Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia. Iron deficiency anemia is a decrease in the number of red cells in the blood caused by too little iron.

See also: Iron-deficiency anemia - children

Iron deficiency anemia is the most common form of anemia. About 20% of women, 50% of pregnant women, and 3% of men do not have enough iron in their body.

Iron is a key part of hemoglobin, the oxygen-carrying protein in the blood. Your body normally gets iron through diet and by recycling iron from old red blood cells. Without iron, the blood cannot carry oxygen effectively. Oxygen is needed for every cell in the body to function normally.

The causes of iron deficiency are:

• Blood loss (including from heavy menstrual bleeding)
• Poor absorption of iron by the body
• Too little iron in the diet

It can also be related to lead poisoning in children.

Anemia develops slowly after the normal iron stores in the body and bone marrow have run out. In general, women have smaller stores of iron than men because they lose more through menstruation. They are at higher risk for anemia than men.

In men and postmenopausal women, anemia is usually caused by gastrointestinal blood loss from:

• Certain types of cancer (esophagus, stomach, colon)
• Long-term use of aspirin or nonsteroidal anti-inflammatory medications (NSAIDS)
• Peptic ulcer disease
• Ulcers

Iron deficiency anemia may also be caused by poor absorption of iron in the diet, due to:

• Celiac disease
• Crohn's disease
• Gastric bypass surgery
• Taking antacids

High-risk groups include:

• Infants, children, and adolescents who are growing quickly
• People who do not get enough iron in their diet
• People who use aspirin, ibuprofen or other arthritis medicines long-term
• Pregnant or breast-feeding women who need extra iron
• Seniors
• Women of child-bearing age who have lost blood through heavy menstrual periods

• Blue color to whites of the eyes
• Brittle nails
• Decreased appetite (especially in children)
• Fatigue
• Headache
• Irritability
• Pale skin color
• Shortness of breath
• Sore tongue
• Unusual food cravings (called pica)
• Weakness

Note: There may be no symptoms if the anemia is mild.

• Fecal occult blood test
• Hematocrit and hemoglobin (red blood cell measures)
• Iron binding capacity (TIBC) in the blood
• RBC indices
• Serum ferritin
• Serum iron level

The cause of the iron deficiency must be found, especially in older patients who face the greatest risk for gastrointestinal cancers.

Iron supplements (ferrous sulfate) are available. For the best iron absorption, take these supplements with an empty stomach. However, many people cannot tolerate this and may need to take the supplements with food.

Patients who cannot tolerate iron by mouth can take it through a vein (intravenous) or by an injection into the muscle.

Milk and antacids may interfere with the absorption of iron and should not be taken at the same time as iron supplements. Vitamin C can increase absorption and is essential in the production of hemoglobin.

Pregnant and breast-feeding women will need to take extra iron because their normal diet usually will not provide the required amount.

The hematocrit should return to normal after 2 months of iron therapy. However, iron should be continued for another 6 - 12 months to replenish the body's iron stores in the bone marrow.

Iron-rich foods include:

• Eggs (yolk)
• Fish
• Legumes (peas and beans)
• Meats (liver is the highest source)
• Poultry
• Raisins
• Whole-grain bread

With treatment, the outcome is likely to be good. Usually, blood counts will return to normal in 2 months.

There are usually no complications. However, iron deficiency anemia may come back. Get regular follow-ups with your health care provider.

Children with this disorder may be more likely to get infections.

Call for an appointment with your health care provider if:

• You have symptoms of this disorder
• You notice blood in your stool

Everyone's diet should include enough iron. Red meat, liver, and egg yolks are important sources of iron. Flour, bread, and some cereals are fortified with iron. If you aren't getting enough iron in your diet (uncommon in the U.S.), take iron supplements.

During periods when you need extra iron (such as pregnancy and breast-feeding), increase the amount of iron in your diet or take iron supplements.

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Alleyne M, Horne MK, Miller JL. Individualized treatment for iron-deficiency anemia in adults. Am J Med. 2008;121:943-948.

Killip S, Bennett JM, Chambers MD. Iron deficiency anemia. Am Fam Physician. Mar 1 2007;75(5):671-8.