Iron Deficiency Anaemia

Iron deficiency anaemia is the most common type of anaemia worldwide, affecting millions of people when their bodies lack enough iron to produce healthy red blood cells that carry oxygen throughout the body.

Table of contents

• What is iron deficiency anaemia?
• How iron deficiency develops
• Signs and symptoms
• Causes and risk factors
• How it is diagnosed
• Treatment options
• Dietary recommendations
• Possible complications
• Prevention

What is iron deficiency anaemia?

Iron deficiency anaemia is a common blood condition that happens when your body does not have enough iron to make hemoglobin, which is the substance in red blood cells that carries oxygen throughout your body.^[1] Without enough iron, your body cannot produce sufficient healthy red blood cells, which means your tissues and organs do not get the oxygen they need to function properly.^[2]

Iron is essential for many body functions beyond making red blood cells. It helps maintain a healthy immune system, supports proper muscle function, and is necessary for healthy skin, hair, and nails.^[3] Your body normally gets iron through your diet and reuses iron from old red blood cells. When these sources cannot keep up with your body’s needs, iron deficiency develops.^[5]

This condition is the single most common nutritional deficiency worldwide. It affects about one-third of the global population and accounts for approximately half of all anaemia cases.^[9] In the United States, iron deficiency anaemia affects approximately 5% of women and 2% of men.^[1]

How iron deficiency develops

Iron deficiency anaemia develops gradually through three distinct stages as your body’s iron stores become depleted.^[2]

In the first stage, your iron stores begin to decrease, but this has not yet affected your red blood cells. You may not notice any symptoms at this point. During the second stage, when iron stores are low, your body changes the way it processes red blood cells. Your bone marrow, which is the soft tissue inside bones where blood cells are made, begins producing red blood cells without enough hemoglobin.^[2]

The third stage occurs when hemoglobin drops below the normal range. At this point, you may begin to experience signs and symptoms of iron deficiency anaemia.^[2] Red blood cells normally circulate through your body for about 120 days before being absorbed by the spleen. Iron from these old cells is then recycled by the body.^[3]

Signs and symptoms

Iron deficiency anaemia often starts with mild symptoms that are easy to overlook. However, as the condition worsens, the symptoms become more noticeable.^[1]

The most common symptoms include extreme tiredness, weakness, and pale skin. Many people experience shortness of breath, chest pain, or a fast or pounding heartbeat, especially during physical activity.^[1] Headaches, dizziness, and feeling lightheaded when standing up are also frequent complaints.^[2]

You may notice cold hands and feet, as your body struggles to deliver enough oxygen to your extremities. Some people develop an irritated or sore tongue, while others experience brittle nails or unusual nail shapes.^[1] Hair loss, particularly noticing more hair coming out when brushing or washing, can also occur.^[7]

Less common but notable symptoms include pica, which is a craving to eat non-food items such as ice, dirt, clay, paper, or chalk.^[1] Some people develop unusual cravings for specific smells, such as rubber, detergents, or cleaning agents. Children, in particular, may lose their appetite or refuse to eat.^[1] Other possible symptoms include difficulty swallowing, painful sores at the corners of the mouth, hearing ringing or buzzing sounds in your head, and restless legs syndrome.^[7]

Causes and risk factors

Iron deficiency anaemia develops when your body loses more iron than it can absorb or when you do not get enough iron from your diet.^[5]

The most common cause is blood loss. For women of childbearing age, heavy or prolonged menstrual periods are a frequent cause of iron deficiency.^[4] For men and postmenopausal women, bleeding in the digestive tract is the most common reason. This can result from conditions such as ulcers, gastritis, esophageal inflammation, hemorrhoids, or cancers of the esophagus, stomach, small bowel, or colon.^[3]

Long-term use of certain medications can lead to bleeding. These include aspirin, ibuprofen, and other nonsteroidal anti-inflammatory drugs that can cause gastrointestinal bleeding.^[4] Blood loss can also occur from chronic nosebleeds, bleeding from the kidneys or bladder, or frequent blood donations.^[3]

