what does b12 deficiency mean
Having vitamin B12 deficiency means that your body does not have enough of this vitamin. You need B12 to make red blood cells, which carry oxygen through your body. Not having enough B12 can lead to anemia, which means your body does not have enough red blood cells to do the job. This can make you feel weak and tired.Vitamin B12 deficiency can cause damage to your nerves and can affect memory and thinking.his can happen if: 1  You have pernicious anemia. 2  In this anemia, your body destroys the cells in your stomach that help you absorb vitamin B12. 3  You have had surgery to remove part of the stomach or the last part of your small intestine, called the ileum.