Abstract
Oral vitamin B12 (VB12) absorption was studied in 12 patients with selective VB12 malabsorption and in 6 age-matched healthy controls. Serum VB12 level was measured before and 3 h after oral administration of VB12 100 or 1000 micrograms. After administration of 1000 micrograms of VB12 an appreciable increase in the serum VB12 level was observed in patients as well as in controls. The mean of the increase in the serum VB12 level did not differ between patients and the controls (273 +/- 203 pg/mL, 180 +/- 71 pg/mL, respectively P > .05). Twelve patients previously treated by parenteral VB12 were switched to, and 2 newly diagnosed patients were started on, oral VB12 treatment of 1000 micrograms given every 2 weeks. Hematological parameters and serum VB12 levels remained stable after switching to oral therapy in the 12 patients. In the two newly diagnosed patients anemia was cured by orally administrated VB12. This study lends further support to the use of megadoses of VB12 as an alternative treatment for selective VB12 malabsorption.