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What Is Iron-Deficiency Anemia?

Iron-deficiency anemia is a common, easily treated condition that occurs if you don't have enough iron in your body. Low iron levels usually are due to blood loss, poor diet, or an inability to absorb enough iron from food.

Overview

Iron-deficiency anemia is a common type of anemia. The term "anemia" usually refers to a condition in which your blood has a lower than normal number of red blood cells. Red blood cells carry oxygen and remove carbon dioxide (a waste product) from your body.

Anemia also can occur if your red blood cells don't contain enough hemoglobin (HEE-muh-glow-bin). Hemoglobin is an iron-rich protein that carries oxygen from the lungs to the rest of the body.

Iron-deficiency anemia usually develops over time if your body doesn't have enough iron to build healthy red blood cells. Without enough iron, your body starts using the iron it has stored. Soon, the stored iron gets used up.

After the stored iron is gone, your body makes fewer red blood cells. The red blood cells it does make have less hemoglobin than normal.

Iron-deficiency anemia can cause fatigue (tiredness), shortness of breath, chest pain, and other symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in children, and other complications.

Infants and young children and women are the two groups at highest risk for iron-deficiency anemia.

Outlook

Doctors usually can successfully treat iron-deficiency anemia. Treatment will depend on the cause and severity of the condition. Treatments may include dietary changes, medicines, and surgery.

Severe iron-deficiency anemia may require treatment in a hospital, blood transfusions, iron injections, or intravenous iron therapy.




What Causes Iron-Deficiency Anemia?

Not having enough iron in your body causes iron-deficiency anemia. Lack of iron usually is due to blood loss, poor diet, or an inability to absorb enough iron from food.

Blood Loss

When you lose blood, you lose iron. If you don't have enough iron stored in your body to make up for the lost iron, you'll develop iron-deficiency anemia.

In women, long or heavy menstrual periods or bleeding fibroids in the uterus may cause low iron levels. Blood loss that occurs during childbirth is another cause of low iron levels in women.

Internal bleeding (bleeding inside the body) also may lead to iron-deficiency anemia. This type of blood loss isn't always obvious, and it may occur slowly. Some causes of internal bleeding are:

  • A bleeding ulcer, colon polyp, or colon cancer
  • Regular use of aspirin or other pain medicines, such as nonsteroidal anti-inflammatory drugs (for example, ibuprofen and naproxen)
  • Urinary tract bleeding

Blood loss from severe injuries, surgery, or frequent blood drawings also can cause iron-deficiency anemia.

Poor Diet

The best sources of iron are meat, poultry, fish, and iron-fortified foods (foods that have iron added). If you don't eat these foods regularly, or if you don't take an iron supplement, you're more likely to develop iron-deficiency anemia.

Vegetarian diets can provide enough iron if you eat the right foods. For example, good nonmeat sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark green leafy vegetables.

During some stages of life, such as pregnancy and childhood, it may be hard to get enough iron in your diet. This is because your need for iron increases during these times of growth and development.

Inability To Absorb Enough Iron

Even if you have enough iron in your diet, your body may not be able to absorb it. This can happen if you have intestinal surgery (such as gastric bypass) or a disease of the intestine (such as Crohn's disease or celiac disease).

Prescription medicines that reduce acid in the stomach also can interfere with iron absorption.




Who Is at Risk for Iron-Deficiency Anemia?

Infants and Young Children

Infants and young children need a lot of iron to grow and develop. The iron that full-term infants have stored in their bodies is used up in the first 4 to 6 months of life.

Premature and low-birth-weight babies (weighing less than 5.5 pounds) are at even greater risk for iron-deficiency anemia. These babies don't have as much iron stored in their bodies as larger, full-term infants.

Iron-fortified baby food or iron supplements, when used properly, can help prevent iron-deficiency anemia in infants and young children. Talk with your child's doctor about your child's diet.

Young children who drink a lot of cow's milk may be at risk for iron-deficiency anemia. Milk is low in iron, and too much milk may take the place of iron-rich foods in the diet. Too much milk also may prevent children's bodies from absorbing iron from other foods.

