# Folate (Vitamin B9)
URL: https://genohealth.app/nutrients/folate
Type: Nutrient
Evidence: Strong evidence
Last reviewed: 2025-06-30

## Intro
Folate (vitamin B9) is essential for one-carbon metabolism — the chemistry that builds DNA, methylates genes, and recycles homocysteine. The active form (5-methyltetrahydrofolate, 5-MTHF) is what the body actually uses, which is why MTHFR variants matter for some people.

## Summary
An essential B-vitamin that fuels methylation, DNA synthesis and neural development — and one of the most affected by MTHFR genetic variants.

## Key facts
- Daily needs: 400 mcg DFE adults · 600 mcg pregnancy
- Active form: 5-MTHF (L-methylfolate)
- Key gene: MTHFR (C677T, A1298C)

## Best food sources
- Leafy greens — spinach, romaine, arugula
- Legumes — lentils, chickpeas, black beans
- Liver (highest density)
- Asparagus, broccoli, Brussels sprouts
- Avocado, citrus, fortified grains

## Folate vs folic acid vs methylfolate
- Food folate — natural mix, converted to 5-MTHF before use
- Folic acid — synthetic, requires MTHFR to convert efficiently
- 5-MTHF (L-methylfolate) — the active form; bypasses MTHFR
- Folinic acid (calcium folinate) — gentler alternative for methyl-sensitive users

## When deficiency matters most
- Preconception and pregnancy — neural tube defect prevention
- MTHFR carriers with elevated homocysteine
- Heavy alcohol use, certain anticonvulsants, methotrexate
- Malabsorption (celiac, IBD)

## Related (knowledge graph)

### Genes
- MTHFR (/genes/mthfr): MTHFR encodes the enzyme that produces active folate (5-MTHF) from dietary and supplemental folate. [Strong evidence]

### Supplements
- L-Methylfolate (/supplements/methylfolate): L-methylfolate is the supplemental form of the active folate end-product. [Strong evidence]

## FAQ
**Q: Is folic acid bad for MTHFR carriers?**
A: Not at typical food-fortification doses. At higher supplemental doses, unmetabolized folic acid can accumulate; 5-MTHF or folinic acid avoid that issue.

**Q: How much folate do I need during pregnancy?**
A: Major guidelines recommend at least 600 mcg DFE/day from diet plus a prenatal containing folate or 5-MTHF, starting before conception.

## Citations
- Greenberg et al., Rev Obstet Gynecol 2011 (PMID 22132188): 5-MTHF is appropriate preconception folate for women with MTHFR variants.

Disclaimer: Informational only — not medical advice.