Anemia

Anemia is caused by a lack of red blood cells or hemoglobin, the oxygen-carrying protein found in red blood cells. Anemia is most often due to a deficiency in iron, a key component of hemoglobin. (That’s why it is often treated with iron supplements). Anemia can be triggered by blood loss, a folic acid or vitamin B12 deficiency, sickle cell disease, and a genetic disorder called thalassemia, among other causes. In the U.S., 2% to 5% of women and 1% of men have iron deficiency anemia. 

Tips for preventing anemia

 Anemia occurs when there are too few red blood cells in the blood. A complete blood count (CBC) can determine whether anemia is present.

Women who have heavy and prolonged periods may develop anemia, because the body cannot produce blood as fast as it is being lost. Your body needs iron to make new blood cells. The recommended dietary allowance (RDA) is 18 mg. You may need to increase your iron intake to 20 mg a day if your periods are heavy or prolonged.

Your diet is the best source of iron. It is better for you to eat a balanced diet than it is to take dietary supplements. Red meats, shellfish, eggs, beans, and green leafy vegetables are the best sources of iron.

Other good sources of iron include:

• Clams [canned drained, 3 oz (85.1 g)]
• Oysters [3.5 oz (99.2 g)]
• Shrimp [3.5 oz (99.2 g)]
• Beef liver [3 oz (85.1 g)]
• Lean beef [3 oz (85.1 g)]
• Lentils (uncooked, 1 cup)
• Green peas (uncooked, 1 cup)
• Spinach (uncooked, 1 cup)
• Raisins (1 cup)
• Prunes (10)
• Enriched wheat bread (1 slice)
• Egg (1)
• Iron-enriched cereals (1 cup, read label for exact amounts)

Cooking in iron cookware will add small amounts of iron to the food.

Vitamin C improves the absorption of iron. Be sure your diet includes 250 mg of vitamin C a day.

Consider using a nonprescription iron supplement (such as ferrous sulfate) or a multivitamin if you are unable to meet your need for iron through your diet. For more information about iron, see the topic Healthy Eating.

You may become constipated when you are taking an iron supplement. To avoid constipation:

• Increase dietary fiber.
• Eat plenty of fruits.
• Drink at least 2 to 4 extra glasses of water a day.

Iron Deficiency Anemia 

What is iron deficiency anemia?

Iron deficiency anemia occurs when your body doesn't have enough iron.

Iron is important because it helps you get enough oxygen throughout your body. Your body uses iron to make hemoglobin. Hemoglobin is a part of your red blood cells. Hemoglobin carries oxygen through your body. If you do not have enough iron, your body makes fewer and smaller red blood cells . Then your body has less hemoglobin, and you cannot get enough oxygen.

What causes iron deficiency anemia?

Iron deficiency anemia is caused by low levels of iron in the body. You might have low iron levels because you:

• Have heavy menstrual bleeding.
• Are not getting enough iron in food. This can happen in people who need a lot of iron, such as small children, teens, and pregnant women.
• Have bleeding inside your body. This bleeding may be caused by problems such as ulcers, hemorrhoids, or cancer. This bleeding can also happen with regular aspirin use. Bleeding inside the body is the most common cause of iron deficiency anemia in men and in women after menopause.
• Cannot absorb iron well in your body. This problem may occur if you have celiac disease or if you have had part of your stomach or small intestine removed.

What are the symptoms?

You may not notice the symptoms of anemia, because it develops slowly and the symptoms may be mild. In fact, you may not notice them until your anemia gets worse. As anemia gets worse, you may:

• Feel weak and tire out more easily.
• Feel dizzy.
• Be grumpy or cranky.
• Have headaches.
• Look very pale.
• Feel short of breath.
• Have trouble concentrating.

Babies and small children who have anemia may:

• Be fussy.
• Have a short attention span.
• Grow more slowly than normal.
• Develop skills, such as walking and talking, later than normal.

Anemia in children must be treated so that mental and behavior problems do not last long.

How is iron deficiency anemia diagnosed?

If you think you have anemia, see your doctor. Your doctor will do a physical exam and ask you questions about your medical history and your symptoms. Your doctor will take some of your blood to run tests. These tests may include a complete blood count to look at your red blood cells and an iron test that shows how much iron is in your blood.

Your doctor may also do tests to find out what is causing your anemia.

How is it treated?

Your doctor will probably have you take iron supplement pills to treat your anemia. Most people begin to feel better after a few days of taking iron pills. But do not stop taking the pills even if you feel better. You will need to keep taking the pills for several months to build up the iron in your body.

If your doctor finds an exact cause of your anemia, such as a bleeding ulcer, your doctor will also treat that problem.

If you think you have anemia, do not try to treat yourself. Do not take iron pills on your own without seeing your doctor first. If you take iron pills without talking with your doctor first, the pills may cause you to have too much iron in your blood, or even iron poisoning. Your low iron level may be caused by a serious problem, such as a bleeding ulcer or colon cancer. These other problems need different treatment than iron pills.

You can get the most benefit from iron pills if you take them with vitamin C or drink orange juice. Do not take your iron pills with milk, caffeine, foods with high fiber, or antacids.

Can you prevent iron deficiency anemia?

You can prevent anemia by eating the right amount of iron every day. Iron-rich foods include meats, eggs, and whole-grain or iron-fortified foods. You can also get iron from many other foods, including peas, beans, oatmeal, prunes, and figs.

