This is known as macrocytic anemia
Note: long-term use of drugs that affect stomach acid production such as H2 blockers and proton pump inhibitors can worsen B12 deficiency
Heres how they fit into a few common concerns
Experts say, The unique chemical makeup of Vitamin B12 and iron explains their different roles in our bodies. Cobalamins complex structure allows it to participate in methylation reactions and DNA synthesis, whereas irons role in hemoglobin is critical for oxygen delivery to tissues. Dietary Sources of Each Nutrient Vitamin B12 is mainly found in animal products like meat, poultry, fish, seafood, eggs, and dairy

Cyanocobalamin is indicated for Vitamin B12 deficiencies due to malabsorption which may be associated with the following conditions: Addisonian (pernicious) anemia Gastrointestinal pathology, dysfunction, or surgery, including gluten enteropathy or sprue, small bowel bacterial overgrowth, total or partial gastrectomy Fish tapeworm infestation Malignancy of pancreas or bowel Folic acid deficiency It may be possible to treat the underlying disease by surgical correction of anatomic lesions leading to small bowel bacterial overgrowth, expulsion of fish tapeworm, discontinuation of drugs leading to vitamin malabsorption (see Drug/Laboratory Test Interactions), use of a gluten-free diet in nontropical sprue, or administration of antibiotics in tropical sprue
The metabolic improvements achieved during 5-amino-1MQ cycles can be preserved through proper nutrition, regular exercise, and stress management