Multiple: Iron-Deficiency Anemia
Multiple: Iron-Deficiency Anemia
Anemia is a condition in which the blood does not have enough hemoglobin in its red cells. It is a sign of a disease process of some kind rather than a disease by itself. Anemia is the most common blood disorder in the general population. There are many different types of anemias. Some result from blood loss, some from overly rapid destruction of red blood cells (RBCs), and some from the body's failure to produce enough RBCs.
Iron-deficiency anemia is the most common form of anemia. It occurs when people do not get enough iron in their diets, when their bodies do not absorb enough iron from the diet, or when blood loss occurs. Iron is needed for the production of hemoglobin, a substance found in red blood cells that carries oxygen from the lungs to other parts of the body. When there is not enough hemoglobin in the blood, the body's tissues and organs become oxygen-starved, leading to tiredness, loss of a healthy color in the skin, headaches, and other symptoms.
Iron-deficiency anemia varies in severity from person to person. Some people may not have any symptoms—particularly if the loss of iron happens gradually over a long period of time—and may be diagnosed in the course of a routine blood test. Others may tire easily, feel weak, lose weight, or have frequent headaches. Young children and pregnant women can develop serious health problems as a result of iron-deficiency anemia. Children with anemia may develop heart murmurs or experience delays in growth and development. Pregnant women with iron-deficiency anemia have a higher risk of giving birth prematurely or having babies with low birth weight.
Another health problem that can arise as a result of iron-deficiency anemia is a rapid or irregular heartbeat. When the blood is not carrying enough oxygen to meet the needs of the body, the heart will speed up in order to pump more blood to the tissues. Over time, the increased workload on the heart can lead to enlargement of the heart, chest pain, and even heart failure.
The exact number of people in the United States with iron-deficiency anemia is not known. One estimate is 3.4 million adults and children; however, many researchers think that this figure is much too low. Iron-deficiency anemia in developed countries is most common in women of childbearing age because women lose more iron than men through menstruation and pregnancy. Whereas a healthy male loses about 1 milligram of iron each day, mostly through the digestive tract, women lose between 4 and 100 milligrams of iron with each menstrual period and 500 milligrams of iron with each pregnancy. Most women need to absorb twice as much iron from their diet as men.
In developing countries, iron-deficiency anemia is six to eight times more common than in North America and Europe. One reason for the difference is that people in these countries eat less meat. It is easier for the body to absorb the iron it needs from meat than from vegetables. A second reason is that intestinal parasites—particularly hookworms—are relatively common in developing countries. Intestinal parasites can lead to iron-deficiency anemia because they cause the infected person to lose blood through the digestive tract.
Risk factors for iron-deficiency anemia include:
- Sex. Twenty percent of women of child-bearing age have iron-deficiency anemia compared to 2 percent of men.
- Age. Infants or children who are not getting enough iron in their diet are at risk, particularly those who are given cow's milk rather than being breastfed and older children going through rapid growth spurts. Elderly people are also at increased risk of anemia because aging reduces the ability to taste food, leading to loss of appetite and possible malnutrition.
- Premature or low-birth-weight babies.
- Eating a strict vegetarian diet.
- Undiagnosed peptic ulcers, colon cancer, or other diseases that can cause loss of blood through the digestive tract.
- Kidney disorders that must be treated with dialysis. The process of dialysis shortens the life span of red blood cells.
Iron-deficiency anemia can be caused by a lack of iron in the diet, by the body's inability to absorb iron, or by the loss of blood through the digestive tract, menstruation, or pregnancy. People's diets may not contain enough iron because they are malnourished in general or because they do not eat meat, fish, or dairy products. Diseases that affect the small intestine, such as celiac disease or Crohn's disease, are the most common cause of failure to absorb iron, because the small intestine is the part of the digestive system where iron is taken into the bloodstream from partially digested food. Blood loss through the digestive tract may have several causes, ranging from colorectal cancer or peptic ulcers to intestinal parasites or long-term use of aspirin.
When the Doctor Recommends Iron Pills
Iron supplements can cause heartburn, constipation, or stomach cramps. To lower the risk of these side effects, people who are taking iron tablets or capsules as treatment for iron-deficiency anemia may want to try the following tips:
- Take the pills or capsules with food.
- Do not take the iron supplement at bedtime if it causes stomach upset.
- Add foods rich in fiber to the diet or take a stool softener if constipation is a problem.
- Start with a low dose of the iron supplement—perhaps just one pill or capsule per day—and work up gradually to the full dose recommended by the doctor.
- If one type of iron formula causes problems, talk to the doctor about a different formula. Some people find that iron in capsule form is easier on their digestion than pills.
