Folic acid absorption in man: enhancing effect of glucose.

Folic acid absorption in the human jejunum was measured using tritiated pteroylglutamic acid in a triple lumen tube perfusion system. A comparison was made between absorption of folic acid in isotonic saline perfused in 11 subjects, and folic acid in isosmotic glucose and saline perfused in 10 subjects. Five subjects received both solutions. The addition of glucose resulted in a marked increase in folic acid absorption as well as in sodium and water absorption. There was a significantly positive correlation between folate absorption and water absorption for all subjects.