What is iron deficiency anemia

Iron deficiency anemia is a condition where a lack of iron in the body leads to a reduction in the number of healthy red blood cells. Red blood cells carry oxygen to the body’s tissues.

Iron deficiency anemia is a common type of anemia and it has many causes – particularly in women, premature or very small babies, children and people on restricted diets. Symptoms are related to the overall decrease in the number of red blood cells (RBCs) and the level of hemoglobin. If the iron deficiency anemia is mild to moderate, there may be no signs or symptoms. In addition to the most common signs and symptoms, there are some that are more unique to iron deficiency and may appear as iron stores in the body are chronically depleted. These may include:

• Brittle or spoon-shaped nails
• Swollen or sore tongue
• Cracks or ulcers at the corners of the mouth
• Difficulty in swallowing
• Craving to eat unusual non-food substances such as ice or dirt (also known as “pica”)

Iron is an essential trace element and is necessary for the production of healthy red blood cells. It is one component of heme, a part of hemoglobin, which is the protein in red blood cells that binds to oxygen and allows red blood cells to transport oxygen throughout the body. If not enough iron is taken in compared to what the body needs, then iron stored in the body begins to be used up. As iron stores are depleted, the body makes fewer red blood cells with decreased amounts of hemoglobin in them, resulting in anemia.

What happens if you don’t get enough iron ?

In the short term, getting too little iron does not cause obvious symptoms. The body uses its stored iron in the muscles, liver, spleen, and bone marrow. But when levels of iron stored in the body become low, iron deficiency anemia sets in. Red blood cells become smaller and contain less hemoglobin. As a result, blood carries less oxygen from the lungs throughout the body.

Symptoms of iron deficiency anemia include tiredness and lack of energy, GI (gastrointestinal) upset, poor memory and concentration, and less ability to fight off germs and infections or to control body temperature. Infants and children with iron deficiency anemia might develop learning difficulties.

Iron deficiency without anemia

Although iron deficiency is not common in the United States, iron deficiency is the most common known form of nutritional deficiency worldwide. It can occur in people who do not eat meat, poultry, or seafood; lose blood; have gastrointestinal diseases that interfere with nutrient absorption; or eat poor diets.Its prevalence is highest among young children and women of childbearing age (particularly pregnant women). In children, iron deficiency causes developmental delays and behavioral disturbances, and in pregnant women, it increases the risk for a preterm delivery and delivering a low-birthweight baby. In the past three decades, increased iron intake among infants has resulted in a decline in childhood iron-deficiency anemia in the United States. As a consequence, the use of screening tests for anemia has become a less efficient means of detecting iron deficiency in some populations. For women of childbearing age, iron deficiency has remained prevalent ¹.

Iron deficiency has negative effects on work capacity and on motor and mental development in infants, children, and adolescents, and maternal iron deficiency anemia might cause low birthweight and preterm delivery ², ³, ⁴. Although iron deficiency is more common in developing countries, a significant prevalence was observed in the United States during the early 1990s among certain populations, such as toddlers and females of childbearing age ⁵.

Centers for Disease Control and Prevention (CDC) has published recommendations to prevent iron deficiency in the United States ⁶. To prevent iron deficiency, vulnerable populations should be encouraged to eat iron-rich foods and breast-feed or use iron-fortified formula for infants.

The definition of iron deficiency was an abnormal value for at least two of the following three indicators: serum ferritin, transferrin saturation, and free erythrocyte protoporphyrin. Persons with iron deficiency and a low hemoglobin value were considered to have iron deficiency anemia ⁵.

The estimated prevalence of iron deficiency was greatest among toddlers aged 1–2 years (7%) and adolescent and adult females aged 12–49 years (9%–16%) ⁷. The prevalence of iron deficiency was approximately two times higher among non-Hispanic black and Mexican-American females (19%–22%) than among non-Hispanic white females (10%).

Complications of iron deficiency anemia

Mild iron deficiency anemia usually doesn’t cause complications. However, left untreated, iron deficiency anemia can become severe and lead to health problems, including the following:

• Heart problems. Iron deficiency anemia may lead to a rapid or irregular heartbeat. Your heart must pump more blood to compensate for the lack of oxygen carried in your blood when you’re anemic. This can lead to an enlarged heart or heart failure.
• Problems during pregnancy. In pregnant women, severe iron deficiency anemia has been linked to premature births and low birth weight babies. But the condition is preventable in pregnant women who receive iron supplements as part of their prenatal care.
• Growth problems. In infants and children, severe iron deficiency can lead to anemia as well as delayed growth and development. Additionally, iron deficiency anemia is associated with an increased susceptibility to infections.

