ABSTRACT
Background: Current thinking, which is based mainly on rodent
studies, is that physiologic doses of folic acid (pterylmonoglutamic
acid), such as dietary vitamin folates, are biotransformed in the
intestinal mucosa and transferred to the portal vein as the natural
circulating plasma folate, 5-methyltetrahydrofolic acid (5-MTHF)
before entering the liver and the wider systemic blood supply.