People with mild anemia may not have any symptoms. The most common symptoms that appear in persons with moderate
iron-deficiency anemia are tiring easily, pale skin, weakness, shortness of breath, headache, lightheadedness, and cold hands or feet. Less common symptoms include:
- Loss of appetite and unintended weight loss
- Sore tongue
- Brittle fingernails
- Unusual cravings for ice, starch, dirt, or other substances that are not food (a condition called pica)
- Bloody or tarry-looking stools
Iron-deficiency anemia is often diagnosed as the result of a routine blood test during blood donation or a yearly medical checkup. The blood test may reveal either that there is a low level of hemoglobin in the person's blood cells or that the blood has a low hematocrit (a measurement of the ratio of red blood cells to liquid serum in the person's blood). Normal hemoglobin levels for the general population are between 12 and 16 grams per deciliter (g/dL) of blood. A normal hematocrit level is between 36 and 46 percent for women and 46 to 56 percent for men. A patient who has a hemoglobin level below 12 g/dL or a hematocrit below 36 in women or 46 in men will be diagnosed as having iron-deficiency anemia.
Other measurements that may be taken from a blood sample are the amount of iron itself in the blood serum; the amount of ferritin, a protein that helps the body store iron; and the level of transferrin, a protein that carries iron in the blood. A low level of ferritin and a high level of transferrin point to a diagnosis of iron-deficiency anemia.
A colonoscopy or an ultrasound study may be ordered if the doctor suspects that the patient's anemia is caused by blood loss through the digestive system.
The usual treatment for iron-deficiency anemia caused by an iron-poor diet is a combination of adding iron-rich foods to the patient's diet plus dietary supplements containing iron. Red meat, especially beef and liver, is the best source of iron in the diet. Other iron-rich foods include chicken, turkey, pork, fish, and shellfish; eggs; pasta or cereals that are fortified with iron; beans and nuts; dried fruits; and green leafy vegetables
like spinach. The doctor may also recommend adding citrus fruits and other fruits and vegetables rich in vitamin C (mangos, apricots, strawberries, cantaloupe, watermelon, broccoli, tomatoes, peppers, cabbage, and potatoes) to the daily menu. Vitamin C helps the body absorb the iron that is present in meat and other foods.
Dietary supplements may include multivitamins containing iron and vitamin C, or iron compounds in pill or capsule form to be taken with meals. Because iron supplements can cause constipation or heartburn, patients may need to make some adjustments at mealtimes (see sidebar).
Patients whose anemia is caused by intestinal parasites will be given medications to kill the parasites. Those with colorectal cancer or other disorders of the small intestine are usually treated with surgery. Peptic ulcers are treated with a combination of antibiotics and Pepto-Bismol or drugs that block the production of stomach acid.
Patients with severe anemia may require hospital treatment, including blood transfusions and iron injections.
Iron-deficiency anemia is easily treated and has an excellent prognosis when the patient's only problem is lack of iron in the diet. Most people's hematocrit will return to normal after two months of iron therapy. Iron supplements should be continued for another six to twelve months, however, to build up the body'sreservesofironinthe bone marrow. In general, older adults take longer to regain normal hemoglobin and hematocrit levels than younger people. The patients with the poorest prognosis are those whose anemia is caused by colorectal cancer.
Iron-deficiency anemia can usually be prevented simply by eating a well-balanced diet that includes iron-rich foods and foods containing vitamin C. Other preventive measures include:
- Taking iron supplements if following a vegetarian diet.
- Avoiding extreme weight-reduction diets or food fads.
- Breastfeeding a baby for the first year of life rather than giving cow's milk.
- Women who are pregnant or menstruate heavily should check with their doctor about the possible need for iron supplements as well as eating an iron-rich diet.
- Older adults should also have periodic blood tests, particularly if they take high doses of aspirin or other over-the-counter pain relievers for arthritis, or if they are losing their appetite for food.
Iron-deficiency anemia is likely to continue to be a common health problem in all age groups in the United States because it has so many different potential causes, ranging from poor diet to stomach and intestinal disorders. Researchers are presently trying to develop simpler tests for diagnosing the causes of iron-deficiency anemia. They are studying the safety of a newer iron-containing formula that would be easier to digest than current pills and capsules.
SEE ALSO Celiac disease; Colorectal cancer; Crohn disease; Heart failure; Lead poisoning; Prematurity; Restless legs syndrome; Sickle cell anemia; Thalassemia; Ulcers
WORDS TO KNOW
Anemia : A condition in which a person's blood does not have enough volume, enough red blood cells, or enough hemoglobin in the cells to keep body tissues supplied with oxygen.
Hematocrit : The proportion of blood volume occupied by red blood cells.
Hemoglobin : An iron-containing protein in red blood cells that carries oxygen from the lungs to the rest of the body.
Pica : An abnormal craving for substances that are not normally considered food, like soil, chalk, paper, or ice cubes.
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