Children who have lead in their blood also may be at risk for iron-deficiency anemia. Lead can interfere with the body's ability to make hemoglobin. Lead may get into the body from breathing in lead dust, eating lead in paint or soil, or drinking water that contains lead.

Teens

Teens are at risk for iron-deficiency anemia if they're underweight or have chronic (ongoing) illnesses. Teenage girls who have heavy periods also are at increased risk for the condition.

Women

Women of childbearing age are at higher risk for iron-deficiency anemia because of blood loss during their monthly periods. About 1 in 5 women of childbearing age has iron-deficiency anemia.

Pregnant women also are at higher risk for the condition because they need twice as much iron as usual. The extra iron is needed for increased blood volume and for the fetus' growth.

About half of all pregnant women develop iron-deficiency anemia. The condition can increase a pregnant woman's risk for a premature or low-birth-weight baby.

Adults Who Have Internal Bleeding

Adults who have internal bleeding, such as intestinal bleeding, can develop iron-deficiency anemia due to blood loss. Certain conditions, such as colon cancer and bleeding ulcers, can cause blood loss. Some medicines, such as aspirin, also can cause internal bleeding.

Other At-Risk Groups

People who get kidney dialysis treatment may develop iron-deficiency anemia. This is because blood is lost during dialysis. Also, the kidneys are no longer able to make enough of a hormone that the body needs to produce red blood cells.

People who have gastric bypass surgery also may develop iron-deficiency anemia. This type of surgery can prevent the body from absorbing enough iron.

Certain eating patterns or habits may put you at higher risk for iron-deficiency anemia. This can happen if you:

  • Follow a diet that excludes meat and fish, which are the best sources of iron. However, vegetarian diets can provide enough iron if you eat the right foods. For example, good nonmeat sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark green leafy vegetables.
  • Eat poorly because of money, social, health, or other problems.
  • Follow a very low-fat diet over a long time. Some higher fat foods, like meat, are the best sources of iron.
  • Follow a high-fiber diet. Large amounts of fiber can slow the absorption of iron.



What Are the Signs and Symptoms of Iron-Deficiency Anemia?

The signs and symptoms of iron-deficiency anemia depend on its severity. Mild to moderate iron-deficiency anemia may have no signs or symptoms.

When signs and symptoms do occur, they can range from mild to severe. Many of the signs and symptoms of iron-deficiency anemia apply to all types of anemia.

Signs and Symptoms of Anemia

The most common symptom of all types of anemia is fatigue (tiredness). Fatigue occurs because your body doesn't have enough red blood cells to carry oxygen to its many parts.

Also, the red blood cells your body makes have less hemoglobin than normal. Hemoglobin is an iron-rich protein in red blood cells. It helps red blood cells carry oxygen from the lungs to the rest of the body.

Anemia also can cause shortness of breath, dizziness, headache, coldness in your hands and feet, pale skin, chest pain, weakness, and fatigue (tiredness).

If you don't have enough hemoglobin-carrying red blood cells, your heart has to work harder to move oxygen-rich blood through your body. This can lead to irregular heartbeats called arrhythmias (ah-RITH-me-ahs), a heart murmur, an enlarged heart, or even heart failure.

In infants and young children, signs of anemia include poor appetite, slowed growth and development, and behavioral problems.

Signs and Symptoms of Iron Deficiency

Signs and symptoms of iron deficiency may include brittle nails, swelling or soreness of the tongue, cracks in the sides of the mouth, an enlarged spleen, and frequent infections.

People who have iron-deficiency anemia may have an unusual craving for nonfood items, such as ice, dirt, paint, or starch. This craving is called pica (PI-ka or PE-ka).

Some people who have iron-deficiency anemia develop restless legs syndrome (RLS). RLS is a disorder that causes a strong urge to move the legs. This urge to move often occurs with strange and unpleasant feelings in the legs. People who have RLS often have a hard time sleeping.

Iron-deficiency anemia can put children at greater risk for lead poisoning and infections.

Some signs and symptoms of iron-deficiency anemia are related to the condition's causes. For example, a sign of intestinal bleeding is bright red blood in the stools or black, tarry-looking stools.

