What Is Anemia?

Maybe your day is so packed with things to do that you hardly have time to grab breakfast, let alone make sure you're eating right the rest of the day. Perhaps you're staying up late to get your homework finished and missing out on the sleep you need. The fact is, lots of teens are tired. And with all the demands of school and other activities, it's easy to understand why.

For some people, though, there may be another explanation for why they feel so exhausted: anemia.

To understand anemia, it helps to start with breathing. The oxygen we inhale doesn't just stop in our lungs. It's needed throughout our bodies to fuel the brain and all our other organs and tissues that allow us to function. Oxygen travels to these organs through the bloodstream — specifically in the red blood cells.

Red blood cells, or RBCs, are manufactured in the body's bone marrow and act like boats, ferrying oxygen throughout the rivers of the bloodstream. RBCs contain hemoglobin (pronounced: hee-muh-glow-bin), a protein that holds onto oxygen. To make enough hemoglobin, the body needs to have plenty of iron. We get this iron, along with the other nutrients necessary to make red blood cells, from food.

Anemia occurs when a person has fewer RBCs than normal. This can happen for three main reasons:

1. Red blood cells are being lost.
2. The body is producing RBCs slower than it should.
3. RBCs are being destroyed by the body.

Each of these causes is linked to a different type of anemia.

Blood Loss

When a small amount of blood is lost, the bone marrow is able to replace it without a person becoming anemic. But if a large amount of blood is lost over a short period of time, which can happen if someone has a serious accident or injury, for example, the bone marrow may not be able to replace the red blood cells quickly enough.

Losing a little blood over a long period of time also might lead to anemia. This can happen in girls who have heavy menstrual periods, especially if they don't get enough iron in their diets.

Iron Deficiency Anemia

Iron deficiency anemia is the most common type of anemia in U.S. teens. It occurs when a person's diet is lacking in iron. Iron deficiency — when the body's stores of iron are reduced — is the first step toward anemia. If the body's iron stores aren't replenished at this point, continuing iron deficiency can cause the body's normal hemoglobin production to slow down. When hemoglobin levels and red blood cell production drop below normal, a person is said to have anemia. Someone with anemia may appear pale and be tired all the time.

There are other nutritional reasons why someone's body may not make enough RBCs. Vitamin B12 and folic acid are also needed to make red blood cells, so it's important to get enough of these nutrients in your diet. If the bone marrow is not working properly because of an infection, chronic illness, or certain medications like chemotherapy, anemia can develop.

Hemolytic Anemia

In a person with hemolytic (pronounced: hee-muh-lih-tik) anemia, the normal lifespan of the red blood cells is shorter than normal. When blood cells die off early, the bone marrow is unable to keep up with production.

This can happen for a variety of reasons. A person may have a disorder like sickle cell anemia or spherocytosis. In other cases, the body's own immune system can cause destruction of RBCs. Antibodies might form as a reaction to certain infections or drugs that attack the RBCs by mistake.

Why Do Teens Get Anemia?

Because teens go through rapid growth spurts, they can be at risk for iron deficiency anemia. During a growth spurt, the body has a greater need for all types of nutrients, including iron, which we need to get in the foods we eat.

After puberty, girls are at more risk of iron deficiency anemia than guys are. That's because a girl needs more iron to compensate for the blood lost during her menstrual periods. Pregnancy can also cause a girl to develop anemia. And a teen on a diet to lose weight may be getting even less iron.

Vegetarians are more at risk of iron deficiency anemia than people who eat meat are. Red meat is the richest and best-absorbed source of iron. Although there is some iron in grains, vegetables, and some fruits and beans, there's less of it. And the iron in these food sources is not absorbed by the body as readily as the iron in meat.

What Are the Symptoms?

It's easy for people to overlook the symptoms of anemia because it often happens gradually over time. Looking pale can be a sign of anemia because fewer red blood cells are flowing through the blood vessels. The heart will beat faster in an effort to pump the same amount of blood and oxygen to the body, so the pulse may be faster than normal.

As anemia progresses, a person may feel tired and short of breath, especially when climbing stairs or working out. They may develop headaches. Iron deficiency, which occurs before iron deficiency anemia develops, may affect a person's ability to concentrate, learn, and remember.

Anemia is not contagious, so you cannot catch it from someone who has it.

How Is Anemia Diagnosed?

If you visit a doctor for suspected anemia, he or she will probably give you a physical examination. The doctor will also take your medical history by asking questions about any concerns and symptoms you have, your past health, your family's health (such as whether anyone in your family has anemia), any medications you're taking, any allergies you may have, and other issues.

As part of this medical history, your doctor may ask specific questions about the foods you eat. If you're a girl, the doctor may ask questions about your periods, such as how heavy the flow is, when you got your first period, how often you menstruate, and for how many days.

If your doctor suspects you are anemic, he or she will probably take a blood sample and send it to a lab for analysis. This will determine, among other things, the number, size, and shape of your red blood cells, the percentage of your blood that is made up of RBCs, and the amount of hemoglobin present in the blood. With this information, a doctor can determine if you're anemic and may order additional tests (like measuring iron levels), depending on the suspected cause of the anemia.

How Is Anemia Treated?

The treatment of anemia depends on what's causing it. If the anemia is caused by iron deficiency, your doctor will probably prescribe an iron supplement to be taken several times a day. Your doctor may do a blood test after you have been on the iron supplement. Even if the tests show that the anemia has improved, you might have to continue taking iron for several months to replenish your body's total iron stores.

Because some people become nauseated if they take an iron supplement on an empty stomach, it can help to take it with food. Vitamin C boosts iron absorption, so drink a glass of orange or grapefruit juice when you take your iron.

You can increase the chances that the iron you get from food will be absorbed by your body in other ways, too. For example, avoid drinking tea with food because a substance in tea called tannin reduces the body's ability to absorb iron found in the food or iron supplement. Milk can also interfere with iron absorption, so don't pair milk with iron-rich foods if you are concerned about getting enough iron.

Some people need more iron than others: Girls need more than guys, for example. And a girl who has heavy periods has a greater need for iron than a girl with a light flow.

To make sure you get enough iron, eat a balanced diet every day, starting with a breakfast that includes an iron source, such as an iron-fortified cereal or bread. Lean meat, raisins, spinach, eggs, dried beans, and molasses also are good sources of iron.

If someone's anemia is caused by another medical condition, doctors will work to treat the cause. People with some types of anemia will need to see a specialist, called a hematologist, who can provide the right medical care for their needs.

The good news is that for most people, anemia is easily treated. And in a few weeks they'll have their energy back!

Reviewed by: Robin Miller, MD
Date reviewed: September 2012