If you're like most teens, your schedule is probably so busy you hardly have time to eat breakfast, let alone make sure you're eating right the rest of the day. And given how you run from classes to after-school sports and other activities, it may be no surprise that you've felt so tired lately. But there could be another explanation for feeling exhausted: anemia.

What Is Anemia?

Anemia basically refers to a reduction in the number of red blood cells in the body. Red blood cells are responsible for carrying oxygen to the brain and to all the other organs and tissues in the body. If your body's number of red blood cells is reduced, you have anemia. This generally happens because red blood cells are being destroyed or because they are being produced at a decreased rate.

Iron deficiency anemia, the most common type of anemia, occurs when you lose a large amount of blood from your body (for example, from bleeding or menstruating) or when you don't get enough iron from your diet. There are several stages in the development of iron deficiency anemia. First, there is simply a reduction in the iron stores of the body. As a result of low iron stores, normal hemoglobin production slows down. Hemoglobin (pronounced: hee-muh-glow-bin) is the molecule in red blood cells that carries the oxygen. Without enough iron, hemoglobin and red blood cell production drops, and anemia results. Iron deficiency anemia is the most common anemia among teens in the United States.

In addition to iron deficiency anemia, there are two other main types of anemia that often affect kids and teens:

*In aplastic (pronounced: ay-plas-tik) anemia, the cells that produce red blood cells are aplastic, or unproductive. These stem cells are located in the bone marrow, the factory for new blood production. Stem cells can become damaged due to viral infections, radiation, chemotherapy, certain drugs and toxic agents, and other factors.

*In hemolytic (pronounced: hee-muh-li-tik) anemia, red blood cells are destroyed prematurely. This can be caused by a variety of problems, including congenital disorders such as thalassemia or sickle cell anemia. In other cases, the body's own antibodies can cause destruction of red blood cells. These antibodies can be formed as a reaction to certain infections or drugs.

Why Do Teens Get Anemia?

Anemia is not a contagious disease that you can catch from other people. Teens are more prone to get iron deficiency anemia because they undergo rapid growth spurts, when the body has a greater need for nutrients, including iron.

Teen girls are at particular risk for iron deficiency anemia because of a combination of factors, according to Ann Bruner, MD, Assistant Professor of Medicine at Johns Hopkins University School of Medicine. It's estimated that 9% of 12- to 15-year-old girls are iron deficient and 2% have iron deficiency anemia. Among 18- to 19-year-old girls, 11% are iron deficient and 3% are anemic.

First, teen girls lose more iron than boys do because they menstruate. If a girl's period is heavy and lasts for more than 5 days, she has greater iron needs than a girl who has a light flow. And second, many teen girls are picky eaters, go on diets to lose weight, or become vegetarians, which makes it more difficult to get iron from food sources. It's often hard to be on a restrictive diet and get enough iron.

"Red meat is one of the mainstays for iron intake," says Maureen Edelson, MD, a pediatric hematologist (a doctor who specializes in blood and blood disorders) at duPont Hospital for Children in Wilmington, Delaware. That's because red meat is the richest and best-absorbed source of iron. There is iron in grains, vegetables, and some fruits and beans, but it's not absorbed as well, and there's less of it. Poor eating habits can cause iron deficiency anemia, but when you combine them with blood loss from menstruation, it's even easier for girls to lose more iron than they're taking in. The result is an iron deficiency in the body that, if not detected and treated, will result in anemia.

Other things that can put any teen at risk for iron deficiency anemia include pregnancy, ulcers or intestinal diseases such as ulcerative colitis, or other problems that make it hard for a teen to absorb iron from food.

What Are the Symptoms?

No matter the cause, the classic symptom of iron deficiency anemia is fatigue. Teens with other types of anemia may develop an array of other symptoms, such as jaundice, which is a yellowing of the skin and whites of the eyes, swelling of the lymph nodes, or bone pain. (Bone pain often occurs when anemia is the result of bone marrow replacement due to leukemia cells).

Iron deficiency, which occurs prior to the development of anemia, causes few symptoms, and the symptoms can easily go unnoticed. They may include fatigue, difficulty concentrating, rapid exhaustion when working out, and memory problems. "But these are pretty common symptoms in the general population - even for people without iron deficiency," Dr. Bruner says. It's not until a teen develops severe anemia - which can take years - that the symptoms become more dramatic and noticeable. These symptoms include pale skin, paleness of the lining of the lower eyelids, a rapid heart rate, and shortness of breath when climbing stairs or working out because the heart has to work harder to provide oxygen to the rest of the body.

How Is Anemia Diagnosed?

If your doctor suspects you are anemic, he or she will probably take a blood sample from your arm and send it to a lab for a complete blood count (CBC). This test will determine, among other things, the number, size, and shape of your red blood cells and the percentage of your blood that is made up of red blood cells. With this information, your doctor can determine if you are anemic.

Only a very specific blood test called serum ferritin can determine if your iron stores are low before anemia develops.

"If a teen has anemia despite good nutrition, the doctor may look for blood loss from the gut," Dr. Edelson says. In that case, the doctor will ask you if your stools are black or if you have abdominal pain, as well as perform a stool test to see if there is any blood. Your doctor will also ask you about the foods you eat; whether you're on a special diet, such as vegetarian or a weight-loss program, and for how long; if you participate in any endurance exercise, such as long-distance running; and characteristics of your periods such as how heavy the flow is, when you got your first period, how often you menstruate, and for how many days. You should also mention if you've ever been told that you were iron deficient or whether any member of your family has anemia.

How Is Anemia Treated?

The treatment of anemia depends on the cause. If the anemia is caused by iron deficiency, your doctor will prescribe an iron supplement that you should take several times a day for 6 to 8 weeks. Some teens become nauseated if they take the iron supplement on an empty stomach so it's best to take it with orange or grapefruit juice - the vitamin C in the juice boosts iron absorption - and a piece of toast, some crackers, or a bagel. Also, you should avoid drinking tea with food because a substance in tea called tannin reduces your body's ability to absorb iron found in the food or supplement.

To make sure your iron stores are optimal, you should eat a balanced diet every day, including a breakfast that includes an iron source, such as lean meat, raisins, spinach, eggs, fortified cereals or breads, or molasses.

Reviewed by: Maureen Edelson, MD, and Rita Meek, MD
Date reviewed: August 2001