What Is Anemia?
Anemia is the most common blood disorder. According to the National Heart, Lung, and Blood Institute, anemia affects more than 3 million Americans.
Red blood cells carry hemoglobin, an iron-rich protein that attaches to oxygen in the lungs and carries it to tissues throughout the body. Anemia occurs when you do not have enough red blood cells or when your red blood cells do not function properly.
When you have anemia, your body lacks oxygen, so you may feel tired or weak. Other symptoms might include:
- Shortness of breath
- Dizziness
- Fast or irregular heartbeat
- Pounding or “whooshing” in your ears
- Headache
- Cold hands or feet
- Pale or yellow skin
- Chest pain
Many people are at risk for anemia because of poor diet, intestinal disorders, chronic diseases, infections, and other conditions. Women who are menstruating or pregnant and people with chronic medical conditions are most at risk for this disease. The risk of anemia increases as people grow older. People who engage in vigorous athletic activities, such as jogging or basketball, may develop anemia as a result of red blood cells breaking down in the bloodstream.
Many forms of anemia can be easily treated by eating foods rich in iron (such as dark green leafy vegetables, red meat, fortified cereals, eggs, and peanuts) and/or taking dietary supplements. Other types can be treated by addressing the underlying cause.
Some common types of anemia are:
Iron-deficiency anemia is the most common type of anemia. It happens when you do not have enough iron in your body. Iron deficiency is usually due to blood loss but may occasionally be due to poor absorption of iron. Pregnancy and childbirth consume a great deal of iron and thus can result in this form of anemia. People who have had gastric bypass surgery for weight loss or other reasons may also be iron deficient due to poor absorption.
The Role of Red Blood Cells in Anemia
Six-year-old Ezra Crosby was born with hereditary spherocytosis, a serious type of anemia. Previously not able to keep up with other kids his age, Ezra now has more energy thanks to treatment he received for his anemia - surgical removal of most of his spleen.
Vitamin-deficiency anemia may result from low levels of vitamin B12 or folate (folic acid), usually due to poor dietary intake. Pernicious anemia is a condition in which vitamin B12 cannot be absorbed in the gastrointestinal tract.
Aplastic anemia is a rare form of anemia that occurs when the body stops making enough red blood cells. Common causes include viral infections, exposure to toxic chemicals, drugs, and autoimmune diseases.
Hemolytic anemia occurs when red blood cells are destroyed in the bloodstream or in the spleen. Hemolytic anemia may be due to mechanical factors (leaky heart valves or aneurysms), infections, autoimmune disorders, or inherited abnormalities in the red blood cell. Inherited abnormalities may affect the hemoglobin or the red blood cell structure or function. Examples of inherited hemolytic anemias include some types of thalassemia and low levels of enzymes such as pyruvate kinase. The treatment will depend on the cause.
Sickle cell anemia is an inherited hemolytic anemia in which the hemoglobin protein is abnormal, causing the red blood cells to be rigid and unable to flow through small blood vessels.
Anemia caused by other diseases—Some diseases can affect the body’s ability to make red blood cells. For example, some patients with kidney disease develop anemia because the kidneys are not making enough hormones to signal the body to make red blood cells. Chemotherapy used to treat various cancers often impairs the body’s ability to make new red blood cells, and anemia often results from this treatment.
Where Can I Find More Information?
If after further exploration of the Blood: The Vital Connection Web site you find that you are interested in learning more about blood diseases and disorders, here are a few other resources that may be of some help:
The American Society of Hematology (ASH) Education Book, updated yearly by experts in the field, is a collection of articles about the current treatment options available to patients. The articles are categorized here by disease type. If you are interested in learning more about a particular blood disease, we encourage you to share and discuss these articles with your doctor.
Search Blood, the official journal of ASH, for the results of the latest blood research. While recent articles generally require a subscriber login, patients interested in viewing an access-controlled article in Blood may obtain a copy by e-mailing a request to the Blood Publishing Office.
This section includes a list of Web links to patient groups and other organizations that provide information.