Iron deficiency anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types and causes of anemia.
Iron deficiency anemia occurs when your body does not have enough iron. Iron helps make red blood cells. Iron deficiency anemia is the most common form of anemia.
Reticulocytes
In the presence of some anemias, the body increases production of red blood cells (RBCs), and sends these cells into the bloodstream before they are mature. These slightly immature cells are called reticulocytes, and are characterized by a network of filaments and granules. Reticulocytes normally make up 1% of the total RBC count, but may exceed levels of 4% when compensating for anemia.
Causes
Iron deficiency anemia - Animation
To be anemic means that there aren't enough red blood cells flowing throughout your body. Red blood cells carry oxygen throughout your body, so if you're anemic, everything from your brain, to your heart, to your muscles aren't getting enough oxygen to run properly. Iron is a key part of red blood cells. When your body doesn't have enough iron, it'll make fewer red blood cells or make cells that are just too small. If you lose enough iron, you'll wind up with iron deficiency anemia - the most common form of anemia. So, what causes iron deficiency anemia? There are basically three main ways you can become iron deficient. First, bleeding can cause you to lose more blood cells and iron than your body can replace. Bleeding due to ulcers, cancers, taking aspirin or other medicines can cause anemia. In women, this can happen because of heavy or frequent menstrual periods. The second way, your body isn't properly absorbing iron, perhaps, due to an intestinal disease. Some surgeries, like gastric bypass, can lead to anemia. You can also develop anemia if you take too many antacids that contain calcium. Lastly and much less common, is because of inadequate iron in your diet. We see this in strict vegetarians and older folks who simply just don't eat enough food. In many cases, mild iron deficiency anemia comes on so gradually that you may not even know you're anemic. Symptoms of mild anemia are subtle and include feeling grumpy, weak or tired more often than usual and getting headaches or perhaps having problems concentrating. But as the anemia gets worse, you may develop a blue color to the whites of your eyes, light-headedness when you go to stand up and you may look pale or experience shortness of breath. To find out if you've got iron-deficiency anemia. See your doctor; your doctor will start with a Complete Blood Count or CBC test. That'll tell you and your doctor your white, red blood cell and platelet counts. If you're anemic and have small red blood cells, that suggests iron deficiency anemia, so iron studies like serum iron, total iron binding capacity and ferritin level tests should be done. So, what steps can you take -- It's important that your diet include enough iron. Red meat, chicken, turkey. liver, and egg yolks are important sources of iron. Flour, bread, and some cereals are fortified with iron. Sometimes people with anemia take iron supplements to build up iron stores in their bodies. But the thing is - It's not enough just to take extra iron at your doctor's direction...Your doctor needs to find out WHY you've got iron deficiency anemia and treat that underlying cause.
Red blood cells bring oxygen to your body's tissues. Red blood cells are made in your bone marrow. Red blood cells circulate through your body for 3 to 4 months. Parts of your body, such as your spleen, remove old blood cells.
Iron is a key part of red blood cells. Without iron to make hemoglobin, your blood cannot carry oxygen effectively. Your body normally gets iron through your diet. It also reuses iron from old red blood cells.
Iron deficiency anemia develops when your body's iron stores run low. This can occur because:
- You lose more blood cells and iron than your body can replace
- Your body does not absorb iron well
- Your body is able to absorb iron, but you are not eating enough foods that contain iron
- Your body needs more iron than normal (such as if you are pregnant or breastfeeding)
Bleeding can cause iron loss. Common causes of bleeding are:
- Heavy, long, or frequent menstrual periods
- Cancer in the esophagus, stomach, small bowel, or colon
Colon
Colorectal cancer is cancer that starts in the large intestine (colon) or the rectum (end of the colon). It is also sometimes simply called colon ca...
Read Article Now Book Mark Article - Esophageal varices, often from cirrhosis
Esophageal varices
The esophagus (food pipe) is the tube that connects your throat to your stomach. Varices are enlarged veins that may be found in the esophagus in pe...
Read Article Now Book Mark Article - The use of aspirin, ibuprofen, or medicines that may thin the blood for a long time, which can cause gastrointestinal bleeding
- Peptic ulcer disease
Peptic ulcer disease
A peptic ulcer is an open sore or raw area in the lining of the stomach or intestine. There are two types of peptic ulcers:Gastric ulcer -- occurs in...
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Your body may not absorb enough iron in your diet due to:
- Celiac disease
Celiac disease
Celiac disease is an autoimmune condition that damages the lining of the small intestine. This damage comes from a reaction to eating gluten. This ...
Read Article Now Book Mark Article - Crohn disease
Crohn disease
Crohn disease is a disease where parts of the digestive tract become inflamed. It most often involves the lower end of the small intestine and the be...
Read Article Now Book Mark Article - Gastric bypass surgery
Gastric bypass surgery
Gastric bypass is surgery that helps you lose weight by changing how your stomach and small intestine handle the food you eat. After the surgery, you...
Read Article Now Book Mark Article - Taking too many antacids or too much of the antibiotic tetracycline
You may not get enough iron in your diet if:
- You are a strict vegetarian
- You do not eat enough foods that contain iron
Symptoms
You may have no symptoms if the anemia is mild.
Most of the time, symptoms are mild at first and develop slowly. Symptoms may include:
- Feeling weak or tired more often than usual, or with exercise
- Headaches
- Dizziness
- Palpitations
- Problems concentrating or thinking
As the anemia gets worse, symptoms may include:
- Brittle nails
Brittle nails
Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails.
