Risk groups for cobalamin deficiency include individuals with:
- Inadequate intake, especially older women or men (>= 65 years).
- Long-term malnutrition and malnutrition, such as vegans, strict vegetarians.
- Decreased ability to digest protein / disruption of the release of the vitamin from food.
- “food-cobalamin malabsorption”, for example in hyperchlorhydria, pancreatic insufficiency, gastritis / Helicobacter pylori infection, under acid suppression therapy.
- An absence of intrinsic factor (in pernicious anemia or after gastrectomy).
- Inadequate absorption (after ileum resection, in Crohn’s disease).
- Taking medications, such as omeprazole and metformin (decrease absorption of vitamin B12).
- Increased consumption (in bacterial overgrowth or fish tapeworm infestation) (in HIV infection, multiple sclerosis).
- Malabsorption states (in HIV infection, multiple sclerosis).
- Congenital metabolic diseases (in transcobalamin deficiency, Imerslund-Gräsbeck syndrome).
Note on the state of supply (National Consumption Study II 2008).
8% of men and 26% of women do not reach the recommended daily intake.In women aged 14-24 years, the proportion of undersupplied is particularly high at 33% and then falls again with increasing age to 26% (65-80 years).