Iron Deficiency Anemia

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is iron deficiency anemia?

Iron deficiency anemia is a reduction in the number of healthy red blood cells produced due to an insufficient supply of iron in the body. It is the most common cause of anemia in the United States. Red blood cells carry oxygen from the lungs to the rest of the body. A reduction in red blood cells limits the amount of oxygen reaching your limbs and organs and may cause various symptoms, including fatigue, dizziness, and pallor (pale skin).

Low levels of iron may be caused by blood loss, by the body’s inability to absorb sufficient iron from the digestive tract, or by low levels of iron in your diet. Pregnancy is also a cause of iron deficiency anemia in women due to the iron requirements of the growing fetus.

Iron deficiency anemia is the most common type of anemia in the United States. Approximately 8% of women (17 to 30% of pregnant women) and 4% of men do not have enough iron in their body and are at risk of developing iron deficiency anemia. Globally, about 43% of children younger than 5 years and 38% of pregnant women have iron deficiency anemia.

Iron deficiency anemia is usually treated successfully with dietary changes and iron supplements. In severe cases, blood transfusions may be necessary. In many cases, iron deficiency anemia can be prevented by adequate dietary intake of iron or the use of iron supplements in people who are at risk.

Symptoms of iron deficiency anemia are often mild. Rarely, severe iron deficiency anemia may cause serious symptoms. Seek immediate medical care (call 911) if you develop serious symptoms such as difficulty breathing or chest pains. Seek prompt medical care if you are being treated for iron deficiency anemia but have persistent or recurrent mild symptoms.

What are the symptoms of iron deficiency anemia?

If you have a mild case of iron deficiency anemia, you may not experience any symptoms. However, many common symptoms are associated with moderate to severe iron deficiency anemia and can vary in intensity among individuals.

Common symptoms of iron deficiency anemia

You may experience symptoms of iron deficiency anemia daily or occasionally. At times, any of these symptoms can be severe:

  • Brittle nails

  • Cheilitis (also called perleche, sores at the corners of the mouth)

  • Cravings for things that are not food, such as ice, dirt, paint or starch

  • Dizziness

  • Fatigue

  • Frequent infections

  • Heart palpitations

  • Pale skin, gums, or nail beds

  • Restless legs

  • Swelling or soreness of tongue (glossitis)

  • Weakness

Symptoms that might indicate a serious condition

In some cases, iron deficiency anemia can be a serious condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms including:

What are the stages of iron deficiency anemia?

In most cases of iron deficiency anemia, the condition develops with time as the body depletes iron stored inside cells. There are five stages to iron deficiency and anemia, with only the final stage causing absolute anemia and symptoms:

  • Stage 1 is depletion of iron from bone marrow, where red blood cells develop.

  • Stage 2 is depletion of red blood cells and falling iron levels in the blood (serum iron).

  • Stage 3 is anemia, but red blood cells may appear normal under a microscope.

  • Stage 4 is anemia with red blood cells that appear smaller and paler than normal.

  • Stage 5 is anemia with symptoms, such as fatigue, paleness, weakness, heart palpitations, and brittle nails. 

Identifying the stage of iron deficiency anemia is part of the diagnostic process and helps determine the most appropriate treatment.

What causes iron deficiency anemia?

Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to other body tissues. Hemoglobin is made primarily of iron. When your iron levels are low, your body makes fewer red blood cells or makes red blood cells with less hemoglobin, and these cells cannot carry as much oxygen.

Low iron levels may result from a diet lacking in iron, an inability to absorb enough iron, or blood loss. In addition, pregnancy can result in iron deficiency anemia due to the iron needs of the growing fetus.

Causes of iron deficiency anemia due to poor absorption of iron

Some people who eat iron-rich diets may still develop iron deficiency anemia if their body cannot absorb iron. An inability to absorb iron from the digestive tract may be due to:

Causes of iron deficiency anemia due to blood loss

Causes of blood loss include:

  • Childbirth

  • Frequent blood donor

  • Internal bleeding (cancer, coagulation defect, platelet abnormality)

  • Menstruation

  • Severe injuries

  • Surgery

What are the risk factors for iron deficiency anemia?

Several factors increase the risk of developing iron deficiency anemia. Not all people with risk factors will get iron deficiency anemia. Risk factors for developing iron deficiency anemia include the following circumstances:

  • Advanced age
  • Autoimmune disease
  • Breastfeeding
  • Cancer (or its treatment)
  • Endurance athletes, especially long-distance runners
  • Exposure to hookworm or other parasitic infestations
  • Extended use of aspirin or nonsteroidal anti-inflammatory medications, which can cause bleeding
  • Infancy or young childhood
  • Internal bleeding
  • Kidney or liver disease
  • Pregnancy
  • Use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin) 
  • Vegan or vegetarian diet
  • Women of childbearing age

Reducing your risk of iron deficiency anemia

You may be able to lower your risk of iron deficiency anemia by:

  • Eating a balanced diet containing iron-rich foods
  • Taking an iron supplement if recommended by your healthcare provider

What are some conditions related to iron deficiency anemia?

