Iron-Deficiency Anemia
Iron is very important for many body functions, including the production of hemoglobin, the protein in your blood that carries oxygen. Iron is also necessary for a healthy brain, immune system, muscles, cells, skin, hair, and nails.
Your body does not make iron on its own, so you have to get it from food, dietary supplements, or infusions. Iron from the food you ingest is absorbed into the body by the cells that line the gastrointestinal tract. The iron is then released into the blood stream, where a protein called transferrin attaches to it and delivers the iron to the liver. Iron is stored in the liver as ferritin and released to make new red blood cells in the bone marrow. When red blood cells stop functioning (after about 120 days in circulation), they are re-absorbed by the spleen. Iron from these old cells can also be recycled by the body.
Unfortunately, the body only absorbs a small fraction of the iron you ingest. If your body isn’t getting enough iron, this is called iron deficiency.
Am I at Risk?
The following groups of people are at highest risk for iron-deficiency anemia:
- People who have menstrual cycles, particularly if the cycles are prolonged and/or heavy
- People who are pregnant, post-partum, or breastfeeding
- People who have undergone major surgery or surgery, especially those with associated bleeding, or gastric bypass or duodenal surgeries
- People with gastrointestinal diseases such as celiac disease (sprue), inflammatory bowel diseases such as ulcerative colitis, or Crohn disease
- Vegetarians, vegans, and other people whose diets do not include iron-rich foods. Animal sources of iron are better absorbed than plant sources of iron.
- Children who consume more than 16 to 24 ounces a day of cow's milk in one day. Cow's milk not only contains little iron, but it can also decrease absorption of iron and irritate the intestinal lining causing chronic blood loss.
- Children born prematurely or exclusively breastfed require more iron for growth.
- People with bleeding disorders that lead to chronic nose bleeds, heavy menstrual cycles
- Children with behavioral/sensory issues who are unable to eat a variety of iron-rich food
- Athletes
Common Causes of Iron Deficiency
- Blood loss from tumors and other gastrointestinal (GI) tract diseases
- Chronic nosebleeds
- Blood loss from the kidneys or bladder
- Frequent blood donations
- Intravascular hemolysis, a condition in which red blood cells break down in the blood stream, releasing iron that is then lost in the urine. This can cause trauma to small blood vessels in the feet, so called "march hematuria." Intravascular hemolysis can also be seen in other conditions including damaged heart valves or rare disorders.
What Are the Signs and Symptoms of Iron-Deficiency Anemia?
Symptoms of iron-deficiency anemia may include:
- Being pale or having yellow "sallow" skin
- Unexplained fatigue or lack of energy
- Shortness of breath or chest pain, especially with physical activity
- Unexplained generalized weakness
- Rapid heartbeat
- Pounding or "whooshing" in the ears
- Headache, especially with activity
- Craving for ice or clay (picophagia)
- Sore or smooth tongue
- Brittle nails or hair loss
- Poor sleep
- Lightheadedness or dizziness
- Cold intolerance
- Restless leg syndrome
- Hair loss
How Is Iron-Deficiency Anemia Diagnosed?
Iron-deficiency anemia is diagnosed by blood tests that should include a complete blood count (CBC). Additional tests may be ordered to evaluate the levels of serum ferritin, iron, total iron-binding capacity, and/or transferrin. A patient with iron-deficiency anemia will have the following lab readings:
- Low hemoglobin and hematocrit
- Low mean cellular volume
- Low ferritin
- Low serum iron
- High transferrin or total iron-binding capacity
- Low transferrin saturation: The peripheral smear or blood slide may show small, oval-shaped cells with pale centers. In severe iron deficiency, the white blood count may be low and the platelet count may be high or low.
What Other Tests Will Be Done If Iron Deficiency Is Diagnosed?
Your doctor will decide if other tests are necessary. Iron deficiency is common in people who are menstruating or pregnant, children, and others with a diet history of excessive cow's milk or low iron-containing foods. Talk with your doctor about your diet and medical history. They can determine whether additional testing is needed. In some cases, a doctor may recommend:
- Testing for blood in the stool (fecal occult blood test)
- Looking for abnormalities in the gastrointestinal tract: Upper and lower endoscopy (looking into the stomach, esophagus, or colon with a tube), or capsule enteroscopy (swallowing a tiny camera that takes images of the gastrointestinal tract)
- Testing the urine for blood or hemoglobin
- A gynecologic evaluation for people with abnormal or increased menstrual blood losses
Sometimes it takes a specialist to find the cause of iron-deficiency anemia, or there may be another underlying condition. These may include blood disorders, such as thalassemia and sickle cell disease, or chronic infections or conditions, such as kidney failure, autoimmune diseases, and inflammatory disorders. When the cause of the anemia is unclear, your doctor may refer you to a hematologist, a medical specialist in blood disorders, for consultation and further evaluation.
