Cooked beef liver has the highest amount
[51] Diagnosis [edit] According to one review: "At present, no 'gold standard' test exists for the diagnosis of vitamin B 12 deficiency and as a consequence the diagnosis requires consideration of both the clinical state of the patient and the results of investigations." [52] The vitamin deficiency is typically suspected when a routine complete blood count shows anemia with an elevated mean corpuscular volume (MCV)
[18] Lactation studies demonstrate that maternal injections modestly elevate breast-milk B12 concentrations without adverse infant outcomes, supporting compatibility with breastfeeding while underscoring the need for maternal repletion to prevent neonatal deficiency
In older people, it can help alleviate the vitamin deficiency that can result from a lack of variety in diet, and can also help maintain energy levels and maintain memory function
National Center for Biotechnology Information (2023)
Older adults, for instance, often have reduced stomach acid production, which can make it challenging to absorb B12 from food
