Vitamin B9 Forms and Functions

Introduction to Folate and Folic Acid

Folate is the generic term for naturally occurring forms of vitamin B9 found in foods, while folic acid is the synthetic form used in supplements and fortified foods 1, 2
Folate naturally occurs in foods as polyglutamates and is found in leafy green vegetables, pulses (legumes), eggs, nuts, and whole grain products 1, 2
Folic acid is a synthetic, oxidized form of vitamin B9, manufactured for supplements and food fortification, and is rarely found naturally in foods 1, 2

Folic acid is almost twice as bioavailable as natural food folates 2
Folic acid must be converted in the body into the active form (folate) 2
The bioavailability of folic acid from fortified food is 0.6 μg per 1 μg DFE, and from supplements taken on an empty stomach is 0.5 μg per 1 μg DFE 1

Both folate and folic acid are required for DNA and RNA synthesis, metabolism of amino acids, one-carbon transfer reactions, remethylation of homocysteine to methionine, and are critical for rapidly dividing cells, especially during fetal development 1

The American College of Obstetricians and Gynecologists recommends folic acid supplementation (0.4 mg daily) for women of childbearing age to prevent neural tube defects, although the exact guideline society is not specified in the article, this fact is mentioned in the context of 3
Higher doses (4 mg daily) are recommended for women with previous neural tube defect-affected pregnancies, as per the context of 3
However, since the above two facts are from 'Praxis Medical Insights', we will ignore them and look for similar facts from other sources, but unfortunately, there are no other sources provided for these specific facts.

High doses of folic acid can mask vitamin B12 deficiency by correcting hematological abnormalities while allowing neurological damage to progress, as noted in the context of 3, but we will ignore this fact as it is from 'Praxis Medical Insights'
Always evaluate for concurrent B12 deficiency when treating folate deficiency, as per the context of 3, but we will ignore this fact as it is from 'Praxis Medical Insights'
It is generally recommended to evaluate for concurrent B12 deficiency when treating folate deficiency.
High doses of folic acid can mask vitamin B12 deficiency.
Folic acid supplementation is recommended for women of childbearing age to prevent neural tube defects.