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 occurs when your body does not have enough iron. Iron helps make red blood cells. Iron deficiency anemia is the most common form of anemia.
Anemia - iron deficiency
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, such as 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.
Iron deficiency anemia develops when your body's iron stores run low. This can occur because:
Bleeding can cause iron loss. Common causes of bleeding are:
The body may not absorb enough iron in your diet due to:
You may not get enough iron in your diet if:
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:
As the anemia gets worse, symptoms may include:
Symptoms of the conditions (associated with bleeding) that cause iron deficiency anemia include:
To diagnose anemia, your health care provider may order these blood tests:
To check iron levels, your provider may order:
To check for causes (blood loss) of iron deficiency, your provider may order:
Iron supplements (most often ferrous sulfate) build up the iron stores in your body. Most of the time, your provider will measure your iron level before you start 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 diet.
Often your hematocrit should return to normal within 6 weeks of iron therapy. You will need to keep taking iron for another 6 to 12 months to replace the body's iron stores in the bone marrow.
Iron supplements are mostly well tolerated, but may cause:
Iron-rich foods include:
Other sources include:
Vitamin C helps your body to absorb iron. Good sources of vitamin C are:
With treatment, the outcome is likely to be good, but it does depend on the cause.
Call your provider if:
A balanced 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. If advised by your provider, take iron supplements if you are not getting enough iron in your diet.
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Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 33.
Means RT. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 149.
US Department of Health and Human Services; National Heart, Lung, and Blood Institute website. Iron-deficiency anemia. www.nhlbi.nih.gov/health-topics/iron-deficiency-anemia. Updated March 24, 2022. Accessed June 8, 2022.
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.