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Vitamin B9

WATER-SOLUBLE

Tetrahydrofolate (THF), Folic acid

Folate (vitamin B9) exists naturally in foods as polyglutamate forms, while the synthetic form used in supplements is folic acid. In the body, folic acid is converted to tetrahydrofolate (THF), which serves as a carrier of one-carbon units in biosynthetic reactions essential for DNA, RNA, and amino acid synthesis. Because rapidly dividing cells have high requirements for DNA synthesis, folate is particularly critical during pregnancy to reduce the risk of neural tube defects.

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Key Functions

  • DNA and RNA synthesis
  • Cell division and growth
  • Amino acid metabolism
  • Red blood cell formation
  • Fetal neural tube development

Best Food Sources

Dark leafy greens (spinach, kale)Legumes (lentils, chickpeas)Asparagus and avocadoFortified grains and cerealsLiver and citrus fruits

Deficiency: Folate Deficiency

  • Megaloblastic anemia
  • Fatigue and weakness
  • Neural tube defects in fetus
  • Elevated homocysteine levels
  • Tongue swelling (glossitis)

High-Risk Groups

  • Women of childbearing age
  • Pregnant women
  • People with malabsorption
  • Chronic alcoholics

Sources

Reviewed for accuracy: Content is based on guidelines from the NIH Office of Dietary Supplements, Harvard T.H. Chan School of Public Health, and peer-reviewed medical literature.

Recommended Daily Amount

Adult Men

400 mcg

Adult Women

400 mcg; 600 mcg during pregnancy

Upper Limit (Tolerable)

1,000 mcg

Did You Know?

Folic acid fortification of grains has reduced neural tube defect incidence by 20-50% in countries that mandate it.

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