Nutritional deficiency is caused by a lack of the vitamin in the diet, whereas acquired deficiency occurs when the intestinal absorption of the vitamin is interfered with by diseases and conditions such as pernicious anemia (an autoimmune disorder affecting intrinsic factor protein produced by gastric parietal cells), chronic atrophic gastritis, Crohn's and celiac diseases, gastric bypass surgery, and medications such as metformin, gastric acid secretion blockers (i.e., proton-pump inhibitors and H2-receptor antagonists), and others (2, 3)
Research context: For evidence on mechanisms, human and preclinical research, limitations, and safety, read AOD-9604 Peptide: Benefits, Uses, Side Effects, Dosage, and Research
There is no research showing that taking well over the recommended daily or weekly amount of B12 can be unsafe or detrimental to your health, and an official upper tolerable intake level has yet to be established
Generic: Cyanocobalamin (Vitamin B12)