Problems absorbing iron from your diet represent another important cause. Certain conditions make it harder for your body to absorb iron, including celiac disease, which is an autoimmune disorder that damages the small intestine, Crohn’s disease, ulcerative colitis, and gastric bypass surgery.^[2] Taking too many antacids or certain antibiotics like tetracycline can also interfere with iron absorption.^[5]

Not getting enough iron in your diet can contribute to iron deficiency, particularly if you are a strict vegetarian or vegan. Plant-based iron is not absorbed as well as iron from meat, poultry, and fish.^[3] Children who drink more than 16 to 24 ounces of cow’s milk per day are at risk because cow’s milk contains little iron, can decrease iron absorption, and may irritate the intestinal lining, causing chronic blood loss.^[3]

Certain groups of people face a higher risk of developing iron deficiency anaemia. Women who are pregnant or breastfeeding need extra iron because their bodies require more to support the developing baby or produce breast milk.^[3] People who have undergone major surgery, particularly gastrointestinal or weight loss surgery, are at increased risk.^[2] Those who engage in vigorous endurance sports, particularly running, can lose iron through their gastrointestinal tract and through the breakdown of red blood cells.^[4]

How it is diagnosed

If you or your child develop symptoms that might indicate iron deficiency anaemia, it is important to see your healthcare provider. Do not try to diagnose or treat the condition on your own, as taking iron supplements without proper testing can be harmful.^[1]

Your healthcare provider will ask about your lifestyle and medical history, then typically order blood tests to confirm the diagnosis.^[7] The most common test is a complete blood count, which checks if the number of red blood cells you have is normal and also looks at other types of cells in your blood. You do not need to do anything special to prepare for this test.^[7]

The blood tests will examine several important factors. With iron deficiency anaemia, red blood cells are typically smaller and paler than usual.^[8] Your provider will measure your hematocrit, which is the percentage of blood volume made up by red blood cells, and your hemoglobin level. Lower than standard hemoglobin levels indicate anaemia.^[8]

A key test measures your ferritin level. Ferritin is a protein that helps store iron in your body, and a low ferritin level indicates low iron stores.^[8] While levels below 15 nanograms per milliliter confirm iron deficiency, using a cutoff of 30 nanograms per milliliter improves the accuracy of diagnosis.^[9] Other tests may measure serum iron, total iron-binding capacity, and transferrin levels to provide a complete picture of your iron status.^[3]

If blood tests confirm iron deficiency anaemia, your healthcare provider may recommend additional tests to find the underlying cause. These might include an endoscopy to check for bleeding in your upper digestive tract, a colonoscopy to examine your lower intestinal tract, or an ultrasound to look for causes of heavy menstrual bleeding such as uterine fibroids.^[8]

Treatment options

The good news is that iron deficiency anaemia can be treated effectively. Your healthcare provider will create a treatment plan tailored to your specific needs.^[2]

The first line of treatment is usually oral iron supplements, most commonly ferrous sulfate. Although the traditional dose is 325 milligrams three times daily, lower doses may be just as effective and cause fewer side effects.^[13] You will typically need to take iron supplements for about six months. The first six weeks work to improve or resolve your anaemia, while the remaining time helps rebuild your body’s iron stores in the bone marrow.^[5]

Taking iron supplements correctly can improve how well they work. Iron is absorbed best when taken in the morning before eating, with orange juice or a vitamin C supplement, as vitamin C helps your body absorb iron better.^[6] However, you should avoid taking iron with tea, coffee, milk, or dairy products, as these can interfere with absorption.^[7]

Iron supplements can cause side effects in some people, including nausea, constipation or diarrhea, stomach pain, heartburn, and darker than usual stools.^[7] Taking the tablets with or soon after food can help reduce these side effects. It is important to keep taking the supplements even if you experience side effects, as your body needs the iron to recover.^[7]

For some patients, oral iron supplements are not sufficient or cannot be tolerated. In these cases, your healthcare provider may recommend intravenous iron, which is iron given directly into a vein.^[11] This approach is particularly useful for people who cannot absorb iron through their digestive tract, those who have lost a large amount of blood, or those who have conditions where blood loss exceeds the intestinal ability to absorb iron.^[11]