Very heavy menstrual bleeding, long periods, or other vaginal bleeding may suggest that a woman is at risk for iron-deficiency anemia.




How Is Iron-Deficiency Anemia Diagnosed?

Your doctor will diagnose iron-deficiency anemia based on your medical history, a physical exam, and the results from tests and procedures.

Once your doctor knows the cause and severity of the condition, he or she can create a treatment plan for you.

Mild to moderate iron-deficiency anemia may have no signs or symptoms. Thus, you may not know you have it unless your doctor discovers it from a screening test or while checking for other problems.

Specialists Involved

Primary care doctors often diagnose and treat iron-deficiency anemia. These doctors include pediatricians, family doctors, gynecologists/obstetricians, and internal medicine specialists.

A hematologist (a blood disease specialist), a gastroenterologist (a digestive system specialist), and other specialists also may help treat iron-deficiency anemia.

Medical History

Your doctor will ask about your signs and symptoms and any past problems you've had with anemia or low iron. He or she also may ask about your diet and whether you're taking any medicines.

If you're a woman, your doctor may ask whether you might be pregnant.

Physical Exam

Your doctor will do a physical exam to look for signs of iron-deficiency anemia. He or she may:

  • Look at your skin, gums, and nail beds to see whether they're pale
  • Listen to your heart for rapid or irregular heartbeats
  • Listen to your lungs for rapid or uneven breathing
  • Feel your abdomen to check the size of your liver and spleen
  • Do a pelvic and rectal exam to check for internal bleeding

Diagnostic Tests and Procedures

Many tests and procedures are used to diagnose iron-deficiency anemia. They can help confirm a diagnosis, look for a cause, and find out how severe the condition is.

Complete Blood Count

Often, the first test used to diagnose anemia is a complete blood count (CBC). The CBC measures many parts of your blood.

This test checks your hemoglobin and hematocrit (hee-MAT-oh-crit) levels. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen to the body. Hematocrit is a measure of how much space red blood cells take up in your blood. A low level of hemoglobin or hematocrit is a sign of anemia.

The normal range of these levels varies in certain racial and ethnic populations. Your doctor can explain your test results to you.

The CBC also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal results may be a sign of infection, a blood disorder, or another condition.

Finally, the CBC looks at mean corpuscular (kor-PUS-kyu-lar) volume (MCV). MCV is a measure of the average size of your red blood cells. The results may be a clue as to the cause of your anemia. In iron-deficiency anemia, for example, red blood cells usually are smaller than normal.

Other Blood Tests

If the CBC results confirm you have anemia, you may need other blood tests to find out what's causing the condition, how severe it is, and the best way to treat it.

Reticulocyte count. This test measures the number of reticulocytes (re-TIK-u-lo-sites) in your blood. Reticulocytes are young, immature red blood cells. Over time, reticulocytes become mature red blood cells that carry oxygen throughout your body.

A reticulocyte count shows whether your bone marrow is making red blood cells at the correct rate.

Peripheral smear. For this test, a sample of your blood is examined under a microscope. If you have iron-deficiency anemia, your red blood cells will look smaller and paler than normal.

Tests to measure iron levels. These tests can show how much iron has been used from your body's stored iron. Tests to measure iron levels include:

  • Serum iron. This test measures the amount of iron in your blood. The level of iron in your blood may be normal even if the total amount of iron in your body is low. For this reason, other iron tests also are done.
  • Serum ferritin. Ferritin is a protein that helps store iron in your body. A measure of this protein helps your doctor find out how much of your body's stored iron has been used.
  • Transferrin level, or total iron-binding capacity. Transferrin is a protein that carries iron in your blood. Total iron-binding capacity measures how much of the transferrin in your blood isn't carrying iron. If you have iron-deficiency anemia, you'll have a high level of transferrin that has no iron.

Other tests. Your doctor also may recommend tests to check your hormone levels, especially your thyroid hormone. You also may have a blood test for a chemical called erythrocyte protoporphyrin. This chemical is a building block for hemoglobin.

Children also may be tested for the level of lead in their blood. Lead can make it hard for the body to produce hemoglobin.

