The body stores around 5 mg of folate for between 3 and 4 months. Folate is primarily stored in the liver.12
Folic acid is mainly absorbed in the jejunum by means of passive transport following the concentration gradient, and by means of active transport when folate binds to reduced-folate transporter 1 and 2 (RFT-1 and RFT-2) and folate binding protein (FBP). Folic acid is also absorbed in the ilium, solely by passive transport.12, 13 and 14 Folate, in either its monoglutamate or reduced monoglutamate form, is absorbed in a neutral pH environment (pH 7.4) facilitated by neutralization of the acid gastric environment by alkaline pancreatic juices.14 One of 2 enzymes, glutamate carboxypeptidase or polyglutamate hydrolase, are needed to hydrolyse folic acid polyglutamate (the form in which it is found in food) to its monoglutamate form. These enzymes are found on the luminal surface of the jejunum and ileum.13 and 14