Folate for Homocysteine
Verdict: Counter-Evidence
Across 4 PubMed studies, the evidence for Folate in Homocysteine grades Tier D — counter-evidence. High-quality evidence indicates it is not effective (or is harmful) for this use.
D 🔴 D Counter-Evidence Counter-Evidence
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
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← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
D · Counter-Evidence
Confidence
86%
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 = 0.712
- 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 — 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 (4)L2 · primary research & systematic reviews
Lowering blood homocysteine with folic acid-based supplements: meta-analysis of randomised trials (Homocysteine Lowering Trialists' Collaboration)
Finding: Folic acid alone reduced blood homocysteine by ~25% (95% CI 23-28%); adding vitamin B12 (~0.5 mg/day) produced a further ~7% reduction; vitamin B6 produced no significant additional reduction. In typical Western populations daily folic acid plus B12 lowers homocysteine roughly a quarter to a third (e.g. from ~12 to 8-9 micromol/L).
View on PubMed Effects of homocysteine-lowering with folic acid plus vitamin B12 vs placebo on mortality and major morbidity in myocardial infarction survivors: a randomized trial (SEARCH)
Finding: Allocation to folic acid plus B12 reduced blood homocysteine by a mean of 3.8 micromol/L (28%), but did NOT reduce major vascular events (25.5% vs 24.8%; RR 1.04, 95% CI 0.97-1.12) or any vascular outcome; no adverse effect on cancer incidence.
View on PubMed Homocysteine lowering with folic acid and B vitamins in vascular disease (HOPE-2)
Finding: B-vitamin therapy lowered homocysteine but did NOT reduce the primary composite outcome (18.8% vs 19.8%; RR 0.95, 95% CI 0.84-1.07). Stroke alone was lower with vitamins (4.0% vs 5.3%; RR 0.75, 95% CI 0.59-0.97); hospitalizations for unstable angina were higher.
View on PubMed Folic Acid Supplementation and the Risk of Cardiovascular Diseases: A Meta-Analysis of Randomized Controlled Trials
Finding: Folic acid supplementation produced a 10% lower risk of stroke (RR 0.90, 95% CI 0.84-0.96) and a 4% lower risk of overall CVD (RR 0.96, 95% CI 0.92-0.99), but NO significant effect on coronary heart disease (RR 1.04, 95% CI 0.99-1.09). Effects were stronger where baseline folate was low and where homocysteine reduction was larger.
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
Although taking folic acid reduces the level of homocysteine and provides protection against stroke, it doesn't appear to decrease deaths from heart attack or other cardiovascular causes. source↗
L5c Cleveland Clinic
Supportive
L5d Harvard Health
Supportive
L5e Specialty Society (condition-mapped)
Cautious