RELATED STORIES • Craving and chewing ice: A sign of anemia? HEART & BLOOD Anemia • Anemia • Aplastic anemia • Iron deficiency anemia • Sickle cell anemia • Vitamin deficiency anemia

Note: All links within content go to MayoClinic.com

Having iron deficiency anemia may cause you to feel tired and often look pale. It's a common type of anemia — a condition in which blood is lacking healthy red blood cells, which carry oxygen to tissues. Oxygenated blood gives your body energy and your skin a healthy color.

As the name implies, iron deficiency anemia is due to insufficient iron. Your body needs the element iron to make hemoglobin, a substance in red blood cells that enables them to carry oxygen.

Iron deficiency anemia is common, especially in women. One in five women and half of all pregnant women are iron deficient. Lack of iron in your diet is one cause of iron deficiency anemia, but there are other causes as well.

You can usually correct iron deficiency anemia with iron supplementation. Sometimes, other treatments are necessary if you're bleeding internally.

In general, anemia causes extreme fatigue, pale skin, weakness, shortness of breath, lightheadedness, and often cold hands and feet.

Signs and symptoms of iron deficiency anemia in particular may include:

• Inflammation or soreness of your tongue
• Brittle nails
• Unusual cravings for non-nutritive substances, such as ice, dirt or pure starch
• Headache
• Poor appetite, especially in infants and children with iron deficiency anemia

Some people with iron deficiency anemia experience restless legs syndrome — an uncomfortable tingling or crawling feeling in your legs that's generally relieved by moving them.

If you or your child develops signs and symptoms that suggest iron deficiency anemia, see your doctor. Initially, iron deficiency anemia can be so mild that it goes unnoticed. But as the body becomes more deficient in iron and anemia progresses, the signs and symptoms intensify.

Your blood consists of liquid called plasma and three types of blood cells:

• White blood cells. These blood cells fight infection.
• Platelets. These blood cells help your blood clot after a cut.
• Red blood cells (erythrocytes). These blood cells carry oxygen from your lungs, by way of your bloodstream, to your brain and the other organs and tissues. Your body needs a supply of oxygenated blood to function. Oxygenated blood helps give your body its energy and your skin a healthy glow.

Red blood cells contain hemoglobin, an iron-rich substance that gives blood its red color. Hemoglobin enables red blood cells to carry oxygen from your lungs to all parts of your body.

Red blood cells are manufactured in your bone marrow — a red, spongy material located within the cavities of many of your large bones, such as your pelvic bones. Your bone marrow needs iron, along with vitamins, to produce hemoglobin and red blood cells. Your body gets vitamins and iron from the foods you eat. Your body also recycles iron from old red blood cells.

You can be mildly deficient in iron and not develop anemia. Iron deficiency leads to anemia when the body lacks sufficient iron to make adequate hemoglobin. Without enough hemoglobin, your red blood cells are smaller and paler than normal, and they can't carry adequate oxygen to your tissues.

Causes of iron deficiency anemia include:

• Blood loss. Blood contains iron within red blood cells. If you lose blood, you lose some iron. Women with heavy periods are at risk of iron deficiency anemia because they lose a lot of blood during menstruation. Slow, chronic blood loss from a source within the body — such as a peptic ulcer, a hiatal hernia, a kidney or bladder tumor, a colon polyp, colorectal cancer, or uterine fibroids — can cause iron deficiency anemia. Gastrointestinal bleeding from regular use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) or bleeding from hemorrhoids also can be a source of iron loss and anemia. While not common in the United States, hookworm infestation can cause blood loss. Blood lost from within the body may show up in your urine or stools, producing black or bloody stools. Inform your doctor if you notice blood in your urine or stools.

