Are folate and folic acid (B-vitamin) the same thing?

Folate vs. Folic Acid: Understanding the Difference

No, folate and folic acid are not the same thing, though they are related forms of vitamin B9 with similar biological functions. Folate is the generic term for naturally occurring forms found in foods, while folic acid is the synthetic form used in supplements and fortified foods 1.

Key Differences Between Folate and Folic Acid

Chemical Structure and Source

• Folate:

  • Generic term referring to a family of molecules that vary in oxidation state and chemical structure 1
  • Naturally occurs in foods as polyglutamates 1
  • Found in leafy green vegetables, pulses (legumes), eggs, nuts, and whole grain products 1

• Folic Acid:

  • Synthetic, oxidized form of vitamin B9 1
  • Manufactured synthetically for supplements and food fortification 1
  • Rarely found naturally in foods 1

Bioavailability and Metabolism

• Folic acid is almost twice as bioavailable as natural food folates 1
• Folic acid must be converted in the body into the active form (folate) 1, 2
• Folic acid requires enzymatic reduction to become metabolically active, while some natural folate forms are already in reduced states 3

Dietary Folate Equivalents (DFE)

Due to differences in bioavailability, nutritional recommendations use DFE:

• 1 μg DFE = 1 μg food folate
• 1 μg DFE = 0.6 μg folic acid from fortified food
• 1 μg DFE = 0.5 μg folic acid supplement taken on empty stomach 1

Biological Functions

Both forms ultimately serve the same essential biological functions:

• Required for DNA and RNA synthesis
• Metabolism of amino acids
• One-carbon transfer reactions
• Remethylation of homocysteine to methionine
• Critical for rapidly dividing cells, especially during fetal development 1, 4

Clinical Implications

Neural Tube Defect Prevention

• Folic acid supplementation (0.4 mg daily) is recommended for women of childbearing age to prevent neural tube defects 5, 4
• Higher doses (4 mg daily) are recommended for women with previous neural tube defect-affected pregnancies 5

Potential Concerns with Folic Acid

• High doses of folic acid can mask vitamin B12 deficiency by correcting hematological abnormalities while allowing neurological damage to progress 5, 3
• Some individuals with MTHFR gene polymorphisms may have difficulty converting folic acid to its active form 6, 7

Alternative Forms

• 5-methyltetrahydrofolate (5-MTHF) is the predominant form of folate in circulation
• 5-MTHF supplementation may be advantageous for those with reduced ability to metabolize folic acid 6, 7

Common Pitfalls in Clinical Practice

1. Failing to distinguish between forms: Assuming all forms of vitamin B9 have identical properties and metabolism
2. Overlooking B12 deficiency: Always evaluate for concurrent B12 deficiency when treating folate deficiency 5
3. Dosing confusion: Not accounting for different bioavailability when switching between forms
4. Excessive supplementation: Unmetabolized folic acid may accumulate with high-dose supplementation in some individuals 8

In summary, while folate and folic acid serve similar biological functions, they differ in their chemical structure, source, bioavailability, and metabolism. Understanding these differences is important for appropriate clinical recommendations and supplementation strategies.