What causes vitamin B12 deficiency anemia?
Most people get more than enough B12 from eating meat, eggs, milk, and cheese. Normally, the vitamin is absorbed by your digestive system—your stomach and intestines. Vitamin B12 deficiency anemia usually happens when the digestive system is not able to absorb the vitamin. This can happen if: • You have pernicious anemia . In this anemia, your body destroys the cells in your stomach that help you absorb vitamin B12. • You have had surgery to remove part of the stomach or the last part of your small intestine, called the ileum . This includes some types of surgery used to help very overweight people lose weight. • You have problems with the way your body digests food, such as sprue (also called celiac disease), Crohn’s disease , bacteria growth in the small intestine, or a parasite . • You take medicine for heartburn and ulcers for a long time. This anemia can also happen if you don’t eat enough foods with B12, but this is rare. People who eat a vegan diet and older adults who don’t eat