Iron deficiency anemia causes

Iron is stored in your liver, spleen and bone marrow and is vital for mental and physical well-being.

While most of the body’s iron is recycled from red blood cells that have died, a small but essential amount comes from food. (Iron is one of the many minerals found in food.)

Iron deficiency anemia occurs when your body doesn’t have enough iron to produce hemoglobin. Hemoglobin is the part of red blood cells that gives blood its red color and enables the red blood cells to carry oxygenated blood throughout your body.

If you aren’t consuming enough iron, or if you’re losing too much iron, your body can’t produce enough hemoglobin, and iron deficiency anemia will eventually develop.

The reasons for getting iron deficiency anemia include the following.

Loss of iron as a result of blood loss, for example from:

• heavy periods;
• stomach and bowel problems (including ulcers, bowel polyps, hemorrhoids or cancer), which can go unnoticed because the blood loss may be very slow; or
  regular use of medicines that can cause stomach bleeding (for example, aspirin and non-steroidal anti-inflammatory medicines – NSAIDs).

Inadequate intake of iron in the diet to meet the demands of the body, due to:

• lack of iron in the diet over a long period of time (vegetarians and vegans are at increased risk);
• fast growth in children;
• being born early (premature);
• being pregnant — the mother’s iron stores go to her baby; or
• excessive exercise — where the body needs more iron than usual and iron is also lost in sweat.

Inadequate absorption of iron from the gut, due to:

• being unable to absorb iron in the bowel, for example in Crohn’s disease or untreated Celiac disease; or
• surgery that involves removing or bypassing part of the stomach or small bowel (for example, some types of weight loss surgery).

Risk factors of iron deficiency anemia

These groups of people may have an increased risk of iron deficiency anemia:

• Women. Because women lose blood during menstruation, women in general are at greater risk of iron deficiency anemia.
• Infants and children. Infants, especially those who were low birth weight or born prematurely, who don’t get enough iron from breast milk or formula may be at risk of iron deficiency. Children need extra iron during growth spurts. If your child isn’t eating a healthy, varied diet, he or she may be at risk of anemia.
• Vegetarians. People who don’t eat meat may have a greater risk of iron deficiency anemia if they don’t eat other iron-rich foods.
• Frequent blood donors. People who routinely donate blood may have an increased risk of iron deficiency anemia since blood donation can deplete iron stores. Low hemoglobin related to blood donation may be a temporary problem remedied by eating more iron-rich foods. If you’re told that you can’t donate blood because of low hemoglobin, ask your doctor whether you should be concerned.

How Can Iron-Deficiency Anemia Be Prevented ?

Eating a well-balanced diet that includes iron-rich foods may help you prevent iron-deficiency anemia.

Taking iron supplements also may lower your risk for the condition if you’re not able to get enough iron from food. Large amounts of iron can be harmful, so take iron supplements only as your doctor prescribes.

Infants and young children and women are the two groups at highest risk for iron-deficiency anemia. Special measures can help prevent the condition in these groups.

Infants and Young Children

A baby’s diet can affect his or her risk for iron-deficiency anemia. For example, cow’s milk is low in iron. For this and other reasons, cow’s milk isn’t recommended for babies in their first year. After the first year, you may need to limit the amount of cow’s milk your baby drinks.

After age 6 months, start feeding your baby iron-fortified cereals or pureed meats at least twice a day to boost iron intake. After one year, be sure children don’t drink more than 20 ounces (591 milliliters) of milk a day. Too much milk often takes the place of other foods, including those that are rich in iron.

Also, babies need more iron as they grow and begin to eat solid foods. Talk with your child’s doctor about a healthy diet and food choices that will help your child get enough iron.

Your child’s doctor may recommend iron drops. However, giving a child too much iron can be harmful. Follow the doctor’s instructions and keep iron supplements and vitamins away from children. Asking for child-proof packages for supplements can help prevent overdosing in children.

