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What Is Anemia?

Lots of teens are tired. With all the demands of school and other activities, it's easy to understand why. For some people, though, there's another explanation for why they feel so exhausted: anemia.

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

Red blood cells, (RBCs for short) act like boats, ferrying oxygen through 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.

hemoglobin illustration

Anemia is when a person has fewer red blood cells than normal. This can happen for three main reasons:

  1. Red blood cells are being lost.
  2. The body is producing red blood cells more slowly than it should.
  3. The body is destroying red blood cells.

Each of these causes is linked to a different type of anemia. When someone has anemia, you might hear people say they are "anemic."

Blood Loss

Red blood cells are made in the bone marrow. When someone loses a small amount of blood, like from a cut, the bone marrow is able to replace it without the person becoming anemic. But if a large amount of blood is lost over a short period of time (like after a serious accident), 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 happens 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.

The body may not make enough RBCs for other nutritional reasons. For instance, our bodies need vitamin B12 and folic acid to make red blood cells, so it's important to get enough of these nutrients in food. People also can develop anemia if the bone marrow is not working properly because of an infection, chronic illness, or treatments like chemotherapy.

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 can't 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 destroy red blood cells.

Why 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.

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.

Symptoms of Anemia

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.

What Doctors Do

If you see a doctor because you think you have anemia, your doctor will probably give you a physical examination. The doctor will take your medical history by asking questions about things like problems you're noticing, your past health, and your family's health.

Your doctor may have questions about the foods you eat. If you're a girl, the doctor may ask 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 thinks you might be anemic, he or she will probably take a blood sample and send it to a lab for analysis.

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 follow-up blood test after you've been taking the supplement for a while. Even if the tests show that the anemia has improved, you might have to keep taking iron for several months to build back your body's iron stores.

Getting Enough Iron

Some people feel sick if they take an iron supplement on an empty stomach. It can help to take iron supplements 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 or supplements will be absorbed by your body in other ways. One tip is not to drink tea with food. A substance in tea called tannin reduces the body's ability to absorb iron. Milk can also interfere with iron absorption, so don't drink 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, 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

Kids Health

