Iron-Deficiency Anemia

About Iron-Deficiency Anemia

The body needs iron to make hemoglobin. If there isn't enough iron available, hemoglobin production is limited, which in turns affects the production of red blood cells (RBCs). A decreased amount of hemoglobin and RBCs in the bloodstream is known as anemia. Because RBCs are needed to carry oxygen throughout the body, anemia results in less oxygen reaching the cells and tissues, affecting their function.

Iron-deficiency anemia (IDA), often caused by insufficient iron intake, is the major cause of anemia in childhood. It has become much less common in the United States over the past 30 years, primarily due to iron-fortified infant formulas and cereals.

Iron-deficiency anemia doesn't develop immediately. Instead, a person progresses through stages of iron deficiency, beginning with iron depletion, in which the amount of iron in the body is reduced while the iron in RBCs remains constant. If iron depletion isn't corrected, it progresses to iron deficiency, eventually leading to IDA.

Causes of IDA

Iron-deficiency anemia can be the consequence of several factors, including:

• insufficient iron in the diet
• poor absorption of iron by the body
• ongoing blood loss, most commonly from menstruation or from gradual blood loss in the intestinal tract
• periods of rapid growth

A diet low in iron is most often behind IDA in infants, toddlers, and teens. Kids who don't eat enough or who eat foods that are poor sources of iron are at risk for developing the condition. Poverty is a contributing factor to IDA because families living at or below the poverty level may not be getting enough iron-rich foods.

Iron deficiency can also cause the body to absorb more lead, which increases the risk of lead poisoning in kids, especially those living in older homes. The combination of IDA and lead poisoning can make kids very ill and can put them at risk for learning and behavioral problems.

During infancy and adolescence, the body demands more iron. Kids are at higher risk for IDA through these periods of rapid growth because they may not be getting enough iron in their diet to make up for the increased needs.

In infants, discontinuing iron-fortified formula and introducing cow's milk before 12 months can lead to IDA. Cow's milk is low in the iron necessary for infant growth and development and it often replaces the consumption of iron-rich foods. Milk decreases the absorption of iron and can also irritate the lining of the intestine, causing small amounts of bleeding. This slow, gradual loss of blood in the stool — combined with low iron intake — may eventually result in iron deficiency and anemia.

More Risks By Age

Prematurity and low birth weight are other factors that put an infant at risk for IDA. Before birth, full-term, normal-weight babies have developed iron stores that can last them 4 to 6 months. Because preemies don't spend as much time in the uterus getting nutrients from the mother's diet, their iron stores are not as great and are often depleted in just 2 months.

Kids between 1 and 3 years old are at risk of iron deficiency and iron-deficiency anemia, even though it isn't a period of exceptional growth. Most toddlers are no longer consuming iron-fortified formula and infant cereal, and they aren't eating enough iron-rich foods to make up the difference. Toddlers also tend to drink a lot of cow's milk, often more than 24 ounces a day, an amount that injures the lining of the stomach causing chronic blood loss leading to iron deficiency.

During the first stages of puberty, when a lot of growth occurs, boys are at risk of iron deficiency anemia. But adolescent girls are at higher risk than boys for IDA because of smaller iron stores and the iron lost in the blood in their monthly menstrual flow. Many girls also tend to consume a diet low in iron.

Symptoms

Many kids with iron deficiency don't show any symptoms because the body's iron stores are depleted slowly. As the anemia progresses, you may recognize some of the following symptoms in your child:

• fatigue and weakness
• pale skin and mucous membranes
• rapid heartbeat or a new heart murmur (detected in an exam by your child's doctor)
• irritability
• decreased appetite
• dizziness or a feeling of being lightheaded

Rarely, a person with IDA may experience pica, a craving to eat nonfood items such as paint chips, chalk, or dirt. Pica may be caused by a lack of iron in the diet.

