: Insufficient Evidence
Across 6 PubMed studies, the evidence for Vitamin A in Copd grades Tier D — counter-evidence. Research is still too limited to draw a firm conclusion.
D 🔴 D Counter-Evidence Insufficient Evidence
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.31
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
D · Insufficient Evidence
Confidence
79%
Broadly consistent
Evidence level
E2
Multiple high-quality MAs (≥2 independent, consistent)
▸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 = 0.308
- 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 > 1 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 (6)L2 · primary research & systematic reviews
Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease (CARET)
Finding: Daily beta-carotene 30 mg plus vitamin A (retinyl palmitate) 25,000 IU in smokers/asbestos-exposed adults INCREASED lung cancer (RR 1.28, 95% CI 1.04-1.57, P=0.02) and total mortality (RR 1.17, 95% CI 1.03-1.33), prompting early trial termination.
View on PubMed The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers (ATBC)
Finding: Beta-carotene 20 mg/day in 29,133 male smokers did NOT reduce lung cancer and instead raised its incidence by 18% (95% CI 3-36%) and total mortality by 8% (95% CI 1-16%), showing no benefit and a harm signal.
View on PubMed Improvement of Lung Function by Micronutrient Supplementation in Patients with COPD: A Systematic Review and Meta-Analysis
Finding: Across 43 RCTs the benefit on lung function was driven by vitamin D (FEV1% WMD 6.39, 95% CI 4.59-8.18, p<0.01) and compound nutrients; vitamin A was NOT among the micronutrients analysed, so this meta-analysis provides no direct evidence for vitamin A.
View on PubMed Dietary Factors and Risk of Chronic Obstructive Pulmonary Disease: a Systematic Review and Meta-Analysis
Finding: Pooling 36 observational studies, no significant association was found between COPD risk and intake of beta-carotene (the vitamin A precursor), vegetables, n-3 fatty acids, or vitamin E.
View on PubMed Associations of Serum Vitamin A and E Concentrations with Pulmonary Function Parameters and Chronic Obstructive Pulmonary Disease
Finding: In 2,005 adults aged >=40, higher serum vitamin A was associated with better FEV1 (p-trend<0.01) and lower COPD prevalence (highest vs lowest tertile OR 0.53, 95% CI 0.31-0.90), but this is a cross-sectional surrogate association, not proof that supplementation helps.
View on PubMed The Effectiveness of Supplementation with Key Vitamins, Minerals, Antioxidants and Specific Nutritional Supplements in COPD - A Review
Finding: This narrative review found no human RCTs of vitamin A supplementation in COPD in the prior five years and no clear statistical evidence that vitamin A supplements benefit the lung, favouring dietary intake over supplements.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
Vitamin A — GRAS — 21 CFR 184.1245, 184.1930 — Technical Effect: NUTRIENT SUPPLEMENT — SCOGS no. 118 source↗
L4b EU EFSA
Neutral
Vitamin A contributes to the normal function of the immune system; Vitamin A contributes to the maintenance of normal vision; Vitamin A contributes to the maintenance of normal skin; Vitamin A contributes to the maintenance of normal mucous membranes; Vitamin A has a role in the process of cell specialisation; Vitamin A contributes to normal iron metabolism. source↗
L4c UK NHS
Cautious
Do not take cod liver oil or any supplements containing vitamin A (retinol) when you're pregnant. Too much vitamin A could harm your baby. source↗
L4d TW TFDA / 衛福部
Neutral
維生素A 指示藥每日用量上限 10,000 IU（3,000 微克 RE）；換算：1 微克 RE = 1 微克 Retinol = 6 微克 β-Carotene；3 微克 RE = 10 IU。 source↗
L4e WHO
Supportive
In settings where vitamin A deficiency is a public health problem, vitamin A supplementation is recommended in infants and children 6-59 months of age as a public health intervention to reduce child morbidity and mortality (strong recommendation). source↗
L5a NIH Office of Dietary Supplements
Supportive
The most common clinical sign of vitamin A deficiency is xerophthalmia, which develops after plasma retinol has been low. The first sign is night blindness, or the inability to see in low light or darkness as a result of low rhodopsin levels in the retina. source↗
L5b Mayo Clinic
Against
Claims that vitamin A is effective for treatment of lung diseases have not been proven. source↗
L5d Harvard Health
Neutral
People who reported the highest intakes of vitamins A and E from both diet and supplements, and high intake of vitamin D just from supplements, had the fewest complaints of respiratory illness, such as colds, asthma, and chronic obstructive pulmonary disease. source↗