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Vitamin A for Vitamin A Deficiency

Verdict: Effective treatment for genuine vitamin A deficiency

In people who are actually deficient, vitamin A is a proven, evidence-backed treatment that reverses night blindness and dry eye and, in undernourished young children, lowers illness and death. It is not a remedy for the general, well-nourished population, and excess preformed vitamin A is harmful in pregnancy.

A 🔵 A Moderate Evidence Published

🔬Why this grade7-layer evidence engine

The grade rests on a strong, consistent evidence base aimed at the right population. A large Cochrane review of children aged 6-59 months (PMID 28282701; 47 trials, over 1.2 million children) found periodic high-dose supplementation cut all-cause death by roughly 12% (RR 0.88, 95% CI 0.83-0.93) and about halved measles incidence, and an independent meta-analysis (PMID 21868478, ~195,000 children) reported a similar mortality benefit. A pregnancy meta-analysis (PMID 21069707) and the WHO guideline (PMID 24575452) point the same direction.

It lands at moderate rather than top-tier because the picture is not uniform. The large DEVTA trial in north India (PMID 23472988, ~1 million children) found no clear mortality benefit (about RR 0.96). It was folded into the Cochrane pooled estimate, which still favors supplementation, and the muted result is attributed to a milder baseline deficiency and rising measles-vaccine coverage.

Authorities agree on both the use and its limits. WHO strongly recommends high-dose supplementation only where deficiency is a public-health problem; NIH Office of Dietary Supplements names night blindness and xerophthalmia as the hallmark signs; and Cleveland Clinic describes high-dose then tapered repletion as standard care. The benefit applies to genuinely deficient or high-risk people, not routine use in well-fed adults, and the UK NHS warns pregnant women to avoid retinol supplements because excess preformed vitamin A is teratogenic.

⚖️

Scoring transparency

All scores computed by a 7-layer evidence engine — fully auditable
Raw score 0.78
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
A · Published
Confidence
89%
Highly consistent evidence
Evidence level
E1
Cochrane high-quality SR/MA

How strongly each layer supports this effect

lower = less supportive
L1 ExamineGlobal benchmark
0.50
L3 MechanismPlausibility
0.75
L5 Clinical bodiesAuthoritative stance
0.78
L2 PubMedPrimary literature
0.85
L11 AI re-checkIndependent read
0.95
Against Mixed Supports
▸View the full decision path (audit trail)
  1. compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.783
  2. tier_from_score — 依分數區間映射至 tier letter
  3. apply_hec_rules — 高品質 SR/MA 顯示 positive (3 篇 > 0 negative)
  4. tier_strict_requirement_check — Tier 條件達標，未降階
  5. detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
  6. decide_status — 依 tier + dispute 結果決定 status

📄PubMed studies (5)L2 · primary research & systematic reviews

Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age
PMID: 28282701 2017 Cochrane SR n = 1,202,382
Finding: Vitamin A supplementation reduced all-cause mortality by 12% (RR 0.88, 95% CI 0.83 to 0.93; 19 trials, n=1,202,382; high-certainty evidence). VAS also reduced diarrhoea-specific mortality (RR 0.88, 95% CI 0.79 to 0.98), measles incidence (RR 0.50, 95% CI 0.37 to 0.67), diarrhoea incidence (RR 0.85, 95% CI 0.82 to 0.87), night blindness (RR 0.32) and xerophthalmia (RR 0.31). Authors conclude VAS is associated with a clinically meaningful reduction in mortality, morbidity and vision-related outcomes in children at risk of deficiency.
🟢 High quality Academic Effect size: [object Object]
View on PubMed
Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis
PMID: 21868478 2011 統合分析 n = 194,795
Finding: Pooled analysis of 17 trials (n≈194,000) showed VAS reduced all-cause mortality by 24% (RR 0.76, 95% CI 0.69 to 0.83). Diarrhoea-specific mortality fell 28% (RR 0.72, 95% CI 0.57 to 0.91); measles-specific mortality fell 20% (non-significant). Incidence of diarrhoea (RR 0.85) and measles (RR 0.50) was reduced. Authors estimate that universal VAS in deficient settings could prevent ~600,000 child deaths/year and recommend continued public-health implementation pending DEVTA results.
🟢 High quality Government Effect size: [object Object]
View on PubMed
Effect of six-monthly vitamin A supplementation on all-cause mortality of pre-school children in north India (DEVTA): cluster-randomised trial
PMID: 23472988 2013 隨機對照試驗 n = 1,000,000
Finding: Mortality rate ratio in VAS vs control clusters was 0.96 (95% CI 0.89 to 1.03), corresponding to a non-significant 4% mortality reduction — substantially smaller than the ~23% reduction expected from earlier meta-analyses. Authors conclude that in this north-Indian population where baseline vitamin A deficiency was moderate and measles vaccination coverage rising, 6-monthly VAS conferred no statistically significant mortality benefit. Results re-ignited debate but did not overturn Cochrane meta-analytic conclusion that VAS reduces mortality in deficient settings.
🟢 High quality Government Effect size: [object Object]
View on PubMed
Vitamin A supplementation during pregnancy for maternal and newborn outcomes
PMID: 21069707 2010 統合分析 n = 310,000
Finding: Prenatal vitamin A supplementation reduced maternal night blindness substantially (RR 0.79, 95% CI 0.64 to 0.98) and reduced maternal anaemia (RR 0.81). No significant effect on maternal mortality overall, though one large Nepali trial (Christian/West) had suggested benefit. Supports vitamin A supplementation in pregnant women with deficiency, particularly for night blindness and anaemia.
Government Effect size: [object Object]
View on PubMed
Guideline: Vitamin A Supplementation in Infants and Children 6–59 Months of Age
PMID: 24575452 2011 Other
Finding: Strong recommendation (high-quality evidence) for periodic high-dose VAS in children 6-59 months in vitamin A-deficient settings, based on consistent mortality reduction (~24%) from RCT meta-analyses. Guideline reaffirms VAS as a flagship global public-health intervention; subsequent 2017 Cochrane update (PMID 28282701) maintained the recommendation despite DEVTA's smaller effect.
🟢 High quality Government
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↗
L5c Cleveland Clinic
Supportive
Your healthcare provider will treat your vitamin A deficiency with high doses of a vitamin A supplement for several days. After several days, they'll have you take lower doses of vitamin A until your vision and skin issues start to resolve. source↗
L5d Harvard Health
Supportive
Vitamin A deficiency is rare in Western countries but may occur. ... Also at risk are adults and children who eat a very limited diet due to poverty or self-restriction. source↗
L5e Specialty Society (condition-mapped)
Supportive
In settings where vitamin A deficiency is a public health problem (prevalence of night blindness is 1% or higher in children 24–59 months of age or where the prevalence of vitamin A deficiency (serum retinol 0.70 µmol/l or lower) is 20% or higher in infants and children 6–59 months of age), high-dose vitamin A supplementation is recommended in infants and children 6–59 months of age (strong rec… source↗
✓PMID 100% verifiedevery citation checked via NCBI Entrez
🔬5 PubMed studiesindependently re-checked by multiple sub-agents
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