Folate (B9, folic acid / 5-MTHF)
EU-authorised health claim for reducing neural tube defect risk at 400 µg/day preconception. The clearest cause-and-effect vitamin claim in EU food law.
Why
Folate is the strongest example of a vitamin whose supplementation reduces a specific birth defect: the MRC Vitamin Study 1991 (Lancet) randomised 1,817 women at high risk of recurrence and found a 72% reduction in neural tube defects with periconceptional folic acid. EU Commission Regulation 1135/2014 authorised the disease-risk-reduction claim for 400 µg/day, taken from at least one month before conception through the first trimester. Outside pregnancy, folate also lowers plasma homocysteine, although the cardiovascular benefit of doing so has been modest in large trials.
How it works
One-carbon donor for DNA synthesis (thymidylate, purines) and methylation (via 5-methyltetrahydrofolate → methionine → SAM). 5-MTHF is the active form delivered to tissues; folic acid is reduced through DHFR before use.
Expected onset · Red-cell folate rises over 8–12 weeks; the NTD-prevention window opens after ≥4 weeks of preconception supplementation
How to take
Dosage
400 µg/day folic acid (EU-authorised dose for NTD risk reduction). 4–5 mg/day for women with a previous NTD-affected pregnancy (the MRC trial dose), only under medical supervision. 5-MTHF (methylfolate) is an alternative for those who prefer the active form, dosed equivalently.
Timing
Daily, ideally from ≥1 month preconception through the first trimester
On the label
Both folic acid and 5-MTHF (e.g. Quatrefolic, Metafolin) deliver the protective effect at 400 µg. Avoid combined products with ≥1 mg folic acid unless prescribed.
Ideal for
Anyone planning a pregnancy or able to become pregnant; people with known MTHFR variants or elevated homocysteine; long-term users of methotrexate, sulfasalazine, or anticonvulsants under clinician supervision.
Safety
Evidence
MRC Vitamin Study 1991 (Lancet, n=1,817 high-risk women): 4 mg/day folic acid preconception cut neural tube defect recurrence by 72% (RR 0.28, 95% CI 0.12–0.71). EU Commission Regulation 1135/2014 then authorised a disease-risk-reduction claim at 400 µg/day.
Where to get it
Shop Folate (B9, folic acid / 5-MTHF) on AmazonSponsored · As an Amazon Associate, Healicus earns from qualifying purchases.