Anemia is a condition when there are too few red blood cells in the body.

Iron deficiency anemia (IDA) is one type of anemia where there is not enough iron in the blood to help the body make red blood cells.

The main job of red blood cells is to carry oxygen from your lungs to all the organs and tissues in your body. A red blood cell is full of a protein, called hemoglobin, which carries the oxygen. Iron is an essential part of hemoglobin. Iron is needed to help make hemoglobin and to help carry oxygen.

When people lack a sufficient amount of iron, fewer red blood cells are made and each red cell has smaller amounts of hemoglobin. As a result, people who are iron deficient can become very anemic. Iron deficiency is very common in young children because of poor intake of iron rich foods. Iron deficiency is also very common in teenage girls because of blood loss with menses.