Anemia is a reduced amount of functional red blood cells. Iron deficiency anemia is the most common type of anemia in the United States. Other types of anemias include:

  • Anemia of chronic disease, linked to inflammatory factors causing premature breakdown or reduced production (erythropoiesis) of red blood cells (or both)
  • Aplastic anemia, caused by reduced production of young red blood cells (reticulocytes) in the bone marrow
  • Hemolytic anemia, caused by immune system attack and destruction (lysis) of red blood cells
  • Pernicious anemia, caused by vitamin B12 deficiency
     
  • Sickle cell anemia, caused by an inherited gene mutation in hemoglobin

How do doctors diagnose iron deficiency anemia?

Healthcare providers diagnose iron deficiency anemia by a person’s physical symptoms and blood test results. However, iron deficiency anemia screening is not an essential part of a routine physical unless the patient exhibits signs and symptoms of it, such as pale skin, dizziness, and fatigue. Mild anemia does not typically cause symptoms. Most providers order a standard blood count, which would identify an abnormal red blood cell count, but you may have to ask for an iron test.

If you do not have symptoms of iron deficiency anemia, your doctor may test you for iron deficiency anemia if you have known risk factors, such as celiac disease, Crohn’s disease, cancer (and its treatment), or history of gastric bypass surgery.

Providers typically screen pregnant women for iron deficiency anemia because pregnancy increases the risk of iron deficiency and it is dangerous for both the mother and baby. Some organizations recommend screening for iron deficiency anemia at 12 months of age. Others only recommend it for children with symptoms.

Iron deficiency anemia tests

These blood tests are necessary to diagnose iron deficiency anemia:

  • Complete blood count (CBC). This test evaluates several characteristics of blood, including the red blood cell (RBC) count, hemoglobin level, and percentage of RBCs in the blood. With anemia, RBCs will make up a lower percentage of blood volume compared to normal. A lower hemoglobin level is also a sign of iron deficiency.

  • Ferritin and iron. Ferritin is a protein that contains and stores excess iron inside cells. The test measures the amount of ferritin in the blood. Someone with low iron levels will have a lower than normal level of both iron and ferritin. 

  • Peripheral smear. This test examines red blood cells under a microscope. RBCs will be paler and smaller than normal with iron deficiency anemia. 

  • Reticulocyte count: These are young red blood cells. A lower number is a sign of iron deficiency anemia.  

Depending on your symptoms and blood test results, your doctor may order tests to evaluate organ function, including heart, liver and kidney tests.

Tests to determine the cause of iron deficiency anemia

Diagnostic tests to determine the underlying cause of iron deficiency anemia include:

  • Blood tests to check for bleeding disorders

  • Imaging exams, such as ultrasound and endoscopy, to determine the source of bleeding or to diagnose Crohn’s or celiac disease

  • Pregnancy test for females of childbearing age

  • Stool and urine tests to check for the presence of blood

  • Tests for infection

  • Tests for nutritional deficiency

Questions your provider may ask

To help diagnose your condition, your healthcare provider may ask you questions related to your symptoms including:

  • How long have you been experiencing symptoms?

  • What medications do you take?

  • Do you ever take aspirin or nonsteroidal anti-inflammatory drugs like ibuprofen (Advil, Motrin)?

  • Have you had a recent injury or surgery?

  • Have you ever been diagnosed with a gastrointestinal disorder?

  • When was your last colonoscopy (for patients 45 and older)?

  • Is there any possibility you could be pregnant?

  • Are you a vegetarian? Describe your diet over the past several months.

How is iron deficiency anemia treated?

Treatment depends on the severity and underlying cause of anemia. The overall goal of iron deficiency anemia treatment is to restore iron levels to normal. Iron levels may be restored through dietary changes, supplements, or, in severe cases, blood transfusions. Your healthcare provider may prescribe iron or vitamin C supplements. Vitamin C helps your body absorb iron. You can take these supplements by mouth.

Iron deficiency and anemia are such a threat to the health and well-being of the mother and developing fetus that maternity and prenatal care providers recommend iron-containing prenatal vitamins to pregnant women universally.