Diagnosis

Iron-deficiency anemia is often first noticed during a routine exam. Because IDA symptoms, such as fatigue and decreased appetite, are common to many conditions, the doctor will need more information to make a diagnosis. If IDA is suspected, the doctor will probably ask questions about your family's diet.

To diagnose iron deficiency, one of these blood tests will probably be done:

• A complete blood count (CBC) may reveal low hemoglobin levels and low hematocrit (the percentage of the blood made up of RBCs). The CBC also gives information about the size of the RBCs; those with low hemoglobin tend to be smaller and each cell contains less hemoglobin.
• The reticulocyte count measures how fast these immature RBCs are produced. In IDA, they're made too slowly in the bone marrow to reach a normal level.
• Serum iron directly measures the amount of iron in the blood, but may not accurately reflect how much iron is concentrated in the body's cells.
• Serum ferritin reflects total body iron stores. It's one of the earliest indicators of depleted iron levels, especially when used in conjunction with other tests, such as a CBC.

The doctor may also do a stool test because IDA can be caused by gradual loss of small amounts of blood through the gastrointestinal tract. Since the blood may not be visible, a stool sample is placed on a special paper card and a drop of testing solution is applied. A color change indicates the presence of blood.

Treating Iron Deficiency Anemia

Even though most cases of IDA are the result of poor dietary iron intake, diet changes alone usually aren't enough to replenish depleted iron stores. Likewise, multivitamins with iron aren't adequate for kids with IDA who have such low iron stores, so a separate daily iron supplement may be required.

It's extremely important to remember that your child should not be given potent iron supplements without first consulting a doctor. Taking too much iron is a major cause of serious poisoning in children, according to the American Academy of Pediatrics (AAP).

Iron is best absorbed on an empty stomach, because it can occasionally cause stomach upset. Kids who experience stomach problems when taking iron supplements may need to take them with a small amount of food. Iron should not, however, be given with milk or caffeinated beverages, which will interfere with absorption. Vitamin C enhances iron absorption, so try to include plenty of sources of vitamin C in your child's diet.

After the first month on iron supplements, your doctor may want to repeat the blood tests to check that hemoglobin and hematocrit levels are improving. If there's a good response, the doctor will probably continue the iron supplement for several more months. Once corrected, iron stores can be maintained with an iron-rich diet. About 6 months after discontinuing iron therapy, the doctor may want to recheck your child's hemoglobin.

Rarely, IDA is so severe and possibly life-threatening that hospitalization and a blood transfusion may be required.

Caring for Your Child

The effects of IDA will depend on the duration and severity of the anemia. If left untreated, it may lead to behavioral or learning problems. These may not be reversible, even with later iron supplementation.

But in most cases, IDA is preventable by following some basic recommendations:

• Infants younger than 1 year old should drink only breast milk or an infant formula supplemented with iron. It is important for breastfed infants to receive iron-fortified solid foods starting at about 6 months of age.
• Kids under 2 years old should have no more than 24 ounces of cow's milk a day. As noted earlier, milk can inhibit absorption of iron, and drinking too much milk can dampen a child's appetite for other iron-rich foods. In addition, too much cow's milk has been shown to irritate the gastrointestinal tract, which may cause intestinal bleeding — a cause of iron loss.
• Iron-fortified products such as cereal can be a great way to get kids — especially those under 2 years old — to get more iron.
• A variety of foods can provide great sources of iron: lean meats; egg yolks; broccoli, spinach, and other green leafy vegetables; dried peas and beans; blackstrap molasses; raisins; and whole-grain bread.
• Make sure kids or teens on a vegetarian diet get enough iron. Because iron from meat sources is more easily absorbed than iron from plant sources, you may need to add iron-fortified foods to their diet.

Proper nutrition, which includes a diet rich in iron, is important for all kids. Establishing good eating habits early in life will help to prevent iron deficiency and iron-deficiency anemia.

Reviewed by: Christopher N. Frantz, MD
Date reviewed: October 2010