Tests and Procedures for Gastrointestinal Blood Loss

To check whether internal bleeding is causing your iron-deficiency anemia, your doctor may suggest a fecal occult blood test. This test looks for blood in the stools and can detect bleeding in the intestines.

If the test finds blood, you may have other tests and procedures to find the exact spot of the bleeding. These tests and procedures may look for bleeding in the stomach, upper intestines, colon, or pelvic organs.




How Is Iron-Deficiency Anemia Treated?

Treatment for iron-deficiency anemia will depend on its cause and severity. Treatments may include dietary changes and supplements, medicines, and surgery.

Severe iron-deficiency anemia may require a blood transfusion, iron injections, or intravenous (IV) iron therapy. Treatment may need to be done in a hospital.

The goals of treating iron-deficiency anemia are to treat its underlying cause and restore normal levels of red blood cells, hemoglobin, and iron.

Dietary Changes and Supplements

Iron

You may need iron supplements to build up your iron levels as quickly as possible. Iron supplements can correct low iron levels within months. Supplements come in pill form or in drops for children.

Large amounts of iron can be harmful, so take iron supplements only as your doctor prescribes. Keep iron supplements out of reach from children. This will prevent them from taking an overdose of iron.

Iron supplements can cause side effects, such as dark stools, stomach irritation, and heartburn. Iron also can cause constipation, so your doctor may suggest that you use a stool softener.

Your doctor may advise you to eat more foods that are rich in iron. The best source of iron is red meat, especially beef and liver. Chicken, turkey, pork, fish, and shellfish also are good sources of iron.

The body tends to absorb iron from meat better than iron from nonmeat foods. However, some nonmeat foods also can help you raise your iron levels. Examples of nonmeat foods that are good sources of iron include:

  • Iron-fortified breads and cereals
  • Peas; lentils; white, red, and baked beans; soybeans; and chickpeas
  • Tofu
  • Dried fruits, such as prunes, raisins, and apricots
  • Spinach and other dark green leafy vegetables
  • Prune juice

The Nutrition Facts labels on packaged foods will show how much iron the items contain. The amount is given as a percentage of the total amount of iron you need every day.

Vitamin C

Vitamin C helps the body absorb iron. Good sources of vitamin C are vegetables and fruits, especially citrus fruits. Citrus fruits include oranges, grapefruits, tangerines, and similar fruits. Fresh and frozen fruits, vegetables, and juices usually have more vitamin C than canned ones.

If you're taking medicines, ask your doctor or pharmacist whether you can eat grapefruit or drink grapefruit juice. Grapefruit can affect the strength of a few medicines and how well they work.

Other fruits rich in vitamin C include kiwi fruit, strawberries, and cantaloupes.

Vegetables rich in vitamin C include broccoli, peppers, Brussels sprouts, tomatoes, cabbage, potatoes, and leafy green vegetables like turnip greens and spinach.

Treatment To Stop Bleeding

If blood loss is causing iron-deficiency anemia, treatment will depend on the cause of the bleeding. For example, if you have a bleeding ulcer, your doctor may prescribe antibiotics and other medicines to treat the ulcer.

If a polyp or cancerous tumor in your intestine is causing bleeding, you may need surgery to remove the growth.

If you have heavy menstrual flow, your doctor may prescribe birth control pills to help reduce your monthly blood flow. In some cases, surgery may be advised.

Treatments for Severe Iron-Deficiency Anemia

Blood Transfusion

If your iron-deficiency anemia is severe, you may get a transfusion of red blood cells. A blood transfusion is a safe, common procedure in which blood is given to you through an IV line in one of your blood vessels. A transfusion requires careful matching of donated blood with the recipient's blood.

A transfusion of red blood cells will treat your anemia right away. The red blood cells also give a source of iron that your body can reuse. However, a blood transfusion is only a short-term treatment. Your doctor will need to find and treat the cause of your anemia.

Blood transfusions are usually reserved for people whose anemia puts them at a higher risk for heart problems or other severe health issues.

For more information, go to the Health Topics Blood Transfusion article.

Iron Therapy

If you have severe anemia, your doctor may recommend iron therapy. For this treatment, iron is injected into a muscle or an IV line in one of your blood vessels.

