[Vitamin B12 in the adult: of metabolism and deficiencies].

Purpose: Update on cobalamin deficiencies in adults.

Current Knowledge And Key Points: More precise definitions establish real cobalamin deficiency and determine epidemiological features. Current data on cobalamin metabolism suggest the concept of non-dissociation of vitamin B12 from its carrier proteins (NDB12), a generalization of the food-cobalamin malabsorption concept. The new features of cobalamin deficiency include neurological, gynecological and vascular manifestations. Current treatment modalities include nasal and oral administration of cobalamin.

Prospects And Projects: Validate the concept of NDB12 and the usefulness of oral cobalamin therapy, establish the relevance of the new clinical manifestations.