Evidence brief · Supplement
Folate (B9) for Neural-tube defect prevention
Evidence grade A — Periconceptional; population + RCT
- Overall grade
- Grade A
- Last revised
- 1
- graded outcome
- 0
- references listed
Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.
1 at grade A — 1 graded row
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Neural-tube defect preventionEvidence grade A
Periconceptional; population + RCT
Largehigh
The evidence in words
The verdict
For neural-tube defect prevention, Folate (B9) earns evidence grade A (large effect, high consistency) — there is real evidence here. Periconceptional; population + RCT
How it might work
Folate carries one-carbon units for the synthesis of purines, thymidine, and methionine, making it essential for rapidly dividing cells — including the neural tube that closes in the first month of gestation. It works in tight partnership with B12 in the methylation cycle.
How to use it
400 µg/day for anyone who could become pregnant, started before conception; higher doses are used under medical guidance for prior affected pregnancies. General supplementation of 400 µg is reasonable where diets are low in leafy greens and legumes.
Safety & cautions
Safe at typical doses. The main caution is masking B12 deficiency (see B12). Very high folic-acid intakes and unmetabolized folic acid are debated but not clearly harmful at supplemental doses.
Bottom line
If pregnancy is possible, 400 µg folic acid daily, starting before conception, is one of the best-evidenced supplements in existence. Outside that context it mainly corrects a dietary gap.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Periconceptional
- 400 µg folic acid daily, before and through early pregnancy.
- General
- 400 µg/day if leafy-green and legume intake is low.
Goes with
- Folate (B9)Read the full Folate (B9) monographEvidence grade A
Related reading
Entries that share this one's tags or conditions.
- Folate (B9) for Cardiovascular eventsEvidence grade D — Homocysteine lowering did not cut eventsEvidence grade D
- Folate (B9) for Homocysteine loweringEvidence grade A — Reliable biomarker effectEvidence grade A
- Folate (B9): dosage and how to take it400 µg folic acid daily, before and through early pregnancy.Evidence grade A
- Folate (B9): side effects, safety & interactionsSafe at typical doses. The main caution is masking B12 deficiency (see B12). Very high folic-acid intakes and unmetaboliEvidence grade A
Sources
This entry lists no references of its own — it is assembled from the entries it links to, whose sources are on their pages.
Last revised . A grade is this entry's reading of the evidence, not medical advice.