Iron Deficiency Anemia

Medically Reviewed by Carol DerSarkissian, MD on August 08, 2022
6 min read

Iron deficiency anemia is when your body doesn’t have enough red blood cells. 

Red blood cells carry oxygen from your lungs to the rest of your body. Every organ and tissue in your body needs oxygen to work. Without enough oxygen in your blood, you may feel tired, weak, and short of breath.

You get iron deficiency anemia when your body is low in iron. You need iron to make hemoglobin, a protein that helps your red blood cells carry oxygen. 

Your doctor will find out why your iron is low. Usually, you can treat iron deficiency anemia with supplements. Once your iron levels go up, you should start to feel better.

Mild iron deficiency anemia often isn't noticeable. When it gets more severe, you may have these symptoms:

Because these can also be symptoms of other conditions, see your doctor to get a diagnosis.

It can happen if you don't eat enough foods containing iron, your body can't properly absorb iron, you lose iron through your blood, or you’re pregnant.

Your diet is low in iron. How much iron you need depends on your age and gender. Men need at least 8 milligrams daily. Women ages 50 and younger need more -- 18 milligrams.

Your body can't absorb iron. Iron from the foods you eat is absorbed in your small intestine. Conditions like celiac disease,ulcerative colitis, or Crohn's disease can make it harder for your intestines to absorb iron. Surgery such as gastric bypass that removes part of your intestines, and medicines used to lower stomach acid can also affect your body's ability to absorb iron.

Blood loss. Some conditions can make you bleed inside your body, including:

Heavy periods. Women with heavy periods can become low in iron. 

Injuries. Any injury that causes you to lose blood can cause iron deficiency anemia.

Frequent blood donations.  You should wait at least 8 weeks between blood donations.

Pregnancy. When you’re expecting, you need extra iron to nourish your growing baby. If you don't get enough iron from your diet or supplements, you can become deficient.

End-stage kidney failure. If you are getting dialysis for end-stage kidney failure, you can lose blood. Some people with end-stage kidney failure also take medications that can cause iron-deficiency anemia.

Medications. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can cause internal gastrointestinal bleeding. Proton pump inhibitors, used to control acid reflux, can prevent your body from absorbing enough iron.

Chronic health conditions that cause inflammation. This can include congestive heart failure as well as obesity.

Different factors can raise your risk of getting iron deficiency anemia. Some can be changed and some cannot. Risk factors include:

Age. Children aged 6 months to 2 years, teens, and adults over the age of 65 are most at risk.

Lifestyle. This can include exercising a lot (including endurance sports) and not eating enough foods rich in iron.  

Lead. Lead from water or from environmental sources can get in the way of making red blood cells.

Family history and genetics. Two inherited diseases, hemophilia and von Willebrand disease, can cause you to bleed more and lose iron.

Gender. Girls and women who have heavy periods or are pregnant or breastfeeding need more iron.

Your doctor will do one or more of these blood tests to find out if you have iron deficiency anemia.

  • Complete blood count (CBC). This test checks to see how many red blood cells you have.
  • Peripheral blood smear. This test looks at the size and shape of your red blood cells. In iron deficiency anemia, red blood cells are smaller than usual.
  • Hematocrit. This test shows how much of your blood is made up of red cells.
  • Hemoglobin. This test shows the amount of this protein in your blood. If you have anemia, your hemoglobin will be low.
  • Serum iron. This test shows how much iron is in your blood.
  • Ferritin. This test shows how much iron is stored in your body by measuring this protein.
  • Transferrin and total iron-binding capacity (TIBC). These tests show how much of a protein called transferrin is free to carry iron through your body.
  • Reticulocyte count. This test shows how many reticulocytes (immature red blood cells) you have in your blood. If you have iron deficiency anemia, your reticulocyte count is usually low because you’re not making many new red blood cells.

If blood tests show you have iron deficiency anemia, you might need other tests like these to see what's causing it.

  • Endoscopy. Your doctor uses a tube with a camera on one end to look inside your esophagus or colon. Endoscopy can find bleeding in your GI tract from ulcers, polyps, or other growths.
  • Pelvic ultrasound or uterinebiopsy. If you bleed a lot during your monthly periods, this test can find the cause.
  • Fecal occult blood test. This test looks for tiny amounts of blood in your poop to check for cancer and other causes of bleeding in your intestines.

You can treat iron deficiency anemia by taking iron supplements. Most people take 150 to 200 milligrams each day, but your doctor will recommend a dose based on your iron levels. Taking vitamin C helps your body absorb the iron.

You might need to take iron supplements for a few months or more to get your levels to normal. If your intestines don't absorb iron well, you can take iron straight into your bloodstream through an intravenous tube (IV).

But be warned: Iron supplements can cause constipation, nausea, vomiting, diarrhea, heartburn, and dark-colored poop.

Your symptoms should start to go away after about a week. Your doctor will check your blood to see if your anemia has improved.

You can also get more iron in your diet by eating more of these foods:

  • Beef, pork, liver, chicken, turkey, duck, and shellfish
  • Leafy greens such as broccoli, kale, turnip greens, and collard greens
  • Peas, lima beans, black-eyed peas, and pinto beans
  • Iron-enriched cereals and other grains
  • Dried fruits, such as prunes and raisins

Eating foods high in iron may also prevent anemia.

If supplements don't help with your symptoms or your anemia is severe, you might need a transfusion of red blood cells. Or, if you have an ulcer, tumor, or other growth, it may need to be treated with medicines or surgery.

If you don’t know you have iron deficiency anemia or if you know you have it but aren’t getting the right treatment, you could end up with complications such as:

  • Depression.
  • A higher risk of infection. This is because your immune system may not be working properly.
  • Problems with pregnancy. This can include preterm delivery and low-birth-weight babies.
  • Heart problems. Without enough red blood cells, your heart has to pump harder to get enough nutrients to the rest of your body. This causes strain, which can lead to heart failure, irregular heartbeat, an enlarged heart, or a heart murmur.
  • Developmental delays in children. This can include cognitive problems and motor problems.