Oral cobalamin (vitamin B₁₂) treatment. An update

The objective of this review was to evaluate oral cobalamin (vitamin B ₁₂) therapy in adult and elderly patients, from the perspective of a hematologist. PubMed was systematically searched for English and French articles published from January 1990 to January 2007. Data from our working group, the 'Groupe d'étude des carences en vitamine B₁₂des Hôpitaux Universitaires de Strasbourg', have also been included. Several prospective studies in well-determined population (n = 4), prospective randomized studies (n = 3) and a systematic review by the Cochrane group (n = 1) provide evidence that oral cobalamin therapy may adequately treat cobalamin deficiency, particularly hematological abnormalities or manifestations. These studies suggest that at least 1000 μg/day of oral cyanocobalmin are needed for pernicious anemia and a mean daily dose of 250 μg for food-cobalamin malabsorption. This present review confirms the previously reported efficacy of oral cobalamin treatment in adult and elderly patients.