American Journal of Clinical Nutrition, Vol 2, 89-96, Copyright © 1954 by The American Society for Clinical Nutrition, Inc.

Serum and Urine CONCENTRATIONS of VITAMIN B₁₂ following Oral Administration of the Vitamin

¹ From the Division of Hematology, University of Louisville School of Medicine

In both normal individual and patients with pernicious anemia in relapse, serum concentrations of vitamin B₁₂ show no significant alteration following the oral administration of 1000 µg. of the vitamin. When the dosage is increased to 5000 µg., serum concentrations in both groups are increased. In pernicious anemia, there is a correlation between hematological response and the demonstration of the vitamin in the serum following oral therapy. Vitamin B₁₂ appears in the serum in combined form after adequate oral dosage. The absence of circulating free vitamin accounts for the failure to detect the increased urinary activity which is observed following parenteral therapy.