Folate (B9)

• Folate function: Amino acid metabolism; Replication of DNA; Gene expression
• Dietary folate

  • Natural, Unstable, Essential vitamin
  • Activated to be methyl - folate
  • 50% bioavailable
• Folic acid

  • Synthetic B vitamin in supplements & fortified food
  • Stable
  • Nearly 100% bioavailable if taken in supplement/ empty stomach
• 60% of US population: Low folate status b/c gene variants that affect the activity of methyl - folate
• Folate and Congenital Abnormalities

  • Inadequate availability of folate 21-27 days after conception

  --> Interrupt normal cell differentiation --> Neutral Tube Defects

  1. Encephalocele: Protrusion of the brain thru the skull
  2. Anencephaly: no brain/ spinal cord
  3. Spina bifida: Spinal cord failing to close; Fluid collects in gap
• Folate status in US

  • Improved since folic acid fortification of refined grain products in 1998

  • 35% decline in NTD since folate fortification

  • HK no folic acid fortification program
• • Adult: 400 mcg/ day
  • Pregnancy: 600 mcg/ day [400 mcg from supplement + 200 mcg from veg & fruit]
  • Up to 4000 mcg/ day for high risk group (Women who have delivered a baby with NTD/ Family history)
  • UL: 1000 mcg/ day from supplement & fortified food (May mask neurological sign of B12 deficiency)
• Folate: water soluble; excess excreted out
• Fortified food > Food