Because recent research supports concerns that iron deficiency during infancy and childhood can have long-lasting, negative effects on brain health, the American Academy of Pediatrics recommends testing all infants for anemia at 1 year of age.

Women and Girls

Women of childbearing age may be tested for iron-deficiency anemia, especially if they have:

• A history of iron-deficiency anemia
• Heavy blood loss during their monthly periods
• Other risk factors for iron-deficiency anemia

The Centers for Disease Control and Prevention (CDC) has developed guidelines for who should be screened for iron deficiency, and how often:

• Girls aged 12 to 18 and women of childbearing age who are not pregnant: Every 5 to 10 years.
• Women who have risk factors for iron deficiency: Once a year.
• Pregnant women: At the first prenatal visit.

For pregnant women, medical care during pregnancy usually includes screening for anemia. Also, your doctor may prescribe iron supplements or advise you to eat more iron-rich foods. This not only will help you avoid iron-deficiency anemia, but also may lower your risk of having a low-birth-weight baby.

You can reduce your risk of iron deficiency anemia by choosing iron-rich foods.

Choose iron-rich foods

Foods rich in iron include:

• Red meat, pork and poultry
• Seafood
• Beans
• Dark green leafy vegetables, such as spinach
• Dried fruit, such as raisins and apricots
• Iron-fortified cereals, breads and pastas
• Peas

Your body absorbs more iron from meat than it does from other sources. If you choose to not eat meat, you may need to increase your intake of iron-rich, plant-based foods to absorb the same amount of iron as does someone who eats meat.

Choose foods containing vitamin C to enhance iron absorption

You can enhance your body’s absorption of iron by drinking citrus juice or eating other foods rich in vitamin C at the same time that you eat high-iron foods. Vitamin C in citrus juices, like orange juice, helps your body to better absorb dietary iron.

Vitamin C is also found in:

• Broccoli
• Grapefruit
• Kiwi
• Leafy greens
• Melons
• Oranges
• Peppers
• Strawberries
• Tangerines
• Tomatoes

How much iron do you need ?

The amount of iron you need each day depends on your age, your sex, and whether you consume a mostly plant-based diet. Average daily recommended amounts are listed below in milligrams (mg). Vegetarians who do not eat meat, poultry, or seafood need almost twice as much iron as listed in the table because the body doesn’t absorb nonheme iron in plant foods as well as heme iron in animal foods.

Most people in America get enough iron. However, certain groups of people are more likely than others to have trouble getting enough iron:

• Teen girls and women with heavy periods.
• Pregnant women and teens.
• Infants (especially if they are premature or low-birthweight).
• Frequent blood donors.
• People with cancer, gastrointestinal (GI) disorders, or heart failure.

Iron deficiency anemia signs and symptoms

The symptoms of iron deficiency anemia are caused by a lack of oxygen being supplied to the tissues.

Iron deficiency anemia signs and symptoms may include:

• Tiredness;
• Weakness;
• Short of breath (especially when exercising);
• Light-headed or dizziness;
• Have headaches or become irritable;
• Extreme fatigue
• Pale skin
• Chest pain, fast heartbeat or shortness of breath
• Cold hands and feet
• Inflammation or soreness of your tongue
• Brittle nails
• Unusual cravings for non-nutritive substances, such as ice, dirt or starch
• Poor appetite, especially in infants and children with iron deficiency anemia

In addition, your skin and the inside of your mouth may be pale.

Older people with anemia may get angina (pain in the chest) because the heart has to work harder to supply enough oxygen to the body.

Signs and symptoms of iron deficiency include the following:

• In the early stages of iron deficiency you may have no symptoms or just mild fatigue.
• You may be more likely to pick up infections.
• Eventually, your nails can become spoon-shaped and brittle, the corners of your mouth may crack, and you may have difficulty swallowing.
• Some people with low iron levels, especially children, may have difficulty with concentration and memory, or have trouble learning. Iron deficiency anemia in children may cause problems with development.
• Some people get cravings for unusual substances, such as ice or earth (soil).

How is iron deficiency anemia diagnosed?

Your doctor will ask about your symptoms and perform a physical examination, looking for signs of anemia and iron deficiency.

If they suspect iron deficiency anemia, they may also ask about your diet and other possible causes.

