Anemia is a condition in which the body does not have enough healthy red blood cells. Iron helps make red blood cells.A.D.A.M.

Causes, incidence, and risk factors

Iron deficiency anemia is the most common form of anemia.

Red blood cells bring oxygen to the body's tissues. Healthy red blood cells are made in your bone marrow. Red blood cells circulate through your body for 3 to 4 months. Parts of your body like your spleen remove old blood cells.

Iron is a key part of red blood cells. Without iron, the blood cannot carry oxygen effectively. Your body normally gets iron through your diet. It also reuses iron from old red blood cells.

You get iron deficiency anemia when your body's iron stores run low. This can occur because:

• You lose more blood cells and iron than your body can replace
• Your body does not do a good job of absorbing iron
• Your body is able to absorb iron, but you are not eating enough foods that contain iron.
• Your body needs more iron than normal (such as if you are pregnant or breastfeeding)

Bleeding can cause iron loss. Common causes of bleeding are:

• Heavy, long, or frequent menstrual periods
• Cancer in the esophagus, stomach, or colon
• Esophageal varices usually from cirrhosis
• The use of aspirin, ibuprofen, or arthritis medicines for a long time, which can cause gastrointestinal bleeding
• Peptic ulcer disease

The body may not absorb enough iron in your diet due to:

• Celiac disease
• Crohn's disease
• Gastric bypass surgery
• Taking too many antacids that contain calcium

You may not get enough iron in your diet if:

• You are a strict vegetarian
• You are an older adult and do not eat a full diet

Symptoms

You may have no symptoms if the anemia is mild.

Most of the time, symptoms are mild at first and develop slowly. Symptoms may include:

• Feeling grumpy
• Feeling weak or tired more often than usual, or with exercise
• Headaches
• Problems concentrating or thinking

As the anemia gets worse, symptoms may include:

• Blue color to the whites of the eyes
• Brittle nails
• Light-headedness when you stand up
• Pale skin color
• Shortness of breath
• Sore tongue

Symptoms of the conditions that cause iron deficiency anemia include:

• Dark, tar-colored stools or blood
• Heavy menstrual bleeding (women)
• Pain in the upper belly (from ulcers)
• Weight loss (in people with cancer)

Signs and tests

To diagnose anemia, your doctor may order these blood tests:

• Hematocrit and hemoglobin (red blood cell measures)
• RBC indices

Tests to check iron levels in your blood include:

• Bone marrow exam (rare)
• Iron binding capacity (TIBC) in the blood
• Serum ferritin
• Serum iron level

Tests that may be done to look for the cause of iron deficiency:

• Colonoscopy
• Fecal occult blood test
• Upper endoscopy

Treatment

Before treatment, you and your health care provider must first search for the cause of your anemia. Next, the reason for iron deficiency needs to be discovered.

Treatment may include taking iron supplements and eating iron-rich foods.

Iron supplements (most often ferrous sulfate) are needed to build up the iron stores in your body. Most of the time, your doctor or nurse will measure your iron levels before starting supplements.

If you cannot take iron by mouth, you may need to take it through a vein (intravenous) or by an injection into the muscle.

Pregnant and breastfeeding women will need to take extra iron because they often cannot get enough iron from their normal diets.

Your hematocrit should return to normal after 2 months of iron therapy. You will need to keep taking iron for another 6 - 12 months to replace the body's iron stores in the bone marrow.

Iron-rich foods include:

• Chicken and turkey
• Dried lentils, peas, and beans
• Fish
• Meats (liver is the highest source)
• Peanut butter
• Soybeans
• Whole-grain bread

Other sources include:

• Oatmeal
• Raisins, prunes, and apricots
• Spinach, kale, and other greens

Expectations (prognosis)

With treatment, the outcome is likely to be good. However, it does depend on the cause.

Calling your health care provider

Call your health care provider if:

• You have symptoms of iron deficiency
• You notice blood in your stool

Prevention

A well rounded diet should include enough iron. Red meat, liver, and egg yolks are high sources of iron. Flour, bread, and some cereals are fortified with iron. Take iron supplements if you aren't getting enough iron in your diet (uncommon in the United States).

References

1. Brittenham GM. Disorders of Iron Homeostasis: Iron Deficiency and Overload. Ln: Hoffman R, Benz EJ Jr. Silberstein LE, Heslop HE, Weitz JI, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, Pa: Saunders Elsevier; 2012:chap 4.
2. Mabry-Hernandez IR. Screening for iron deficiency anemia--including iron supplementation for children and pregnant women. Am Fam Physician. 2009 May 15;79(10):897-8. [PubMed: 19496390]
3. Alleyne M, Horne MK, Miller JL. Individualized treatment for iron-deficiency anemia in adults. Am J Med. 2008;121:943-948.. [PMC free article: PMC2582401] [PubMed: 18954837]

Review Date: 3/3/2013.

Reviewed by: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.