Skip to main content

Vitamin B9 (Folate) Guide: Essential Nutrient for DNA Health

Comprehensive guide to Vitamin B9 (Folate) including benefits for DNA synthesis, red blood cell formation, and fetal development. Food sources, deficiency symptoms, supplement options, and safety considerations.

DNA SynthesisRed Blood CellsFetal DevelopmentUpdated November 2025

What is Vitamin B9 (Folate)?

Understanding this essential water-soluble vitamin

Vitamin B9, also known as folate or folic acid, is a water-soluble B vitamin essential for DNA synthesis, repair, and methylation. It's crucial for rapid cell division and helps prevent neural tube defects in developing fetuses. Folate is the natural form found in foods, while folic acid is the synthetic form used in supplements and fortified foods.

Natural Folate

  • • Found in whole foods
  • • Multiple forms (folate polyglutamates)
  • • Water-soluble and easily absorbed
  • • Measured in micrograms (mcg)

Synthetic Folic Acid

  • • Used in supplements and fortified foods
  • • More stable and bioavailable
  • • Requires conversion to active form
  • • May mask vitamin B12 deficiency

DNA Synthesis

Essential for DNA replication and repair processes

Fetal Development

Critical for preventing neural tube defects during pregnancy

Key Functions of Vitamin B9

Why Vitamin B9 is essential for your health

DNA Synthesis & Repair

  • Essential for DNA replication during cell division
  • Supports DNA repair mechanisms
  • Critical for methylation processes
  • Important for rapid cell division in tissues

Red Blood Cell Formation

  • Prevents megaloblastic anemia
  • Supports healthy red blood cell maturation
  • Essential for hemoglobin synthesis

Homocysteine Metabolism

  • Converts homocysteine to methionine
  • Reduces cardiovascular disease risk
  • Supports neurotransmitter production
  • Important for brain health and mood

Fetal Development

  • Prevents neural tube defects (spina bifida)
  • Supports brain and spinal cord development
  • Essential during first trimester

Food Sources of Vitamin B9

Rich dietary sources of this essential nutrient

Leafy Green Vegetables

Spinach (1 cup cooked)263 mcg
Kale (1 cup cooked)177 mcg
Broccoli (1 cup cooked)168 mcg
Brussels sprouts (1 cup cooked)156 mcg

Other Rich Sources

Lentils (1 cup cooked)358 mcg
Chickpeas (1 cup cooked)282 mcg
Asparagus (1 cup cooked)268 mcg
Avocado (1 medium)122 mcg

Daily Value: The Daily Value (DV) for folate is 400 mcg for adults. Foods providing 20% or more of the DV are considered high sources.

Recommended Daily Intakes

RDAs for Vitamin B9 by age and life stage

By Age Group

Infants (0-12 months)65 mcg
Children 1-8 years150-200 mcg
Children 9-13 years300 mcg
Teens 14-18 years400 mcg

Adults & Special Groups

Adult women400 mcg
Adult men400 mcg
Pregnancy600 mcg
Lactation500 mcg

Note: Tolerable Upper Intake Level is 1,000 mcg/day for adults to avoid masking vitamin B12 deficiency symptoms.

Vitamin B9 Deficiency: Symptoms and Risks

Recognizing the signs of inadequate folate intake

Common Deficiency Symptoms

  • Megaloblastic anemia (large, immature red blood cells)
  • Fatigue and weakness
  • Mouth sores and tongue inflammation
  • Hair loss
  • Depression and irritability

Severe Deficiency & Pregnancy Risks

  • Neural tube defects (spina bifida, anencephaly)
  • Increased risk of preterm birth
  • Low birth weight
  • Developmental delays in infants

At Highest Risk

  • • Pregnant women and those planning pregnancy
  • • People with malabsorption disorders (celiac disease)
  • • Individuals with MTHFR gene mutations
  • • Those taking certain medications (methotrexate)
  • • People with alcohol dependence
  • • Elderly individuals

Vitamin B9 Supplement Options

When and how to consider supplementation

Supplement Forms

  • Tablets and capsules (folic acid or methylfolate)
  • Prenatal vitamins (usually contain 400-800 mcg)
  • Liquid supplements (for those with difficulty swallowing)
  • Sublingual forms (for better absorption)

Choosing the Right Supplement

  • Methylfolate for MTHFR gene mutations
  • USP verified for quality and purity
  • 400 mcg dosage for most adults
  • Third-party testing for contaminants

Important Considerations

  • • Avoid excessive intake (over 1,000 mcg daily) to prevent masking vitamin B12 deficiency
  • • Consult healthcare provider before starting supplementation
  • • Especially important for women planning pregnancy
  • • May interact with certain medications (anticonvulsants, methotrexate)
  • • Monitor for side effects like nausea or skin reactions

Interactions with Medications

Medications that may interact with vitamin B9

Potential Interactions

  • Methotrexate: Reduces folate levels, may require supplementation
  • Anticonvulsants: May interfere with folate metabolism
  • Sulfasalazine: Reduces folate absorption
  • Cholestyramine: May decrease folate absorption

Important Note

High doses of folic acid supplements may mask vitamin B12 deficiency symptoms, delaying diagnosis and treatment. Always inform your healthcare provider about vitamin B9 supplements.

Consult your doctor: Before starting folate supplementation, especially if you take medications or have medical conditions.

Vitamin B9 and Healthy Eating

Optimizing your diet for folate intake

Focus on a Folate-Rich Diet:

  • Dark leafy greens (spinach, kale, broccoli)
  • Legumes (beans, lentils, chickpeas)
  • Fresh fruits (citrus, avocado)
  • Vegetables (asparagus, Brussels sprouts)
  • Fortified cereals and grains
  • Fresh, minimally processed foods

Remember: Folate is sensitive to heat and light. Eat fresh foods and minimize cooking time to maximize nutrient retention. A varied, balanced diet provides the best foundation for health.

Scientific References

This guide is based on information from the National Institutes of Health Office of Dietary Supplements.

For more detailed scientific information, visit:https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/

Key studies and reviews cited: Institute of Medicine Dietary Reference Intakes for Folate, Neural Tube Defects Prevention Studies, MTHFR Gene Polymorphism Research, Cochrane Reviews on folate supplementation.

Optimize Your Vitamin B9 Intake

Understanding vitamin B9 is key to supporting DNA health, red blood cell formation, and fetal development. Make informed decisions about your nutrition.