If your anemia is not severe you may not have any symptoms and may be diagnosed following a routine blood test.

Your doctor will diagnose iron-deficiency anemia based on your medical history, a physical exam, and the results from tests and procedures.

Once your doctor knows the cause and severity of the condition, he or she can create a treatment plan for you.

Mild to moderate iron-deficiency anemia may have no signs or symptoms. Thus, you may not know you have it unless your doctor discovers it from a screening test or while checking for other problems.

Your doctor will do a physical exam to look for signs of iron-deficiency anemia. He or she may:

• Look at your skin, gums, and nail beds to see whether they’re pale
• Listen to your heart for rapid or irregular heartbeats
• Listen to your lungs for rapid or uneven breathing
• Feel your abdomen to check the size of your liver and spleen
• Do a pelvic and rectal exam to check for internal bleeding

Iron deficiency anemia tests

Your doctor will recommend blood tests to determine whether you have iron deficiency anemia, and possibly further tests to work out the cause.

• A complete blood count (CBC) and blood film show the hemoglobin level, plus the number and size of red blood cells. A low hemoglobin plus red blood cells that are smaller than normal and pale in color are features of iron-deficiency anemia.
• Iron studies (including iron, ferritin and transferrin) measure iron and iron stores in the body.

The complete blood count (CBC) measures many parts of your blood.

This test checks your hemoglobin and hematocrit levels. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen to the body. Hematocrit is a measure of how much space red blood cells take up in your blood. A low level of hemoglobin or hematocrit is a sign of anemia.

The normal range of these levels varies in certain racial and ethnic populations. Your doctor can explain your test results to you.

The complete blood count (CBC) also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal results may be a sign of infection, a blood disorder, or another condition.

Finally, the complete blood count (CBC) looks at mean corpuscular volume (MCV). MCV is a measure of the average size of your red blood cells. The results may be a clue as to the cause of your anemia. In iron-deficiency anemia, for example, red blood cells usually are smaller than normal.

Other tests may be needed to see if there is any bleeding in your stomach or bowel, or a condition which may be affecting the absorption of iron.

If the CBC results confirm you have anemia, you may need other blood tests to find out what’s causing the condition, how severe it is, and the best way to treat it.

Reticulocyte count. This test measures the number of reticulocytes in your blood. Reticulocytes are young, immature red blood cells. Over time, reticulocytes become mature red blood cells that carry oxygen throughout your body.

A reticulocyte count shows whether your bone marrow is making red blood cells at the correct rate.

Peripheral smear. For this test, a sample of your blood is examined under a microscope. If you have iron-deficiency anemia, your red blood cells will look smaller and paler than normal.

Tests to measure iron levels. These tests can show how much iron has been used from your body’s stored iron.

Tests to measure iron levels include:

• Serum iron. This test measures the amount of iron in your blood. The level of iron in your blood may be normal even if the total amount of iron in your body is low. For this reason, other iron tests also are done.
• Serum ferritin. Ferritin is a protein that helps store iron in your body. A measure of this protein helps your doctor find out how much of your body’s stored iron has been used.
• Transferrin level, or total iron-binding capacity. Transferrin is a protein that carries iron in your blood. Total iron-binding capacity measures how much of the transferrin in your blood isn’t carrying iron. If you have iron-deficiency anemia, you’ll have a high level of transferrin that has no iron.

Other tests. Your doctor also may recommend tests to check your hormone levels, especially your thyroid hormone. You also may have a blood test for a chemical called erythrocyte protoporphyrin. This chemical is a building block for hemoglobin.

Children also may be tested for the level of lead in their blood. Lead can make it hard for the body to produce hemoglobin.

Tests and Procedures for Gastrointestinal Blood Loss

Your doctor may refer you to a gastroenterologist (a specialist in conditions affecting the digestive tract) or surgeon, who may recommend an endoscopy and/or colonoscopy to investigate your digestive tract.

• Endoscopy. Doctors often check for bleeding from a hiatal hernia, an ulcer or the stomach with the aid of endoscopy. In this procedure, a thin, lighted tube equipped with a video camera is passed down your throat to your stomach. This allows your doctor to view the tube that runs from your mouth to your stomach (esophagus) and your stomach to look for sources of bleeding.
• Colonoscopy. To rule out lower intestinal sources of bleeding, your doctor may recommend a procedure called a colonoscopy. A thin, flexible tube equipped with a video camera is inserted into the rectum and guided to your colon. You’re usually sedated during this test. A colonoscopy allows your doctor to view inside some or all of your colon and rectum to look for internal bleeding.

