Iron is very important in maintaining many body
functions, including the production of hemoglobin, the molecule in your
blood that carries oxygen. Iron is also necessary to maintain healthy
cells, skin, hair, and nails.
Iron from the food you eat is absorbed into the body
by the cells that line the gastrointestinal tract; the body only
absorbs a small fraction of the iron you ingest. The iron is then
released into the blood stream, where a protein called transferrin attaches
to it and delivers the iron to the liver. Iron is stored in the liver
as ferritin and released as needed to make new red blood cells in the
bone marrow. When red blood cells are no longer able to function (after
about 120 days in circulation), they are re-absorbed by the spleen.
Iron from these old cells can also be recycled by the body.
Am I at Risk?
Iron deficiency is very common, especially among women
and in people who have a diet that is low in iron. The following
groups of people are at highest risk for iron-deficiency anemia:
- Women who menstruate, particularly if menstrual
periods are heavy
- Women who are pregnant or breastfeeding or those who have recently given birth
- People who have undergone major surgery or physical
trauma
- People with gastrointestinal diseases such as
celiac disease (sprue), inflammatory bowel diseases such as ulcerative
colitis, or Crohn disease
- People with peptic ulcer disease
- People who have undergone bariatric procedures,
especially gastric bypass operations
- Vegetarians, vegans, and other people whose diets
do not include iron-rich foods (Iron from vegetables, even those that
are iron-rich, is not absorbed as well as iron from meat, poultry, and
fish.)
- Children who drink more than 16 to 24 ounces a day
of cow’s milk (Cow’s milk not only contains little iron, but it can
also decrease absorption of iron and irritate the intestinal lining
causing chronic blood loss.)
Other less common causes of iron deficiency include:
- Blood loss from the gastrointestinal tract due to
gastritis (inflammation of the stomach), esophagitis (inflammation of
the esophagus), ulcers in the stomach or bowel, hemorrhoids,
angiodysplasia (leaky blood vessels similar to varicose veins in the
gastrointestinal tract), infections such as diverticulitis, or tumors
in the esophagus, stomach, small bowel, or colon
- Blood loss from chronic nosebleeds
- Blood loss from the kidneys or bladder
- Frequent blood donations
- Intravascular hemolysis, a condition in which red
blood cells break down in the blood stream, releasing iron that is then
lost in the urine. This sometimes occurs in people who engage in
vigorous exercise, particularly jogging. This can cause trauma to small
blood vessels in the feet, so called “march hematuria.” Intravascular
hemolysis can also be seen in other conditions including damaged heart
valves or rare disorders such as thrombotic thrombocytopenia purpura
(TTP) or diffuse intravascular hemolysis (DIC).
What Are the Signs and Symptoms of Iron-Deficiency
Anemia?
Symptoms of iron-deficiency anemia are related to
decreased oxygen delivery to the entire body and may include:
- Being pale or having yellow “sallow” skin
- Unexplained fatigue or lack of energy
- Shortness of breath or chest pain, especially
with activity
- Unexplained generalized weakness
- Rapid heartbeat
- Pounding or “whooshing” in the ears
- Headache, especially with activity
- Craving for ice or clay – “picophagia”
- Sore or smooth tongue
- Brittle nails or hair loss
How Is Iron-Deficiency Anemia Diagnosed?
Iron-deficiency anemia is diagnosed by blood tests that should
include a complete
blood count (CBC). Additional tests may be ordered to evaluate the
levels of serum ferritin, iron, total iron-binding capacity, and/or
transferrin. In an individual who is anemic from iron deficiency, these
tests usually show the following results:
The peripheral smear or blood slide may show small,
oval-shaped cells with pale centers. In severe iron deficiency, the white
blood count (WBC) may be low and the platelet
count may be high or low.
What Other Tests Will Be Done If Iron Deficiency Is Diagnosed?
Your doctor will decide if other tests are necessary. Iron
deficiency is common in menstruating and pregnant women, children, and
others with a diet history of excessive cow’s milk or low
iron-containing foods. By talking with your doctor about your diet and
medical history, your doctor may gain enough information to determine
whether additional testing is needed. In patients such as men,
postmenopausal women, or younger women with severe anemia, the doctor
may recommend additional testing. These tests may include the
following:
- Testing for blood in the stool (fecal
occult blood test)
- Looking for abnormalities in the gastrointestinal tract –
upper and lower endoscopy (looking into the stomach, esophagus, or
colon with a tube), capsule enteroscopy (swallowing a tiny camera that
takes images of the gastrointestinal tract), barium enema, barium
swallow, or small bowel biopsy
- Testing the urine for blood or hemoglobin
- In women with abnormal or increased menstrual blood losses, a
gynecologic evaluation that may include a pelvic ultrasound or uterine
biopsy
Sometimes it is difficult to diagnose the cause of iron
deficiency, or your doctor may be concerned that there is a problem
other than iron deficiency causing the anemia. These may include
inherited blood disorders called thalassemiasin which
red blood cells also appear small and pale, hemoglobinopathies such as
sickle cell disease (but not sickle cell trait alone), or other blood
disorders. People with chronic infections or conditions such as kidney
failure, autoimmune diseases, and inflammatory disorders may also have
small red blood cells. When the cause of the anemia is not clear, your
doctor may refer you to a hematologist, a medical specialist in blood
disorders,for consultation and further evaluation.
