Background: The standard treatment for cobalamin (vitamin B(12)) deficiency involves regular intramuscular cobalamin injection. It has been suggested that oral cobalamin therapy may be effective for treating patients who have food-cobalamin malabsorption.
Subjects and methods: We prospectively studied 10 patients with cobalamin deficiency and well-established food-cobalamin malabsorption who received 3000 microg or 5000 microg of oral crystalline cyanocobalamin once a week for at least 3 months. Complete blood counts and serum cobalamin, homocysteine, and folate levels were determined at baseline and after 3 months of treatment. Patients were reexamined after 6 months.
Results: After 3 months of treatment, all patients had increased hemoglobin levels (mean increase, 1.9 g/dL; 95% confidence interval: 0.9 to 3.9 g/dL;P <0.01 compared with baseline) and decreased erythrocyte cell volume (mean decrease, 7.8 fL; 95% confidence interval: 0.9 to 16.5 fL;P<0.001). However, 2 patients had only minor, if any, responses. Serum cobalamin levels were increased in all 8 patients in whom it was measured.
Conclusion: Our findings suggest that moderate doses of crystalline cyanocobalamin given orally may be an effective treatment for food-cobalamin malabsorption.