Iron
What does it do?
Iron is part of hemoglobin, the oxygen-carrying component of the blood.
Iron-deficient people tire easily because their bodies are starved for
oxygen. Iron is also part of myoglobin, which helps muscle cells store
oxygen. Without enough iron, ATP (the fuel the body runs on) cannot be
properly synthesized. As a result, some iron-deficient
people become fatigued even when their hemoglobin levels are normal.
Although iron is part of
the antioxidant enzyme catalase, iron is not generally considered an
antioxidant, because too much iron can cause oxidative damage.
Where is it found?
The most absorbable form of iron, called “heme” iron, is found in oysters,
meat, poultry, and fish. Non-heme iron is also found in these foods, as
well as in dried fruit, molasses, leafy green vegetables, wine, and most
iron supplements. Acidic foods (such as tomato sauce) cooked in an iron
pan can also be a source of dietary iron.
Who is
likely to be deficient? Vegetarians
eat less iron than nonvegetarians, and the iron they eat is somewhat less
absorbable. As a result, vegetarians are more likely to have reduced iron
stores.
However, iron deficiency is not usually caused by a lack of iron in the
diet alone; an underlying cause, such as iron loss in menstrual blood,
often exists.
Pregnant women, marathon
runners, people who take aspirin,
and those who have parasitic
infections, hemorrhoids, ulcers, ulcerative
colitis, Crohn’s
disease, gastrointestinal cancers, or other conditions that cause
blood loss or malabsorption are likely to become deficient.
Individuals who fit into
one of these groups, even pregnant women, shouldn’t automatically take
iron supplements. Fatigue, the first symptom of iron deficiency, can be
caused by many other things. A nutritionally oriented doctor should assess
the need for iron supplements, since taking iron when it isn’t needed does
no good and may do some harm.
How much is usually
taken? If a nutritionally oriented doctor diagnoses iron
deficiency, iron supplementation is essential. A common adult dose is
100 mg per day. When iron deficiency is diagnosed, the doctor must also
determine the cause. Usually it’s not serious (such as normal menstrual
blood loss or blood donation). Occasionally, however, iron deficiency
signals ulcers or even colon cancer.
Many
premenopausal women become marginally iron deficient unless they
supplement with iron. Even so, the 18 mg of iron present in most
multiple-vitamin/mineral supplements is often adequate.
Are there any side effects or interactions?
Huge overdoses
(as when a child swallows an entire bottle of iron supplements) can be
fatal. Keep iron-containing supplements out of a child’s reach.
Hemochromatosis, hemosiderosis, polycythemia, and iron-loading anemias
(such as thalassemia and sickle cell anemia) are conditions involving
excessive storage of iron. Supplementing iron can be quite dangerous for
people with these diseases.
Supplemental amounts
required to overcome iron deficiency can cause constipation.
Sometimes switching the form of iron, getting more exercise, or treating
the constipation with fiber and
fluids is helpful. Sometimes the amount of iron must be reduced if
constipation occurs.
Some researchers have
linked excess iron to diabetes, cancer, increased risk of
infection,4
systemic
lupus erythematosus (SLE), exacerbation of
rheumatoid
arthritis,
and heart disease,
though a review of the best studies has found no link.10 None of these links has been
proven. Nonetheless, too much iron causes free
radical damage, which can cause or exacerbate most of these diseases.
People who are not iron deficient should not supplement iron when
potential risks might exist and no benefit can be found.
Caffeine,
high-fiber
foods, and calcium
supplements reduce iron absorption. Vitamin
C slightly increases iron absorption. Taking vitamin
A with iron helps treat iron deficiency, since vitamin A helps the
body use iron stored in the liver.
Deferoxamine
is a drug that binds to some metals, including iron, and carries them out
of the body. It is used to treat acute iron poisoning, chronic iron
overload, and aluminum accumulation in people with kidney failure. People
taking deferoxamine to treat iron overload must not take iron supplements,
including the amounts found in many multivitamin/minerals.
Penicillamine
binds metals (including copper and iron) and carries them out of the body.
When penicillamine and iron are taken together, penicillamine absorption
and activity are reduced. Four cases of penicillamine-induced kidney
damage were reported when concomitant iron therapy was stopped, which
presumably led to increased penicillamine absorption and
toxicity.
