Folate
Vitamin B9 — critical for DNA methylation, cell division, and homocysteine metabolism.
Optimal Range
> 10 ng/mL (optimal) · 3-20 ng/mL (lab range)
Risk-Stratified Targets
| Population / Context | Target |
|---|---|
| Optimal | > 10 ng/mL |
| Adequate | 5–10 ng/mL |
| LowLikely impaired methylation; check homocysteine | 3–5 ng/mL |
| DeficientRisk of megaloblastic anemia and elevated homocysteine | < 3 ng/mL |
Why It Matters
Folate is essential for proper DNA methylation — a key epigenetic process that regulates gene expression and aging. Deficiency elevates homocysteine and impairs cellular repair. MTHFR gene variants affect folate metabolism in ~40% of the population.
Understanding Folate
Folate (vitamin B9) is a critical cofactor in one-carbon metabolism — the biochemical pathway responsible for DNA synthesis, DNA repair, DNA methylation, and homocysteine recycling. These processes are fundamental to cellular replication and epigenetic regulation, making adequate folate status essential for healthy aging at the molecular level.
DNA methylation, in particular, has emerged as a central mechanism in aging research. Epigenetic clocks (like Horvath and GrimAge) measure methylation patterns to determine biological age. Proper methylation depends on a supply chain that includes folate, B12, B6, and the enzyme MTHFR. Variants in the MTHFR gene — present in approximately 40% of the population — reduce the enzyme's ability to convert dietary folate to its active form (5-MTHF). Individuals with MTHFR variants may have normal serum folate but impaired methylation capacity, often reflected in elevated homocysteine.
For individuals with known MTHFR variants or elevated homocysteine, supplementation with methylfolate (5-MTHF) rather than folic acid is generally recommended, as methylfolate bypasses the impaired enzymatic step. Food sources rich in natural folate include dark leafy greens, legumes, and liver. Folate needs increase during pregnancy (to prevent neural tube defects), with rapid cell turnover, and in conditions of chronic inflammation or heavy alcohol use.