What Is Iron-Deficiency Anemia?
Anemia occurs when a person has lower-than-normal levels of red blood cells (RBCs) in the blood. According to the American Society of Hematology, there are many factors that can contribute to lower-than-normal RBC counts, including age, viral infections, and certain chronic diseases (ASH, 2010).
Iron-deficiency anemia is the most common type of anemia, which occurs when your body does not have enough of the mineral iron. Your body needs iron to produce a protein called hemoglobin, which is responsible for carrying oxygen to your body’s tissues. Your tissues and muscles need oxygen to function effectively.
In women of child-bearing age, the most common cause of iron-deficiency anemia is loss of iron in blood due to heavy menstruation or pregnancy. Iron-deficiency anemia can also be caused by a poor diet or by certain intestinal diseases that affect how the body absorbs iron. The condition is normally treated with iron supplements.
What Causes Iron-Deficiency Anemia?
According to the Centers for Disease Control and Prevention (CDC), iron deficiency is the most common nutritional deficiency in the United States. It is also the most common cause of anemia (CDC, 2011).
There are many reasons why a person might become deficient in iron. These include:
Inadequate Iron Intake
Eating too little iron over an extended amount of time can cause a shortage in your body. Iron can be found in foods such as meat, eggs, and some green vegetables. Pregnant women and young children may need even more iron in their diet, as it is essential during times of rapid growth and development.
Pregnancy or Blood Loss Due to Menstruation
In women of child-bearing age, the most common causes of iron-deficiency anemia are heavy menstrual bleeding or blood loss during childbirth. The CDC found that about nine percent of women ages 12 to 49 years are deficient in iron (CDC, 2012).
Certain medical conditions can cause internal bleeding, which can lead to iron-deficient anemia. Examples include an ulcer in your stomach, polyps (tissue growths) in the colon or intestines, or colon cancer. Regular use of pain relievers, such as aspirin, can also cause bleeding in the stomach.
Inability to Absorb Iron
Certain disorders or surgeries that affect the intestines can also interfere with how your body absorbs iron. Even if you get enough iron in your diet, Celiac disease or an intestinal surgery such as gastric bypass may limit the amount of iron your body can absorb.
Who Is at Risk for Iron-Deficiency Anemia?
Anemia is a common condition and can occur in both men and women, in all ages and ethnic groups. The risk for iron-deficiency anemia is higher in the following groups:
- women of child-bearing age
- pregnant women
- people with poor diets
- frequent blood donors
- infants and children, especially those born prematurely or experiencing a growth spurt
- vegetarians who do not replace meat with another iron-rich food
What Are the Symptoms of Iron-Deficiency Anemia?
Symptoms of iron-deficiency anemia can be very mild at first, and may go completely unnoticed. In fact, most people do not realize they have mild anemia until it is identified in a routine blood test (ASH, 2010).
Symptoms of moderate to severe iron-deficiency anemia include:
- general fatigue
- pale skin
- shortness of breath
- strange cravings for non-food items, such as dirt, ice, and clay
- tingling or a crawling feeling in the legs
- swelling or soreness in the tongue
- cold hands and feet
- fast or irregular heartbeat
- brittle nails
How Is Iron-Deficiency Anemia Diagnosed?
A doctor can diagnose anemia with blood tests. These include:
Complete Blood Cell (CBC) Test
A test called a complete blood cell (CBC) test is usually the first test a doctor will use. A CBC test measures the amount of all components in the blood, including:
- white blood cells (WBCs)
The CBC test provides information about your blood that is helpful in diagnosing iron-deficiency anemia. This information includes:
- hematocrit levels (percent of blood volume that is made up by RBCs)
- hemoglobin levels
- size of your RBCs
In iron-deficiency anemia, hematocrit and hemoglobin levels are low. RBCs are usually smaller in size than normal.
A CBC test is often performed as part of a routine physical examination. It is a good indicator of a person’s overall health. It may also be performed routinely before a surgery. This test is useful to diagnose this type of anemia since most people do not realize they are iron-deficient.
Anemia can usually be confirmed with a CBC test. Your doctor might order additional blood tests to determine the severity of your anemia and how to treat it. They may also examine your blood by using a microscope. These tests will provide information including:
- RBC size and color (RBCs are pale in color if they are deficient in iron)
- ferritin levels (this protein helps with iron storage in your body. Low levels indicate low iron storage)
- iron level in your blood
- total iron-binding capacity: a test to determine the amount of a protein, named transferrin, that is carrying iron.
Tests for Internal Bleeding
A doctor might also perform additional diagnostic tests to rule out internal bleeding from other parts of the body. Examples include:
- fecal occult test to look for blood in the feces. Blood in the feces may indicate bleeding in the intestine.
- pelvic ultrasound to look for an underlying source of excess bleeding during a woman’s period, such as fibroids (non-cancerous tumors in the uterus)
What Are the Potential Health Complications of Iron-Deficiency Anemia?
Most cases of iron-deficiency anemia are mild and do not cause complications. However, if anemia or iron deficiency is not treated, it can lead to other health problems, including:
Rapid or Irregular Heartbeat
When you are anemic, your heart must pump more blood to compensate for the low amount of oxygen. This can lead to irregular heartbeat, or in severe cases, heart failure or an enlarged heart may occur.
In severe cases of iron deficiency, a child may be born prematurely or with a low birth weight. Most pregnant women take iron supplements as part of their prenatal care to prevent this from happening.
Delayed Growth in Infants and Children
Infants and children who are severely deficient in iron may experience a delay in their growth and development. They may also be more susceptible to infections.
How Is Iron-Deficiency Anemia Treated?
Iron tablets can help restore iron levels in your body. If possible, you should take the iron tablets on an empty stomach to improve absorption. If they upset your stomach, they can be taken with meals. You may need to take the supplements for several months. Iron supplements may cause constipation or stools that are black in color.
Diets high in red meat, dark leafy vegetables, dried fruits and nuts, and iron-fortified cereals can help treat or prevent iron deficiency. Additionally, vitamin C helps your body absorb iron. If you are taking iron tablets, a doctor might suggest taking the tablets along with a source of vitamin C, like a glass of orange juice or citrus fruit.
Treating the Underlying Cause of Bleeding
Iron supplements will not help if the deficiency is caused by excess bleeding. Oral contraceptives (birth control pills) might be prescribed to women who experience heavy periods to reduce the amount of menstrual bleeding each month.
In the most severe cases, a blood transfusion can replace iron and blood loss quickly.
Can Iron-Deficiency Anemia Be Prevented?
When caused by inadequate iron intake, iron-deficiency anemia can be prevented by eating a diet high in iron-rich foods and vitamin C. Mothers should make sure to feed their babies breast milk or iron-fortified infant formula.
Foods high in iron include:
- meat, such as lamb, pork, chicken, and beef
- pumpkin and squash seeds
- leafy greens, such as spinach
- raisins and other dried fruit
- seafood, such as clams, sardines, shrimp, and oysters
- iron-fortified dry and instant cereals
Foods high in vitamin C include:
- citrus fruits, such as oranges, grapefruit, strawberries, kiwis, guava, papaya, pineapple, melons, and mango
- red and green bell peppers
- Brussels sprouts
- leafy greens