CAUSES OF B12 DEFICIENCY
The causes of vitamin B12 deficiency can vary and it can present in a wide range of patient groups. (2,12,13)
Limited vitamin B12 consumption from the diet as a result of malnutrition, reduced animal product intake or a strict plant-based diet. Those who exclude animal products may be at risk of deficiency if adequate amounts of alternative non-animal sources are not consumed.
Gastric Atrophy (Atrophic Gastritis)
Chronic inflammation of the stomach lining can disrupt the production of intrinsic factor, which is required to utilise vitamin B12. Atrophic gastritis can develop as part of the ageing process or Helicobacter Pylori infection. It can be a consequence of autoimmune gastritis, where partial cells or intrinsic factor, or both are destroyed, both of which are required for the digestion and absorption of vitamin B12. In this case, pernicious anaemia is diagnosed.
Intestinal infection or disease Inflammatory bowel disease, pancreatitis, tapeworm, giardiasis, intestinal bacterial overgrowth, short bowel syndrome.
Chronic inflammation of the gastrointestinal tract or disruption to the gut flora can disturb the digestion and absorption of vitamin B12.
Surgical intervention Gastric bypass, partial gastrectomy, ileal resections, surgical anastomosis
Surgical intervention can interfere with or result in the removal of the gastrointestinal areas that are essential for the digestion and absorption of vitamin B12.
There are a wide variety of medications that can impact on vitamin B12 levels. These include – Metformin, proton pump inhibitors, oral contraceptives, Colchicine (to treat gout), Cimetidine (to treat gastric ulcers), Phenobarbital, Pregabalin, Primidone and Topiramate (to treat epilepsy).