Efficacy of short-term oral cobalamin therapy for the treatment of cobalamin deficiencies related to food-cobalamin malabsorption: a study of 30 patients

Clin Lab Haematol. 2003 Jun;25(3):161-6. doi: 10.1046/j.1365-2257.2003.00515.x.


Background: It has been suggested that oral cobalamin (vitamin (B12)) therapy may be an effective therapy for treating cobalamin deficiencies related to food-cobalamin malabsorption. However, the duration of this treatment was not determined.

Patients and method: In an open-label, nonplacebo study, we studied 30 patients with established cobalamin deficiency related to food-cobalamin malabsorption, who received between 250 and 1000 microg of oral crystalline cyanocobalamin per day for at least 1 month.

Endpoints: Blood counts, serum cobalamin and homocysteine levels were determined at baseline and during the first month of treatment.

Results: During the first month of treatment, 87% of the patients normalized their serum cobalamin levels; 100% increased their serum cobalamin levels (mean increase, +167 pg/dl; P < 0.001 compared with baseline); 100% had evidence of medullary regeneration; 100% corrected their initial macrocytosis; and 54% corrected their anemia. All patients had increased hemoglobin levels (mean increase, +0.6 g/dl) and reticulocyte counts (mean increase, +35 x 10(6)/l) and decreased erythrocyte cell volume (mean decrease, 3 fl; all P < 0.05).

Conclusion: Our findings suggest that crystalline cyanocobalamin, 250-1000 microg/day, given orally for 1 month, may be an effective treatment for cobalamin deficiencies not related to pernicious anemia.

Publication types

  • Clinical Trial

MeSH terms

  • Aged
  • Aged, 80 and over
  • Blood Cell Count
  • Female
  • Hemoglobins / analysis
  • Homocysteine / blood
  • Humans
  • Malabsorption Syndromes / complications
  • Malabsorption Syndromes / drug therapy*
  • Male
  • Middle Aged
  • Treatment Outcome
  • Vitamin B 12 / administration & dosage*
  • Vitamin B 12 / blood
  • Vitamin B 12 / therapeutic use
  • Vitamin B 12 Deficiency / drug therapy*
  • Vitamin B 12 Deficiency / etiology


  • Hemoglobins
  • Homocysteine
  • Vitamin B 12