Further investigation of women with heavy periods may involve an ultrasound of the pelvis to determine if there is an underlying cause, such as fibroids in the uterus (womb).

Iron deficiency anemia treatment

Treatment for iron deficiency anemia involves treating the underlying cause of your anemia and replacing iron with iron supplements and a good diet.

Severe iron-deficiency anemia may require a blood transfusion, iron injections, or intravenous (IV) iron therapy. Treatment may need to be done in a hospital.

The goals of treating iron-deficiency anemia are to treat its underlying cause and restore normal levels of red blood cells, hemoglobin, and iron.

Your blood count will be checked regularly to make sure the anemia has not returned.

Iron supplements

You may need iron supplements to build up your iron levels as quickly as possible. Iron supplements can correct low iron levels within months. Supplements come in pill form or in drops for children.

Large amounts of iron can be harmful, so take iron supplements only as your doctor prescribes. Keep iron supplements out of reach from children. This will prevent them from taking an overdose of iron.

Iron supplements are usually given as tablets, but if you need a high dose of iron, you may have an injection into a muscle or intravenous infusion (via a drip into a vein).

Intravenous iron therapy presents some safety concerns. It must be done in a hospital or clinic by experienced staff. Iron therapy usually is given to people who need iron long-term but can’t take iron supplements by mouth. This therapy also is given to people who need immediate treatment for iron-deficiency anemia.

Standard multivitamin tablets do not contain iron and, those that do, are usually labeled as multivitamins with iron. Iron for treatment of iron deficiency is available as various ferrous ion salts (gluconate, sulfate, fumarate), usually in concentrations of 200 to 400 mg per tablet, representing 30 to 100 mg of elemental iron. The typical recommended dose is 100 to 200 mg of elemental iron daily, which may represent 1 to 4 tablets (see Table 1) ⁸.

Table 1. Concentrations of elemental iron in typical iron tablets

Side effects of Iron tablets can include:

• dark or black bowel motions (this is harmless);
• indigestion;
• nausea;
• diarrhea; or
• constipation.

If side effects are troubling you, your doctor may change the tablets or suggest taking a smaller dose more frequently.

Take your tablets as prescribed and keep tablets out of the reach of children (an accidental overdose of iron tablets can be dangerous for children).

Taking your iron supplements

• Take iron tablets on an empty stomach (at least an hour before eating) to increase absorption. However, if you get bad indigestion you should take them with food.
• Don’t take iron supplements with milk, tea or coffee — these can reduce the amount of iron your body absorbs.
• Vitamin C helps with iron absorption – your doctor may recommend taking your tablets with orange juice.
• Wait 2 hours after taking iron tablets before taking other medicines. Some medicines and supplements – including antacids, medicines for gastro-esophageal reflux disease (GERD) and calcium supplements – can reduce iron absorption.
• Keep taking the tablets for at least 3 months or until your doctor tells you to stop. You should take them until well after your hemoglobin is normal.

If you are pregnant you may be given iron tablets. A healthy diet is also recommended.

Children with iron deficiency anemia should be given their iron medicine (usually in liquid form) before meals with orange juice (not milk), as vitamin C increases iron absorption. They should use a straw because liquid iron can discolor the mouth.

Iron deficiency anemia diet

Your doctor may advise you to eat more foods that are rich in iron. The best source of iron is red meat, especially beef and liver. Chicken, turkey, pork, fish, and shellfish also are good sources of iron.

The body tends to absorb iron from meat better than iron from nonmeat foods. However, some nonmeat foods also can help you raise your iron levels. Examples of nonmeat foods that are good sources of iron include:

Iron-fortified breads and cereals

• Peas; lentils; white, red, and baked beans; soybeans; and chickpeas
• Tofu
• Dried fruits, such as prunes, raisins, and apricots
• Spinach and other dark green leafy vegetables
• Prune juice

The Nutrition Facts labels on packaged foods will show how much iron the items contain. The amount is given as a percentage of the total amount of iron you need every day.