IV iron therapy presents some safety concerns. It must be done in a hospital or clinic by experienced staff. Iron therapy usually is given to people who need iron long-term but can't take iron supplements by mouth. This therapy also is given to people who need immediate treatment for iron-deficiency anemia.




How Can Iron-Deficiency Anemia Be Prevented?

Eating a well-balanced diet that includes iron-rich foods may help you prevent iron-deficiency anemia.

Taking iron supplements also may lower your risk for the condition if you're not able to get enough iron from food. Large amounts of iron can be harmful, so take iron supplements only as your doctor prescribes.

For more information about diet and supplements, go to "How Is Iron-Deficiency Anemia Treated?"

Infants and young children and women are the two groups at highest risk for iron-deficiency anemia. Special measures can help prevent the condition in these groups.

Infants and Young Children

A baby's diet can affect his or her risk for iron-deficiency anemia. For example, cow's milk is low in iron. For this and other reasons, cow's milk isn't recommended for babies in their first year. After the first year, you may need to limit the amount of cow's milk your baby drinks.

Also, babies need more iron as they grow and begin to eat solid foods. Talk with your child's doctor about a healthy diet and food choices that will help your child get enough iron.

Your child's doctor may recommend iron drops. However, giving a child too much iron can be harmful. Follow the doctor's instructions and keep iron supplements and vitamins away from children. Asking for child-proof packages for supplements can help prevent overdosing in children.

Because recent research supports concerns that iron deficiency during infancy and childhood can have long-lasting, negative effects on brain health, the American Academy of Pediatrics recommends testing all infants for anemia at 1 year of age.

Women and Girls

Women of childbearing age may be tested for iron-deficiency anemia, especially if they have:

  • A history of iron-deficiency anemia
  • Heavy blood loss during their monthly periods
  • Other risk factors for iron-deficiency anemia

The Centers for Disease Control and Prevention (CDC) has developed guidelines for who should be screened for iron deficiency, and how often:

  • Girls aged 12 to 18 and women of childbearing age who are not pregnant: Every 5 to 10 years.
  • Women who have risk factors for iron deficiency: Once a year.
  • Pregnant women: At the first prenatal visit.

For pregnant women, medical care during pregnancy usually includes screening for anemia. Also, your doctor may prescribe iron supplements or advise you to eat more iron-rich foods. This not only will help you avoid iron-deficiency anemia, but also may lower your risk of having a low-birth-weight baby.




Living With Iron-Deficiency Anemia

If you have iron-deficiency anemia, get ongoing care to make sure your iron levels are improving. At your checkups, your doctor may change your medicines or supplements. He or she also may suggest ways to improve your diet.

Take iron supplements only with your doctor's approval, and only as he or she prescribes. It's possible to have too much iron in your body (a condition called iron overload). Too much iron in your body can damage your organs.

You may have fatigue (tiredness) and other symptoms of iron-deficiency anemia until your iron levels return to normal, which can take months. Tell your doctor if you have any new symptoms or if your symptoms get worse.




Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

Researchers have learned a lot about anemia and other blood diseases and conditions over the years. That knowledge has led to advances in medical care.

Many questions remain about blood diseases and conditions, including iron-deficiency anemia. The NHLBI continues to support research aimed at learning more about these illnesses.

For example, NHLBI-supported research on iron-deficiency anemia includes studies that explore:

  • Ways to prevent iron deficiency among infants, such as giving iron supplements at various stages of development
  • The causes of unexplained anemia in older people
  • The lifespan of red blood cells in both younger and older adults and their role in anemia

Much of this research depends on the willingness of volunteers to take part in clinical trials.

Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions. For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you can gain access to new treatments before they're widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don't directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You'll learn about treatments and tests you may receive, and the benefits and risks they may pose. You'll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you'll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to iron-deficiency anemia, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

For more information about clinical trials for children, visit the NHLBI's Children and Clinical Studies Web page.




Links to Other Information About Iron-Deficiency Anemia

NHLBI Resources

Non-NHLBI Resources

Clinical Trials

 
March 26, 2014 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.

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