You can prevent anemia in babies and children by feeding them enough iron. To make sure they get enough iron:¹

• Breast-feed your baby for at least a year or as long after as you and your child desire. Introduce iron-enriched solid foods at 6 months of age to complement the breast milk. Iron-fortified cereals are a good source of iron.
• After 6 months of age, give your child 2 to 3 servings of iron-rich foods a day.
• For babies who were weaned from the breast or the bottle before 12 months of age, give iron-fortified formula, not cow's milk or goat's milk. Cow and goat milks are low in iron.

If you are pregnant, you can prevent anemia by taking prenatal vitamins. Your doctor will give you prenatal vitamins that include iron. Your doctor will also test your blood to see if you are anemic. If you are anemic, you will take a higher-dose iron pill.

Blood transfusions for sickle cell disease

During a blood transfusion, a person (the recipient) receives healthy blood from another person (the donor). The donated blood is carefully screened for diseases before it is used. Before receiving a blood transfusion, the recipient's blood is analyzed closely (using blood type) to make sure the donor blood is a close match to the recipient's.

Blood is transfused into an arm vein slowly over 1 to 4 hours (except in an emergency when blood is transfused more quickly).

Blood transfusions can:

• Treat a sudden or short-term condition related to sickle cell disease.
• Treat severe complications of sickle cell disease.
• Prevent complications of sickle cell disease.
• Lower the risk of stroke in infants and children.

Blood transfusions aren't usually used to treat uncomplicated painful events or mild to moderate anemia.

What To Expect After Treatment

Following a blood transfusion, doctors keep a close watch on the person for any negative reactions.

• A transfusion reaction, resulting from mismatched blood type, may occur immediately or days later (5 to 20 days after transfusion). An acute transfusion reaction ranges from mild (fever, chills, and rash) to severe (shock, severe anemia, painful event, and death).
• A person receiving repeat blood transfusions may develop antibodies to the donor blood (called alloimmunization). Alloimmunization makes repeated transfusions more difficult. It occurs in about 1 out of 4 people with sickle cell disease who get frequent transfusions.¹

Hospital staff will also check for iron buildup in the body (iron overload). This can develop when a person gets many transfusions.

Why It Is Done

A blood transfusion lowers the amount of hemoglobin S red blood cells in the body. When there are fewer sickled hemoglobin S cells in the bloodstream, they are less likely to build up and block blood vessels.

Blood transfusion also increases the number of normal red blood cells in the body, increasing the supply of oxygen to the body.

Anemia

Some sudden complications of sickle cell disease cause the body's red blood cell count to drop to life-threatening levels (severe anemia). When severe, these conditions (including splenic sequestration, acute chest syndrome, and aplastic crisis) can be fatal if not treated with blood transfusions.

Chronic severe anemia from kidney failure may need treatment with periodic blood transfusions.

Surgery

After having general anesthesia and surgery, people with sickle cell disease are at risk for sickling-related problems and acute chest syndrome. Blood transfusions before surgery can prevent or treat these complications.

Red blood cell sickling-related complications (vaso-occlusion)

Blood transfusions can treat acute chest syndrome and leg ulcers.

Frequent blood transfusions may help prevent strokes in children who already had a stroke or are at high risk for a first stroke.²

How Well It Works

Blood transfusion is currently the single most effective and proven treatment for some severe complications of sickle cell disease.³

Blood transfusions reduce the risk of some complications of sickle cell disease and improve symptoms of severe anemia. Using repeat blood transfusions for 3 to 5 years can reduce the number of repeat strokes in children who have had a stroke.

Risks

A person receiving many blood transfusions will gradually collect too much iron in the body (iron overload). Very high levels of iron can lead to hemochromatosis, which can be fatal if untreated.

After 10 to 20 blood transfusions, iron chelation treatment can help rid the body of excess iron.

Donated blood is carefully screened for diseases before it is used. But it's remotely possible that donor blood may be contaminated with an infectious disease (such as HIV or hepatitis).

What To Think About

If you have repeated blood transfusions, you'll have routine testing for iron buildup in your body.

Though blood transfusions are an effective treatment for sickle cell disease complications, they are only used selectively. The risks of hemochromatosis and alloimmunization from repeat transfusions makes this procedure more suitable for severe and high-risk conditions.

Doctors and researchers continue to weigh the benefits against the risks of preventive blood transfusions. Repeat blood transfusion treatment for 3 to 5 years can reduce the number of repeat strokes in children who have sickle cell disease. It helps prevent a second stroke in most children. But some children who get repeat transfusions will still have a second stroke.

Complete the special treatment information form (PDF) (What is a PDF document?) to help you understand this treatment.

References

Citations

1. Steinberg MH (2008). Sickle cell disease and associated hemoglobinopathies. In L Goldman, D Ausiello, eds., Cecil Medicine, 23rd ed., pp. 1217–1226. Philadelphia: Saunders Elsevier.
2. Benz EJ (2008). Disorders of hemoglobin. In AS Fauci et al., eds., Harrison's Principles of Internal Medicine, 17th ed., pp. 635–643. New York: McGraw-Hill Medical.
3. Wang WC (2004). Sickle cell anemia and other sickling syndromes. In JP Greer et al., eds., Wintrobe's Clinical Hematology, 11th ed., pp. 1264–1311. Philadelphia: Lippincott Williams and Wilkins.