How Is Iron Deficiency Treated?
Iron deficiency can be treated by increasing iron in the diet, taking oral iron supplements, or getting intravenous iron. Treatment depends on the cause and severity of your condition.
Iron-Rich Foods
- Red meat: beef, pork, or lamb, especially organ meats such as liver
- Poultry: chicken, turkey, and duck, especially liver and dark meat
- Fish, especially shellfish, sardines, and anchovies
- Leafy green members of the cabbage family including broccoli, kale, turnip greens, and collard greens
- Legumes, including lima beans, peas, pinto beans, and black-eyed peas
- Iron-enriched pastas, grains, rice, and cereals
Medicinal Iron
Patients with iron deficiency need more iron than the amount found in most daily multivitamin supplements. The amount of iron prescribed by your doctor will be in milligrams (mg) of elemental iron. Most people with iron deficiency need 18 to 62.5 mg of elemental iron per day. Iron supplements should not be taken more than once daily. Some people tolerate it better when it is taken every other day. There is no evidence that any one type of iron pill is better than the others, and the amount of elemental iron varies with different preparations. To be sure of the amount of iron in a product, check the packaging. Aside from elemental iron, you may see iron salt content listed, but this is different from elemental iron. To make sure you get the right dosage, show your iron supplements and any other vitamins you take to your doctor.
If you take antacids, take iron tablets two hours before or four hours after the antacid. Also, do not drink tea or coffee an hour before or after taking the iron pill. Dairy and high-calcium foods inhibit iron absorption, so avoid eating them two hours before and after taking iron supplements. Iron is best absorbed with vitamin C (ascorbic acid), which is found in foods such as oranges and lemon juice. Vitamin C tablets may be taken with iron pills. Possible side effects of iron tablets include abdominal discomfort, nausea, vomiting, diarrhea, constipation, and dark stools.
Intravenous Iron
Intravenous (IV) iron may be necessary to treat iron deficiency in patients who do not absorb iron well in the gastrointestinal tract, patients with severe iron deficiency or chronic blood loss, or patients who cannot tolerate oral iron. If you need IV iron, your doctor may refer you to a hematologist to supervise the treatments.
Large doses of iron can be given at one time when using iron dextran and ferric derisomaltose. Iron sucrose and ferric gluconate require more frequent doses spread over several weeks. The most common reaction to IV iron is a nonspecific infusion reaction that can resolve on its own in 15 minutes. Some patients may have an allergic reaction to IV iron, so a test dose may be administered before the first infusion. Allergic reactions are more common with iron dextran and may necessitate switching to a different preparation. Some patients may have joint and muscle pain plus the urine may be dark the next day. Severe allergic reactions are very rare — occurring in less than one in 10,000 patients. Severe side effects other than allergic reactions are rare and include urticaria (hives), pruritus (itching), and muscle and joint pain.
Blood Transfusions
Red blood cell transfusions may be given to patients with severe iron-deficiency anemia who are actively bleeding or have significant symptoms such as chest pain, shortness of breath, or weakness. Transfusions are given to replace deficient red blood cells and will not completely correct the iron deficiency. Red blood cell transfusions will only provide temporary improvement. It is important to find out why you are anemic and treat the cause as well as the symptoms.
Am I a Good Candidate for Donating Blood if I’m Iron Deficient?
You may not be a good candidate for donating blood if you are iron deficient. Men typically have about 1,000 mg of stored iron, while women have about 300 mg. In the average blood donation session, you lose 220 to 250 mg of iron, and it can take up to 24 to 30 weeks for your body to replenish the iron lost. Iron is essential to replace the blood cells you lose through donation; if your iron levels are low, it is much more difficult for your body to recover after donation.
Blood donation centers will assess your levels of hemoglobin, but not ferritin, before donation. Hemoglobin is a protein that carries iron and low levels may signify anemia, when insufficient oxygen is carried from the lungs to other organs. While blood donation centers will ask you to wait to donate if your hemoglobin levels are low, it is important to note that they will not measure your levels of ferritin, the protein that stores iron in the blood and signifies iron deficiency. It is possible to be anemic, but not iron deficient, and vice versa. In fact, iron deficiency without anemia (normal hemoglobin levels and low ferritin levels), is nearly twice as common as iron deficiency with anemia (low hemoglobin levels and low ferritin levels), which affects around 1.2 billion people.
Talk to your doctor about assessing and supporting your iron levels, especially if you are considering blood donation or have recently donated blood. It is possible to become iron deficient after giving blood because your iron stores are depleted during donation. Your doctor can help you determine if you are a good candidate for donation, what steps you can take to maintain healthy iron stores, and how to restore them after donation.
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