Folate (B9)

Folate is a water-soluble B vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. “Folate,” formerly known as “folacin” and sometimes “vitamin B9,” is the generic term for naturally occurring food folates, and folates in dietary supplements and fortified foods, including folic acid. Food folates are in the tetrahydrofolate (THF) form and usually have additional glutamate residues, making them polyglutamates [1]. Folic acid is the fully oxidized monoglutamate form of the vitamin that is used in fortified foods and most dietary supplements. Some dietary supplements also contain folate in the monoglutamyl form, 5-methyl-THF (also known as L-5- MTHF, 5-MTHF, L-methylfolate, and methylfolate).. Folate functions as a coenzyme or cosubstrate in single-carbon transfers in the synthesis of nucleic acids (DNA and RNA) and metabolism of amino acids [1,3,4]. One of the most important folate-dependent reactions is the conversion of homocysteine to methionine in the synthesis of S-adenosyl-methionine, an important methyl donor. Another folate-dependent reaction, the methylation of deoxyuridylate to thymidylate in the formation of DNA, is required for proper cell division. An impairment of this reaction initiates a process that can lead to megaloblastic anemia, one of the hallmarks of folate deficiency [5].