Folate for Autism Prevention
Verdict: Published with Warning
Across 5 PubMed studies, the evidence for Folate in Autism Prevention grades Tier A — moderate evidence. Effective, but with safety or population caveats.
A 🔵 A Moderate Evidence Published with Warning
Why this grade7-layer evidence engine
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Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.71
D
C
B
A
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← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
A · Published with Warning
Confidence
85%
Highly consistent evidence
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 = 0.715
- 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
The Effect of Maternal Folic Acid Supplementation on Neurodevelopmental Disorders in Offspring: An Umbrella Review of Systematic Reviews and Meta-Analyses
Finding: Across 23 systematic reviews/meta-analyses, maternal folic acid supplementation was associated with lower ASD risk (pooled OR 0.66, 95% CI 0.55-0.79), ADHD (OR 0.86, 0.78-0.95) and behavioral problems (OR 0.75, 0.63-0.91), but NO association with motor, cognitive/intellectual or language development, and ~50% of included reviews were graded very-low quality.
View on PubMed Prenatal Folic Acid Supplements and Offspring's Autism Spectrum Disorder: A Meta-analysis and Meta-regression
Finding: Folic acid supplementation in early pregnancy was associated with reduced offspring ASD risk (OR 0.57, 95% CI 0.41-0.78), and intake of at least 400 ug/day with OR 0.55 (95% CI 0.36-0.83).
View on PubMed Review and meta-analysis found that prenatal folic acid was associated with a 58% reduction in autism but had no effect on mental and motor development
Finding: Pooled across 16 studies (756,365 children), prenatal folic acid was associated with a 58% reduction in ASD risk, but showed no protective effect on mental or motor development (better mental-development scores were paradoxically seen with low folic acid exposure).
View on PubMed Association of maternal prenatal folic acid intake with subsequent risk of autism spectrum disorder in children: A systematic review and meta-analysis
Finding: Across 8 observational studies (840,776 children, 7,127 ASD cases) the pooled association was NOT statistically significant (OR 0.91, 95% CI 0.73-1.13; HR analysis 0.66, 95% CI 0.38-1.17), indicating no clear difference in ASD risk.
View on PubMed Association of the Maternal Folic Acid Supplementation with the Autism Spectrum Disorder: A Systematic Review
Finding: Narrative synthesis of 17 studies found protective associations in most (e.g. ~40% lower risk with preconception use per Schmidt 2013) but no meta-analysis was performed, and excessive intake was flagged as a potential risk, so conclusions remained inconsistent.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
Health claims relating folate to risk of neural tube defects may be made on the label or in labeling of foods, including dietary supplements, provided that the requirements in this section are met. source↗
L4b EU EFSA
Supportive
L4c UK NHS
Neutral
It's recommended that all women who could get pregnant should take a 400 microgram folic acid supplement daily before pregnancy and until they're 12 weeks pregnant. source↗
L4d TW TFDA / 衛福部
Supportive
孕期缺乏葉酸，會增加胎兒腦及脊髓先天性神經管缺陷的風險。育齡婦女及準備懷孕婦女可在準備階段每日攝取400微克，懷孕期間每日攝取600微克。 source↗
L4e WHO
Neutral
Current evidence suggests that folic acid supplementation in the periconceptional period, either alone or in combination with other vitamins and minerals, can prevent neural tube defects. source↗
L5a NIH Office of Dietary Supplements
Supportive
L5b Mayo Clinic
Supportive
Some research suggests that taking folic acid when pregnant may help lower the risk of autism spectrum disorder in the child. source↗
L5c Cleveland Clinic
Supportive
Early evidence suggests folic acid may also be associated with a lower risk of autism, severe language delays and emotional issues. source↗
L5d Harvard Health
Supportive
There is no sure way to prevent ASD, but steps like taking folic acid before and during pregnancy and avoiding certain prenatal exposures may lower the risk. source↗
L5e Specialty Society (condition-mapped)
Supportive
The findings are also in line with a large body of research, by other scientists, showing that women who take prenatal vitamins containing folate have a lower risk of having children affected by autism. source↗