Read Article Now Book Mark Article - Blue color to the whites of the eye
- Desire to eat ice or other non-food things (pica)
Pica
Pica is a pattern of eating non-food materials, such as dirt or paper.
Read Article Now Book Mark Article - Feeling lightheaded when you stand up
- Pale skin color
Pale skin color
Paleness is an abnormal loss of color from normal skin or mucous membranes.
Read Article Now Book Mark Article - Shortness of breath
Shortness of breath
Breathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough air
Read Article Now Book Mark Article - Sore or inflamed tongue
- Mouth ulcers
- Uncontrolled movement of legs (during sleep)
- Hair loss
Symptoms of the conditions associated with bleeding that cause iron deficiency anemia include:
- Dark, tar-colored stools or blood in the stool
- Heavy menstrual bleeding
- Pain in the upper belly (from ulcers)
Exams and Tests
To diagnose anemia, your health care provider may order these blood tests:
- Complete blood count (CBC)
- Reticulocyte count
Hemoglobin
Hemoglobin is the most important component of red blood cells. It is composed of a protein called heme, which binds oxygen. In the lungs, oxygen is exchanged for carbon dioxide. Abnormalities of an individual's hemoglobin value can indicate defects in the normal balance between red blood cell production and destruction. Both low and high values can indicate disease states.
To check iron levels, your provider may order:
- Serum iron level
Serum iron
A serum iron test measures how much iron is in your blood.
Read Article Now Book Mark Article - Total iron binding capacity (TIBC) in the blood
Total iron binding capacity
Total iron binding capacity (TIBC) is a blood test to see if you have too much or too little iron in your blood. Iron moves through the blood attach...
Read Article Now Book Mark Article - Serum ferritin
Serum ferritin
The ferritin blood test measures the level of ferritin in the blood. Ferritin is a protein inside your cells that stores iron. It allows your body ...
Read Article Now Book Mark Article - Bone marrow biopsy (if the diagnosis is not clear)
Bone marrow biopsy
A bone marrow biopsy is the removal of marrow from inside bone. Bone marrow is the soft tissue inside bones that helps form blood cells. It is foun...
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To check for causes of blood loss, your provider may order:
- Colonoscopy
Colonoscopy
A colonoscopy is an exam that views the inside of the colon (large intestine) and rectum, using a tool called a colonoscope. The colonoscope has a sm...
Read Article Now Book Mark Article - Fecal occult blood test
Fecal occult blood test
The stool guaiac test looks for hidden (occult) blood in a stool sample. It can find blood even if you cannot see it yourself. It is the most commo...
Read Article Now Book Mark Article - Upper endoscopy
Upper endoscopy
Esophagogastroduodenoscopy (EGD) is a test to examine the lining of the esophagus, stomach, and first part of the small intestine (the duodenum)....
Read Article Now Book Mark Article - Tests to detect sources of blood loss in the urinary tract or uterus
Treatment
Treatment may include taking iron supplements and eating iron-rich foods.
Taking iron supplements
Eating iron rich foods is a key part of treating anemia caused by low iron levels. You may also need to take iron supplements as well to rebuild iro...
Read Article Now Book Mark ArticleIron-rich foods
Iron is a mineral found in every cell of the body. Iron is considered an essential mineral because it is needed to make hemoglobin, a part of blood ...
Read Article Now Book Mark ArticleIron supplements (most often ferrous sulfate) build up the iron stores in your body. Most of the time, your provider will measure your iron level before you start supplements.
If you cannot take iron by mouth, you may need to take it through a vein (intravenous) or by an injection into the muscle.
Intravenous
Intravenous means "within a vein. " Most often it refers to giving medicines or fluids through a needle or tube inserted into a vein. This allows th...
Read Article Now Book Mark ArticlePregnant and breastfeeding women will need to take extra iron because they often cannot get enough iron from their normal diet.
Often your anemia will improve or resolve with 6 weeks of iron therapy. You will need to keep taking iron for another 6 months to replace your body's iron stores in your bone marrow.
Iron supplements are mostly well tolerated, but may cause:
- Nausea
- Vomiting
- Constipation
Iron-rich foods include:
- Chicken and turkey
- Dried lentils, peas, and beans
- Fish
- Meats (liver is the highest source)
- Soybeans, baked beans, chickpeas
- Whole-grain bread
Other sources include:
- Oatmeal
- Raisins, prunes, apricots, and peanuts
- Spinach, kale, and other greens
Vitamin C helps your body to absorb iron. Good sources of vitamin C are:
- Oranges
- Grapefruits
- Kiwi
- Strawberries
- Broccoli
- Tomatoes
Outlook (Prognosis)
With treatment, the outcome is likely to be good, but it does depend on the cause.
When to Contact a Medical Professional
Contact your provider if:
- You have symptoms of iron deficiency
- You notice blood or a black tar-appearance in your stool
Prevention
A balanced diet should include enough iron. Food sources of iron are listed above. If advised by your provider, take iron supplements.
Reviewed By
John Roberts, MD, Professor of Internal Medicine (Medical Oncology), Yale Cancer Center, New Haven, CT. He is board certified in Internal Medicine, Medical Oncology, Pediatrics, Hospice and Palliative Medicine. Review provided by VeriMed Healthcare Network. Internal review and update on 02/03/2024 by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Camaschella C. Disorders of iron homeostasis: iron deficiency and overload. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 37.
Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 33.
Means RT Jr. Approach to the anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 144.
National Heart, Lung, and Blood Institute website. Iron-deficiency anemia. www.nhlbi.nih.gov/health/anemia/iron-deficiency-anemia. Updated March 24, 2022. Accessed February 1, 2024.