• A lack of iron in your diet. Your body regularly gets iron from the foods you eat. If you consume too little iron, over time your body can become iron deficient. Examples of iron-rich foods include meat, eggs and whole-grain or iron-fortified foods. Infants and children need iron from their diet, too.
• An inability to absorb iron. Iron from food is absorbed into your bloodstream in your small intestine. An intestinal disorder such as Crohn's disease or celiac disease, which affects your intestine's ability to absorb nutrients from digested food, can lead to iron deficiency anemia. If part of your small intestine has been bypassed or removed surgically, that may affect your ability to absorb iron and other nutrients. Some medications can interfere with iron absorption. For example, regular use of prescription-strength stomach acid blockers called proton pump inhibitors may lead to iron deficiency anemia, although this is rare. Your body needs stomach acid, which these products suppress, to convert dietary iron into a form that can readily be absorbed by the small intestine.

• Pregnancy. Without iron supplementation, iron deficiency anemia occurs in many pregnant women because their iron stores need to serve their own increased blood volume as well as be a source of hemoglobin for the growing fetus. A fetus needs iron to develop red blood cells, blood vessels and muscle.

These factors may increase the risk of iron deficiency anemia:

• Heavy menstrual periods
• Pregnancy
• A diet consistently low in iron
• A known or hidden source of bleeding within your body, such as an ulcer, a bleeding tumor, a uterine fibroid, a colon polyp, colorectal cancer, gastrointestinal bleeding or hemorrhoids

These groups of people may be at higher risk:

• Women. Because their bodies store less iron and because they lose blood during menstruation, women in general are at greater risk of iron deficiency anemia.
• Infants and children. Infants who don't get enough iron in their milk or formula may risk deficiency. Children need extra iron during growth spurts, because iron is also important for muscle development. If your child isn't eating a healthy, varied diet, he or she may be at risk of anemia.
• Vegetarians. Because vegetarians don't eat meat, they're at greater risk of iron deficiency anemia. Iron that comes from grains and vegetables isn't absorbed by the body as well as is iron that comes from meat.

In healthy men and postmenopausal women, iron deficiency usually points to bleeding somewhere in the gastrointestinal tract.

Donating blood — a source of blood loss — usually isn't a risk factor for iron deficiency anemia. However, some people first learn their hemoglobin is low, which indicates anemia, when they go to donate blood. Low hemoglobin may be a temporary problem remedied by eating more iron-rich foods. It may also be a warning sign of blood loss in your body. If you're told that you can't donate blood because of low hemoglobin, ask your doctor whether you should be concerned.

See your doctor or your child's doctor if you think you or your child may be anemic. Iron deficiency anemia isn't something to self-diagnose or treat. Take iron supplements only under a doctor's supervision. Overloading the body with iron can be dangerous. Excess iron accumulation can damage your liver, among other complications.

Once you've had iron deficiency anemia, it can recur. You may need follow-up visits to your doctor.

Doctors diagnose iron deficiency anemia mainly through blood tests. These may include tests to examine the size and color of your red blood cells. With iron deficiency anemia, red blood cells are smaller and paler in color than normal.

Your doctor will check your hematocrit — the percentage of your blood volume made up by red blood cells and hemoglobin. Normal levels of hemoglobin range between 11.1 and 15.0 grams per deciliter (g/dL). Your hemoglobin is low if:

• For women, it's less than 10 g/dL
• For men, it's less than 12 g/dL

In addition, blood tests for iron deficiency anemia typically include a measurement of ferritin, a protein that helps store iron in the body. A low level of ferritin usually indicates a low level of iron.

Additional diagnostic tests
If your blood work indicates iron deficiency anemia, your doctor may order additional tests to identify an underlying cause. If your doctor suspects a source of bleeding within your body, you may need to have your stools tested for traces of blood. Blood in the stools is often an indicator of internal bleeding.

You may need these additional diagnostic tests:

• Endoscopy. Doctors often check for bleeding from a hiatal hernia, bleeding ulcers and stomach bleeding with the aid of endoscopy. In this procedure, a thin, lighted tube equipped with a video camera is passed down your throat to your stomach. This allows your doctor to view your esophagus — the tube that runs from your mouth to your stomach — and your upper stomach to look for sources of bleeding.
• Colonoscopy. To rule out lower intestinal sources of bleeding, your doctor may recommend a procedure called colonoscopy. A thin, flexible tube equipped with a video camera is inserted into the rectum and guided to your colon. You're usually sedated during this test. A colonoscopy allows your doctor to view some or all of your colon and rectum to look for internal bleeding.

