State of the art review: oral and nasal vitamin B12 therapy in the elderly.

The objective of this narrative review was to provide an update on oral and nasal vitamin B12 (cobalamin) therapy in elderly patients. Relevant articles were identified by 'PubMed' and 'Scholar Google' search from January 2010 to July 2018 and through hand search of relevant reference articles. Additional studies were obtained from references of identified studies, the 'Cochrane Library' and the 'ISI Web of Knowledge'. Data retrieved from international meetings were also used, as was information retrieved from commercial sites on the web and data from 'CARE B12' research group. For oral vitamin B12 therapy, four prospective randomized controlled trials, eight prospective studies, one systematic and four reviews fulfilled our inclusion criteria. The studies included mainly or exclusively elderly patients (≥65-year-olds). In all of the studies, the mean age of the patients was at least 70 years except for two. The present review documents that oral vitamin B12 replacement at 1000 μg daily proved adequate to cure vitamin B12 deficiency, with a good safety profile. The efficacy was particularly marked when considering the noticeable improvement in serum vitamin B12 levels and haematological parameters, such as haemoglobin level, mean erythrocyte cell volume and reticulocyte count. The effect of oral cobalamin treatment in patients presenting with severe neurological manifestations has not yet been adequately documented. For nasal vitamin B12, only a few preliminary studies were available. We conclude that oral vitamin B12 is an effective alternative to intramuscular vitamin B12 injections in elderly patients. Oral vitamin B12 treatment avoids the discomfort, inconvenience and cost of monthly injections.