American Journal of Clinical Nutrition, Vol 22, 124-132, Copyright © 1969 by The American Society for Clinical Nutrition, Inc.

Role of the Jejunum in the Absorption of Folic Acid and Its Polyglutamates

¹ From the Division of Hepatic Metabolism and Nutrition, Department of Medicine, New Jersey College of Medicine and Dentistry, and East Orange Veterans Administration Hospital, East Orange, New Jersey

The absorption of two pteroylmonoglutamates, folic acid and folinic acid, and two pteroylpolyglutamates, pteroyldiglutamate and pteroyltriglutamate, were tested in a) normal subjects and patients with nutritional folate deficiency without history of intestinal disease and b) two patients with intestinal resection. All folates were well absorbed by normal subjects and patients with nutritional folate deficiency. The patient whose intestinal resection involved removal of all but 10 cm of the proximal small intestine did not absorb any of these folates. The other patient, whose intestinal resection involved principally the removal of the jejunum, could absorb the pteroylmonoglutamates but not the pteroylpolyglutamates. These results suggest that a normal jejunum is necessary for the deconjugation of the pteroylpolyglutamates, which are the principal folates in foodstuffs; on the other hand, pteroylmonoglutamates when administered can be absorbed through the small intestine even in the absence of a jejunum.