MALABSORPTION SYNDROME: INTESTINAL ABSORPTION OF VITAMIN B_12

Abstract

Intestinal absorption of vitamin B12 was measured by the urinary excretion of radioactivity following the oral ingestion of a physiologic dose of Co58- or Co60- labelled vitamin B12 in patients with primary and secondary malabsorption syndromes. Absorption of vitamin B12 was impaired in 20 of 25 cases of primary malabsorption syndrome, in 3 cases of secondary malabsorption syndrome due to intestinal resection, and in 3 cases of blind-loop syndrome. Absorption of vitamin B12 in these patients was not related to or improved by intrinsic factor. As to intestinal absorption of vitamin B12, patients with malabsorption states can be divided into several groups: Primary malabsorption syndrome: Impaired absorption of vitamin B12 (four-fifths of our patients), normal absorption of vitamin B12 (one-fifth of our patients). Secondary malabsorption syndrome ("blind loop syndrome"): Impaired absorption of vitamin B12-not improved by antibiotics, impaired absorption of vitamin B12-improved by antibiotics. The significance of these findings in the pathogenesis of the characteristic hematologic abnormality of malabsorption syndrome is discussed.