Vitamin B12 deficiency can occur for various reasons. One of them is an insufficient amount of saliva in the mouth. There are many medications that cause dry mouth. These are, for example, pioids, inhalers, decongestants, antidepressants, medicines for high blood pressure, benzodiazepines (Xanax).
Another possible risk factor for vitamin B12 deficiency is low stomach acid. This may be because the person is on anti-ulcer medications. Additionally, stomach acid production may decrease with age. Finally, the reason may be damage to the gastric mucosa, malfunction of the pancreas, taking metformin.
News cannot be equated to a medical prescription. Before making a decision, consult a specialist.