How Is Iron Deficiency Treated?
Even if the cause of the iron deficiency can be identified and
treated, it is still usually necessary to take medicinal iron (more
iron than a multivitamin can provide) until the deficiency is corrected
and the body’s iron stores are replenished. In some cases, if the
cause cannot be identified or corrected, the patient may have to
receive supplemental iron on an ongoing basis.
There are several ways to increase iron intake:
Diet
- Meat: beef, pork, or lamb, especially organ meats such as
liver
- Poultry: chicken, turkey, and duck, especially liver and
dark meat
- Fish, especially shellfish, sardines, and anchovies
- Leafy green members of the cabbage family including
broccoli, kale, turnip greens, and collard greens
- Legumes, including lima beans, peas, pinto beans, and
black-eyed peas
- Iron-enriched pastas, grains, rice, and cereals
Medicinal Iron
The amount of iron needed to treat patients with iron
deficiency is higher than the amount found in most daily multivitamin
supplements. The amount of iron prescribed by your doctor will be in
milligrams (mg) of elemental iron. Most people with iron deficiency
need 150-200 mg per day of elemental iron (2 to 5 mg of iron per
kilogram of body weight per day). Ask your doctor how many milligrams
of iron you should be taking per day. If you take vitamins, bring them
to your doctor’s visit to be sure.
There is no evidence that any one type of iron salt, liquid, or
pill is better than the others, and the amount of elemental iron
varies with different preparations. To be sure of the amount of iron in
a product, check the packaging. In addition to elemental iron, the
iron salt content (ferrous sulfate, fumarate, or gluconate) may also be
listed on the package, which can make it confusing for consumers to
know how many tablets or how much liquid to take to get the proper
dosage of iron.
Iron is absorbed in the small intestine (duodenum and first
part of the jejunum). This means that enteric-coated iron tablets may
not work as well. If you take antacids, you should take iron tablets
two hours before or four hours after the antacid. Vitamin C (ascorbic
acid) improves iron absorption, and some doctors recommend that you
take 250 mg of vitamin C with iron tablets.
Possible side effects of iron tablets include abdominal
discomfort, nausea, vomiting, diarrhea, constipation, and dark stools.
Intravenous Iron
In some cases your doctor may recommend intravenous (IV) iron.
IV iron may be necessary to treat iron deficiency in patients who do
not absorb iron well in the gastrointestinal tract, patients with
severe iron deficiency or chronic blood loss, patients who are
receiving supplemental erythropoietin, a hormone that stimulates blood
production, or patients who cannot tolerate oral iron. If you need IV
iron, your doctor may refer you to a hematologist to supervise the iron
infusions. IV iron comes in different preparations:
- Iron dextran
- Iron sucrose
- Ferric gluconate
Large doses of iron can be given at one time when using iron
dextran. Iron sucrose and ferric gluconate require more frequent doses
spread over several weeks. Some patients may have an allergic reaction
to IV iron, so a test dose may be administered before the first
infusion. Allergic reactions are more common with iron dextran and may
necessitate switching to a different preparation. Severe side effects
other than allergic reactions are rare and include urticaria (hives),
pruritus (itching), and muscle and joint pain.
Blood Transfusions
Red blood cell transfusions may be given to patients with severe
iron-deficiency anemia who are actively bleeding or have significant
symptoms such as chest pain, shortness of breath, or weakness.
Transfusions are given to replace deficient red blood cells and will
not completely correct the iron deficiency. Red blood cell transfusions
will only provide temporary improvement. It is important to find out
why you are anemic and treat the cause as well as the symptoms.
Where Can I Find More Information?
If you find that you are interested in
learning more about blood diseases and disorders, here are a few other
resources that may be of some help:
Articles
From Hematology, the ASH Education Program Book
The American Society of Hematology (ASH) Education Book, updated
yearly by experts in the field, is a collection of articles about the
current treatment options available to patients. The articles are
categorized here by disease type. If you are interested in learning
more about a particular blood disease, we encourage you to share and
discuss these articles with your doctor.
Results of
Clinical Studies Published in Blood
Search Blood, the official journal of ASH, for the
results of the latest blood research. While recent articles generally
require a subscriber login, patients interested in viewing an
access-controlled article in Blood may obtain a copy by
e-mailing a request to the Blood
Publishing Office.
Other
Resources
This section includes a list of Web links to patient groups and
other organizations that provide information.
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