Anemia is a deficiency in red blood cells and/or the nutrients necessary to make red blood cells. There are six different kinds of anemia, each having their own characteristics and traits. In the field of oncology, the two most common forms are aplastic anemia (insufficient red blood cells) and iron deficient anemia (causing a decreased hemoglobin level). Anemia can be caused by both the disease and treatment. These supplements are the nutritional building blocks your body will need to improve your red blood cell count and hemoglobin level.