Digestive Diseases and Sciences

, Volume 24, Issue 5, pp 397–402

Clinically significant vitamin B12 deficiency secondary to malabsorption of protein-bound vitamin B12

  • Charles E. King
  • John Leibach
  • Phillip P. Toskes
Original Articles

DOI: 10.1007/BF01297127

Cite this article as:
King, C.E., Leibach, J. & Toskes, P.P. Digest Dis Sci (1979) 24: 397. doi:10.1007/BF01297127

Abstract

Protein- (chicken serum) bound [57Co]cyanocobalamin absorption was evaluated in five hypochlorhydric patients who had developed B12 deficiency despite having normal absorption of unbound crystalline vitamin B12. All five patients had decreased urinary excretion of protein-bound B12 (0.06–0.34%) as compared to twelve normal controls (0.61–5.6%), P<.001. Improvement in protein-bound B12 absorption in four of the five patients occurred with the exogenous administration of hydrochloric acid, pepsin, gastric intrinsic factor, or a combination thereof. Vitamin B12 deficiency developing in the setting of hypochlorhydria may result from deficiency of acid-peptic digestion of B12 bound to protein and/or a relative deficiency of intrinsic factor. This digestive defect is not detected with tests which measure the absorption of unbound crystalline B12 but is detected by a simple test which employs B12 bound to chicken serum as the form of protein-bound B12.

Copyright information

© Digestive Disease Systems, Inc. 1979

Authors and Affiliations

  • Charles E. King
    • 1
  • John Leibach
    • 1
  • Phillip P. Toskes
    • 1
  1. 1.Veterans Administration Hospital and Department of MedicineUniversity of Florida College of MedicineGainesville
  2. 2.Gastroenterology SectionVeterans Administration HospitalGainesville