Anemia is a condition that affects your red blood cells. Your red blood cells carry oxygen from your lungs to the rest of your body. Hemoglobin is the protein in red blood cells that allows them to carry oxygen. Your body needs iron in order to make hemoglobin.  People who have anemia don’t have enough hemoglobin. The most common cause of anemia is when your body doesn’t make enough hemoglobin because it doesn’t have enough iron. This is called iron deficiency anemia.  Another common type of anemia is when your body doesn’t have enough red blood cells, but the red blood cells you do have are normal in size. This is called normocytic (say: “normo-sit-tic”) anemia.