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What is Iron Deficiency?

Iron deficiency means you have less iron than your body needs to be healthy. You need iron to make hemoglobin, the part of red blood cells that carries oxygen through your body. Iron deficiency is the most common cause of anemia, a condition in which your blood doesn’t have enough red blood cells. If you don’t have enough red blood cells, your body doesn’t get enough oxygen.

Iron-deficiency anemia may cause you to look pale and feel tired, or you may not have any symptoms at first. But if your anemia goes untreated, it can cause serious complications. When you don’t have enough red blood cells, your heart has to work harder to get enough oxygen to your organs. Your heart has to work harder even before you notice any symptoms. This extra work can make the wall of your heart muscle thicken, a condition called LVH (left ventricular hypertophy). LVH is serious, and can require hospitalization and sometimes cause death. Treating your anemia right away is essential.

When to See a Doctor

Check with your doctor if you:

  • Experience the symptoms of anemia, or think for any reason that you may have anemia
  • Notice blood in your stool


Many people, including about 20 percent of women, don’t have enough iron. There are a number of reasons you could develop iron-deficiency anemia. These include:

  • Blood loss, especially in women who lose a lot of blood during heavy menstrual periods
  • Not enough iron in your diet
  • Not able to absorb enough iron from foods, especially if you have digestive tract diseases, ongoing blood loss from another health condition, or have had gastric bypass surgery
  • Increased need for iron, especially in children who are growing rapidly or pregnant women who need iron for their baby
  • Diagnosis and Tests

    If you or your doctor thinks you may have anemia, you’ll have a blood test called a complete blood count (CBC). This shows how much hemoglobin you have. Hemoglobin is the substance in red blood cells that carries oxygen through your body.

    If the CBC test shows that you have anemia, your doctor will do other blood tests to determine what’s causing your anemia, how severe it is, and what the best treatment is. If your doctor thinks you may have bleeding inside your body, the doctor may do a colonoscopy or imaging scans to find out where you are bleeding.


    If iron deficiency is the cause of your anemia, you may be treated in the following ways:

    • Iron supplements. Be sure to take your iron supplements exactly as directed.
      • Iron supplements are absorbed best if taken one hour before meals. Taking them before you eat, though, may give you an upset stomach or constipation. Talk with your doctor about the best way to handle side effects.
      • Some people have digestive problems when they take iron. If you can’t tolerate iron supplements taken by mouth, you may be given iron intravenously or as an injection in to a muscle.
      • Do not drink milk or take antacids at the same time as your iron supplements. They may interfere with absorbing the iron.
      • It usually takes about 2 to 3 weeks of regular iron supplements before your symptoms start to improve.
      • You may need to keep taking iron for several months to build up your reserves of iron and prevent your anemia from returning. Take your pills for as long as your doctor recommends, even if your symptoms have improved.
    • Diet and nutrition. Eating more iron-rich foods is a good, natural way to improve your health. Even if you eat more iron, though, most people with anemia still need to take iron supplements.
      • Iron rich foods include red meat (especially liver), egg yolks, fish, peas and beans, chicken, and whole-grain bread.
      • Vitamin C may increase the absorption of iron, and also helps your body produce hemoglobin. Ask your doctor if you should be taking it.

    With treatment, most people recover from iron-deficiency anemia in 2 to 3 months. You may need to take iron supplements for several months longer, though, to build up your reserves of iron.


    You can prevent iron-deficiency anemia by getting enough iron. During times when your body needs more iron, such as pregnancy, increase the amount of iron in your diet or ask your doctor if you should take iron supplements.

    If you have had iron-deficiency anemia and want to prevent it from happening again, take your iron supplements exactly as the doctor recommended, even if you’re feeling better.

    Support and Resources

    NIH National Heart, Lung, and Blood Institute, “What Is Iron-Deficiency Anemia?”


    Anemia begins gradually, and at first you may not have any symptoms. As your anemia worsens, your anemia may cause you to:

    • Have low energy and feel tired, weak, dizzy, irritable, depressed, or have trouble concentrating
    • Have physical symptoms such as pale skin, brittle nails, shortness of breath, chest pain, cold hands or feet, or an irregular heartbeat
    • Want to eat unusual things such as ice, paper, dirt, clay, or pure starch