Common causes include: Pernicious anemia, an autoimmune disorder hindering Vitamin B12 absorption Gastrointestinal surgeries, like gastrectomy, impact Vitamin B12 uptake Long-term use of certain medications, such as metformin or proton pump inhibitors Diets lacking in Vitamin B12, often seen in vegans and vegetarians For those without a deficiency, Vitamin B12 injections are not typically recommended, as their body can naturally regulate and excrete excess amounts of the vitamin
Inadequate secretion of intrinsic factor, resulting from lesions that destroy the gastric mucosa (ingestion of corrosives, extensive neoplasia), and a number of conditions associated with a variable degree of gastric atrophy (such as multiple sclerosis, HIV infection, AIDS, certain endocrine disorders, iron deficiency, and subtotal gastrectomy)
The absence of large-scale human trials makes the true frequency of allergic responses across broader populations unknown
Springer Science and Business Media LLC
Research background matters because peptide handling, sequence stability, and route-specific formulation all affect interpretation