Vitamin C

Vitamin C helps the body absorb iron. Good sources of vitamin C are vegetables and fruits, especially citrus fruits. Citrus fruits include oranges, grapefruits, tangerines, and similar fruits. Fresh and frozen fruits, vegetables, and juices usually have more vitamin C than canned ones.

If you’re taking medicines, ask your doctor or pharmacist whether you can eat grapefruit or drink grapefruit juice. Grapefruit can affect the strength of a few medicines and how well they work.

Other fruits rich in vitamin C include kiwi fruit, strawberries, and cantaloupes.

Vegetables rich in vitamin C include broccoli, peppers, Brussels sprouts, tomatoes, cabbage, potatoes, and leafy green vegetables like turnip greens and spinach.

Iron-rich diet

Your body absorbs only a small amount of iron, so it is important to eat a lot of iron-rich foods (meat, fish or poultry, whole or enriched grains) every day. If you don’t eat meat (the best source of iron), make sure you eat plenty of leafy green vegetables, iron fortified foods (such as cereals), eggs, nuts, wholemeal bread and pasta, dried fruit, beans and lentils.

Eating a lot of foods rich in vitamin C (e.g. citrus fruits, kiwi fruit, red capsicum, leafy green vegetables) will help iron absorption.

Limit your milk intake to 500 mL daily in adults. Talk with your doctor, dietitian or community health nurse about other ways to get enough calcium.

Don’t drink tea with meals — it prevents iron absorption.

Your doctor or dietitian can tell you how much iron you need daily. A dietitian can plan a diet for you, and discuss iron intake for vegetarians.

What foods provide iron ?

Iron is found naturally in many foods and is added to some fortified food products. You can get recommended amounts of iron by eating a variety of foods, including the following:

• Lean meat, seafood, and poultry.
• Iron-fortified breakfast cereals and breads.
• White beans, lentils, spinach, kidney beans, and peas.
• Nuts and some dried fruits, such as raisins.

Iron in food comes in two forms: heme iron and nonheme iron. Nonheme iron is found in plant foods and iron-fortified food products. Meat, seafood, and poultry have both heme and nonheme iron.

Heme iron has higher bioavailability than nonheme iron, and other dietary components have less effect on the bioavailability of heme than nonheme iron ⁹. The bioavailability of iron is approximately 14% to 18% from mixed diets that include substantial amounts of meat, seafood, and vitamin C (ascorbic acid, which enhances the bioavailability of nonheme iron) and 5% to 12% from vegetarian diets ¹⁰. In addition to ascorbic acid, meat, poultry, and seafood can enhance nonheme iron absorption, whereas phytate (present in grains and beans) and certain polyphenols in some non-animal foods (such as cereals and legumes) have the opposite effect ¹¹. Unlike other inhibitors of iron absorption, calcium might reduce the bioavailability of both nonheme and heme iron. However, the effects of enhancers and inhibitors of iron absorption are attenuated by a typical mixed western diet, so they have little effect on most people’s iron status.

Several food sources of iron are listed in Table 2. Some plant-based foods that are good sources of iron, such as spinach, have low iron bioavailability because they contain iron-absorption inhibitors, such as polyphenols ¹².

Your body absorbs iron from plant sources better when you eat it with meat, poultry, seafood, and foods that contain vitamin C, like citrus fruits, strawberries, sweet peppers, tomatoes, and broccoli.

Table 2: Selected Food Sources of Iron

* DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration (FDA) to help consumers compare the nutrient contents of products within the context of a total diet. The DV for iron is 18 mg for adults and children age 4 and older. Foods providing 20% or more of the DV are considered to be high sources of a nutrient.

Other treatments

For severe iron deficiency anemia, you may need a blood transfusion.

• If you have heavy periods your doctor may be able to suggest medicines (such as the oral contraceptive pill) to reduce blood loss.
• Antibiotics and other medications to treat peptic ulcers
• Surgery to remove a bleeding polyp, a tumor or a fibroid

Prevention

The best way to prevent iron deficiency is to ensure your intake of iron is adequate, especially if you are at increased risk. See your doctor or a dietitian for advice on following an iron-rich diet.

Iron supplements may be recommended to prevent iron-deficiency anemia in people who are unable to get sufficient iron from food.

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