04 Review at week 12 Decide whether the research question has been answered
Patients should be aware that heavy, chronic ethanol use may counteract the therapeutic effects of vitamin B12
AMPK and AKT protein kinases hierarchically phosphorylate the N-terminus of the FOXO1 transcription factor, modulating interactions with 14-3-3 proteins
For severe deficiency, the AAFP recommends loading doses typically daily or every other day for one to two weeks followed by monthly maintenance injections

Other groups who may benefit include: Patients following gastric surgery (gastrectomy, bariatric procedures) where intrinsic factor production or absorption sites are compromised Individuals with malabsorption disorders such as Crohn's disease, coeliac disease, or chronic pancreatitis Strict vegans and vegetarians with dietary insufficiency, though oral supplementation is usually tried first Elderly patients with atrophic gastritis or reduced gastric acid production Patients on long-term metformin or proton pump inhibitors, which can impair B12 absorption [6] [8] Individuals with nitrous oxide exposure (recreational or medical), which can cause functional B12 deficiency Diagnosis typically involves serum B12 measurement, with levels below approximately 148 pmol/L (though thresholds vary between laboratories) generally indicating deficiency