Your doctor may order these or other tests after a trial period of treatment with iron supplementation.

Mild iron deficiency anemia usually doesn't cause complications. However, left untreated, iron deficiency anemia can become severe and lead to health problems, including the following:

• Heart problems. Iron deficiency anemia may lead to a rapid or irregular heartbeat. Your heart must pump more blood to compensate for the lack of oxygen in the blood when you're anemic. In people with coronary artery disease — narrowing of the arteries that feed the heart — unchecked anemia can lead to angina. Angina is chest pain caused by decreased oxygen and blood flow to the heart muscle.
• Problems during pregnancy. In pregnant women, severe iron deficiency anemia has been linked to premature births and low birth weight babies. But the condition is easily preventable and treatable in pregnant women who receive iron supplements as part of their prenatal care.
• Growth problems. In infants and children, severe iron deficiency can lead to anemia as well as delayed growth. Untreated iron deficiency anemia can cause physical and mental delays in infants and children in areas such as walking and talking. Iron deficiency anemia also makes children more susceptible to lead poisoning and infections.

Once you become deficient in iron to the point you develop anemia, increased intake of iron-rich foods is beneficial but usually isn't enough to correct the problem. You need iron supplementation to build back your iron reserves, as well as to meet your body's daily iron requirements. In pregnant women, iron supplements help provide enough iron for both the mother and her fetus.

For children or adults with mild iron deficiency anemia, your doctor may recommend a daily multivitamin containing iron. But typically, doctors recommend iron tablets — such as prescription ferrous sulfate tablets or an over-the-counter supplement. These oral iron supplements are usually best absorbed in an empty stomach. However, because iron can irritate your stomach, you may need to take the supplements with food. Coated versions of iron tablets are easier on your stomach. But ask your doctor if they're right for you. Your doctor may recommend that you take iron supplements with orange juice or with a vitamin C tablet. Vitamin C in orange juice or tablet form helps increase iron absorption.

Iron supplements can cause constipation, so your doctor may recommend a stool softener or a laxative. Iron almost always turns stools black, which is a harmless side effect. Iron can be given by injection, but this usually isn't necessary.

A long-term process
Iron deficiency can't be corrected overnight. You may need to take iron supplements for several months or longer to replenish your iron reserves. Pregnant women routinely take prescription iron supplements for the duration of their pregnancy, to prevent or treat iron deficiency anemia.

Some infants may need supplemental iron. Breast milk and cow's milk may not contain enough iron for a growing infant. Most infant formulas contain adequate iron, but some babies require additional iron. Ask your baby's doctor about your child's iron requirements.

Treating causes other than poor diet
If iron supplements alone don't increase blood-iron levels in adults, it's likely the anemia is due to more than an iron-poor diet. It may be due to a source of bleeding or an iron-absorption problem that your doctor will need to investigate and treat. Depending on the cause, treatment may involve:

• Medications such as oral contraceptives to lighten heavy menstrual flow
• Antibiotics to treat ulcers
• Surgery to remove a bleeding polyp, a tumor or a fibroid

If iron deficiency anemia is severe, blood transfusions can help replace iron and hemoglobin quickly.

If you have a disease that causes anemia, such as leukemia, your iron levels may be normal. If that's the case, then iron supplementation isn't necessary and wouldn't be beneficial.

You can help prevent iron deficiency anemia by eating foods rich in iron, as part of a balanced diet. Eating plenty of iron-containing foods is particularly important for people who have higher iron requirements, such as children and menstruating or pregnant women.

Foods rich in iron include red meat, seafood, poultry and eggs. Meat sources of iron are called heme iron sources and are easily absorbed by the body. Plant-based foods also are good sources of iron, although they're less easily absorbed. Among the best are whole-grain or iron-fortified cereals, breads and pastas. Beans and peas, dark green leafy vegetables — such as spinach — and raisins, nuts, and seeds also contain iron.

You can enhance your body's absorption of iron by drinking citrus juice when you eat an iron-containing food. Vitamin C in citrus juices, like orange juice, helps your body better absorb dietary iron from animals and plants.