Vitamin B12 Deficiency

Epidemiology varies based on etiologyThree commonest reasons being ○ autoimmune ○ malabsorption and dietary There is widespread global prevalence of Vitamin B12 deficiency resulting in considerable morbidity Can manifest at any age but prevalence generally increases with age In the UK and USA the prevalence is approximately 6 % in people < 60 and about 20 % in those older than 60.

Also referred to as cobalamin Two important roles○ DNA synthesis○ neurological functioning Absorbed in terminal ileum where it binds to intrinsic factor produced by gastric parietal cells Once absorbed B12 is used as a co-factor for enzymes that are involved in the synthesis of DNA , fatty acids and myelin Foods containing B12 derived only from animal products○ meat○ fish○ dairy B12 is stored in liver Body stores generally enough ( last 2-4 yrs ) --> deficiency from diminished intake may not manifest for few yrs If B12 is not absorbed for prolonged periods - hepatic stores would be eventually depleted leading to deficiency Recommended daily dose in small

Risk factors B12 deficiency Vegans / vegetarians H/O gastric or intestinal surgery H/O atrophic gastritis Pernicious anaemia Gastric malabsorption Intake of medications which can interfere with absorption of Vit...