Our blood contains several different types of cells. The ones we have the most of are the red blood cells. These cells absorb oxygen in the lungs and distribute it throughout the body. They contain hemoglobin, a red pigment that carries oxygen to the tissues and carries away the waste material, carbon dioxide. When there is a decreased amount of hemoglobin available in the red blood cells, making the blood less able to carry the amount of oxygen necessary for all the cells in the body to function and grow, the condition is called anemia.
Anemia may occur for any of the following reasons:
Young children most commonly become anemic when they fail to get enough iron in their diet. Iron is necessary for the production of hemoglobin. This iron deficiency causes a decrease in the amount of hemoglobin in the red blood cells. A young infant may get iron-deficiency anemia if he starts drinking cow's milk too early, particularly if he is not given an iron supplement or food with iron. The deficiency occurs because cow's milk contains very little iron and the small amount present is poorly absorbed through the intestines into the body. In addition, cow's milk given to an infant under six months of age can cause irritation of the bowel and small amounts of blood loss. This results in a decrease in the number of red blood cells, which can cause anemia.
Other nutritional deficiencies, such as lack of folic acid, can cause anemia, but this is very rare. It is probably most often seen in children fed goat's milk, which contains very little folic acid.
Anemia at any age can be caused by excessive blood loss. In rare cases, the blood does not clot properly, and a newborn infant may bleed heavily from his circumcision or minor injury, and become anemic. Because vitamin K promotes blood clotting and is often lacking in newborns, an injection of this vitamin generally is given right after birth.
Sometimes the red cells are prone to being easily destroyed. This is called hemolytic anemia, and can result from disturbances on the surface of the red cells or other abnormalities in or outside the cells. Certain enzyme deficiencies also can alter the function of the red blood cells, increasing their susceptibility to destruction.
A severe condition involving an abnormal structure of hemoglobin, seen most often in children of black African heritage, is called sickle-cell anemia. This disorder can be very severe and is associated with frequent "crises" and often repeated hospitalizations. Children with sickle-cell anemia may have unexplained fever or swelling of the hands and feet as infants, and they are extremely susceptible to infection. If there is a history of sickle-cell anemia in your family, make sure your child is tested for it.