In addition to iron supplementation, it is crucial to treat the underlying cause of your iron deficiency. This might involve addressing heavy menstrual periods with medication, treating digestive conditions causing bleeding, or managing other health problems contributing to the deficiency.^[7] Your healthcare provider will monitor your progress with repeat blood tests to ensure your iron levels are returning to normal.^[7]

Important safety note: Keep iron supplements away from babies and young children. An overdose of iron in a young child can be fatal.^[6]

Dietary recommendations

Eating a diet rich in iron is an important part of treating and preventing iron deficiency anaemia. Your healthcare provider may recommend including more iron-rich foods in your meals.^[1]

Foods high in iron include dark-green leafy vegetables like watercress, spinach, and curly kale. Meat, particularly red meat and liver, is an excellent source of easily absorbed iron. Other good sources include chicken, turkey, pork, and fish.^[7] Cereals and bread with extra iron added (fortified products) can boost your intake. Dried fruits such as apricots, prunes, and raisins provide iron, as do beans, peas, and lentils. Nuts, including almonds, pistachios, and sesame seeds, are also beneficial.^[5]

The type of iron in food matters. Heme iron, found in meat and animal products, is absorbed much better by your body than non-heme iron from plants.^[15] However, you can improve iron absorption from plant foods by pairing them with vitamin C-rich foods. For example, eating strawberries or tomatoes with iron-rich vegetables, or having fish with lemon juice, helps your body absorb more iron.^[7]

How you prepare food can also affect its iron content. Cooking food in a cast iron skillet can increase the amount of iron in your meals.^[20]

Some foods and drinks can interfere with iron absorption and should be limited, especially around mealtimes. These include milk and dairy products like ice cream and butter, even though they are high in calcium.^[20] Tea, coffee, and foods high in tannins, such as dark chocolate, pomegranate, and red wine, can make iron absorption harder. You do not have to avoid these completely, but consider waiting a few hours after eating an iron-rich meal before consuming them.^[20] Whole grain cereals contain substances called phytates that can also reduce iron absorption.^[7]

Possible complications

If iron deficiency anaemia is not treated, it can lead to serious health problems. The lack of oxygen delivered to your body’s tissues can affect your heart and lungs.^[7]

Severe or untreated iron deficiency anaemia may increase your risk of developing heart complications, including an abnormally fast heartbeat or heart failure. Your heart has to work harder to pump blood when there are fewer red blood cells to carry oxygen, which can eventually damage the heart.^[2]

Other complications include brain fog and difficulty concentrating, restless legs syndrome, and a weakened immune system that makes you more vulnerable to illness and infection.^[2] In children, iron deficiency anaemia can cause growth delays and developmental problems.^[2]

For pregnant women, iron deficiency anaemia poses additional risks. It can lead to complications before and after birth, affecting both mother and baby.^[7] This is why screening and treatment during pregnancy are so important.

Prevention

Many cases of iron deficiency anaemia can be prevented through proper nutrition and addressing risk factors early.^[7]

Eating a well-balanced diet that includes iron-rich foods is the foundation of prevention. Make sure your diet contains a variety of iron sources, including lean meats, fish, fortified cereals, beans, and leafy green vegetables. Pairing these foods with vitamin C sources will help your body absorb the iron more effectively.^[7]

Certain groups need to pay special attention to their iron intake. Pregnant women should take prenatal vitamins that contain extra iron, as they often cannot get enough from their diet alone.^[5] Women who are breastfeeding also need additional iron.^[2] If you are a vegetarian or vegan, work with your healthcare provider or a dietitian to ensure you are getting adequate iron from plant sources.^[3]

If you have heavy menstrual periods, talk to your healthcare provider about treatment options to reduce blood loss. If you donate blood frequently, be aware that this increases your risk of iron deficiency and discuss appropriate screening and supplementation with your provider.^[2]

Regular health checkups can help catch iron deficiency early, especially if you are in a high-risk group. While routine screening is not recommended for all adults, pregnant women should be screened for iron deficiency anaemia, and children should be screened at one year of age.^[9]