Iron deficiency anemia caused by chronic disease, such as inflammatory bowel disease, is anemia of chronic disease. Treatment is more complicated. Increasing dietary iron or taking iron supplements will not treat anemia of chronic disease; rather, treating the underlying disease will improve the absorption of iron from any source. Getting an accurate diagnosis of the underlying cause of iron deficiency anemia will help prevent complications of anemia or its treatment.

For cases of severe iron deficiency anemia, your healthcare provider may determine that more immediate treatment is needed to restore iron and red blood cells levels. Iron may be injected through an IV or into your muscles. Additionally, the amount of red blood cells may be increased through a blood transfusion.

Dietary changes to treat iron deficiency anemia

Your healthcare provider may recommend that you incorporate iron-rich foods into your diet. The best source of dietary iron is red meat. Poultry, pork, fish and shellfish are also good sources of iron. Common non-meat foods high in iron include:

  • Dried raisins, apricots or peaches
  • Eggs
  • Iron-fortified cereal, bread and pasta
  • Peanuts, peanut butter, almonds
  • Peas, lentils and beans
  • Prune juice
  • Spinach or other dark green, leafy vegetables

Treatment of bleeding as the cause of iron deficiency anemia

If bleeding is identified as the cause of iron deficiency anemia, treatment will aim to correct the bleeding. Following are some of the causes of bleeding and their treatment:

  • Heavy menstrual flow may be reduced by oral contraceptive use.
  • Intestinal polyps or tumors may be removed surgically.
  • Ulcers may be treated with antibiotics or other medications.

What are the diet and nutrition tips for iron deficiency anemia?

For mild iron deficiency anemia, increasing the amount of iron in your body by eating iron-rich foods will likely reverse the course. Meat, fish and poultry are a great source of heme iron, the type of dietary iron most easily absorbed by the body (about 30% of the iron from meat is absorbed). Iron-rich, but non-meat foods have non-heme iron. The body absorbs 2 to 10% of non-heme iron.

Common sources of iron include:

  • Dark, leafy greens like spinach, kale and broccoli

  • Dried fruit

  • Eggs

  • Iron-fortified foods

  • Legumes like lentils, green peas, and many kinds of beans

  • Peanuts

  • Red meat, poultry and fish

  • Sweet potatoes

  • Tofu

Boosting your vitamin C intake can increase the amount of non-heme iron your body absorbs from non-meat sources. Tomatoes, oranges, grapefruit, and sweet peppers are good sources of vitamin C.

If you have moderate to severe iron deficiency anemia, an iron-rich diet is still important but not enough to treat the condition. Iron supplementation and blood transfusion may be necessary to increase iron levels and oxygen-carrying red blood cells to a healthy level.

How does iron deficiency anemia affect quality of life?

Iron is an essential mineral and micronutrient. The only natural way to get iron is through your diet. A lack of iron leading to anemia can have long-term consequences, including maternal death, low birth weight, and delayed growth and learning difficulties in children. Iron deficiency anemia can cause organ damage, including heart and brain damage. These conditions, in turn, reduce quality of life. Iron deficiency anemia can also worsen existing conditions. Unfortunately, iron deficiency and anemia often progress without a diagnosis.

Once you begin treatment for iron deficiency anemia, it can take several months to a year for the body to recover normal levels of iron and healthy blood. It is important to keep your follow-up appointments with your doctor, to check iron levels and red blood cell counts. If you take iron supplements, you also need to know if you have reached an excess iron level in your blood, which can cause complications. Only take iron supplements under guidance from a licensed healthcare professional.

What are the potential complications of iron deficiency anemia?

The outlook for iron deficiency anemia is good if you receive appropriate treatment. Left untreated, the complications of iron deficiency anemia can be serious. You can help minimize your risk of serious complications by following the treatment plan you and your healthcare professional design specifically for you. Complications of iron deficiency anemia include:

  • Adverse effects from blood transfusion

  • Adverse effects from iron supplementation therapy

  • Frequent infections

  • Growth problems in children

  • Heart problems, such as irregularities of heartbeat or rhythm

  • Injuries from accidents caused by symptoms of iron deficiency anemia such as weakness

  • Reduced physical activity

Does iron deficiency anemia shorten life expectancy?

Iron deficiency anemia has an excellent prognosis with treatment. Iron deficiency itself, prior to anemia, is gaining importance as a significant risk factor for poor health. Iron deficiency studies show that both iron deficiency and iron deficiency anemia significantly increase the risk of death (from any cause) in the long term. Anemia or iron deficiency was the cause of death for 5,254 people in 2019, according to the Centers for Disease Control and Prevention.

Doctors and other healthcare providers do not routinely screen for iron deficiency and anemia, but many health organizations advocate for annual screening. Ask your doctor about checking your iron level.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 2
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