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|
| Proper name |
Iron |
| Category |
Mineral |
| Functions |
The most important function of iron is to carry oxygen. The heme form of
iron combines with globulin protein to form hemoglobin. Heme is composed
of 4 atoms of iron. This is the form of iron in red blood cells needed to
carry oxygen to the tissues. Myoglobin is similar to hemoglobin and acts
as the oxygen acceptor in muscle cells. Myoglobin also allows oxygen to
be stored in the muscles. Iron is used in the synthesis of the amino acid
carnatine, an important component of muscle tissue, especially the heart.
Iron is needed to synthesize elastin and collagen. Iron is required
in the cytochrome P-450 liver detoxification enzymes, in the oxidation of
glucose to produce energy and in the enzymes needed to synthesize the neurotransmitters,
serotonin and dopamine. |
| RDA |
15 mg per day for menstruating women. 10 mg per day for men and post-menopausal
women. During pregnancy, women need 30 mg per day. |
| Therapeutic
dose |
10 to 50 mg per day. |
| Deficiency symptoms |
Anemia with its symptoms of fatigue, pale skin, weakness, headache, labored
breathing with mild exertion, hair loss, spoon-shaped, brittle fingernails,
frequent infections and light-headedness. Deficiency may be caused by
excessive menstrual bleeding, bleeding ulcers, lack of hydrochloric acid
in the stomach (common in the elderly), overuse of anti-acids, diarrhea
or other intestinal malabsorption disorders. Iron deficiency anemia is
the second most common nutritional deficiency worldwide (after protein-calorie
malnutrition). |
| Toxicity |
Iron toxicity is rare because the body absorbs less iron when reserves are
adequate. However, iron is susceptible to oxidation (rust), and is implicated
in cardiovascular disease for providing a binding site for cholesterol on
the artery wall. Acute iron toxicity occurs in about 2,000 cases per year
in children who consume adult strength iron tablets. Iron poisoning in children
is second only to poisoning by Aspirin. A genetic disorder known as hemochromatosis
causes increased iron absorption. Iroiin poisoning causes damage to the
heart, liver, spleen and pancreas. Iron toxicity may also occur in persons
who cook with iron and stainless steel cookware. Alcoholics may also absorb
too much iron due to intestinal and liver damage. |
| Best
forms
|
Ferrous fumerate (same as ferrous sulfate but without the gastrointestinal
distress). Ferrous sulfate can cause nausea, constipation and abdominal
discomfort. |
| Food
sources |
Liver is the richest source of iron. Other sources include meat, fish, shellfish,
poultry, beans (especially lentils), whole grains, molasses, brown sugar,
figs, prunes and raisins. |
| Lab
tests |
Serum ferritin, hemoglobin |
| Drug
interactions |
Iron is depleted by Aspirin, Chlortetracycline, Cholestryramine Resin, Choline
Magnesium, Choline Salicylate, Cimetidine, Colestipol, Demeclocycline, Doxycycline,
famotidine, Indomethacin, Minocycline, Neomycin, Nizatidine, Nonsteroidal
Anti-Inflammatories, Oxytetracycline, Ranitidine bismuth Citrate, Ranitidine
Hydrochloride, Tetracyclines. |
| Nutrient interactions |
Vitamin E inhibits the absorption of iron. It is better to take iron and
Vitamin E at different meals. |
| Metabolism |
Heme iron is better
absorbed than non-heme iron. Though heme iron may only be 10% or total
dietary iron, it can provide up to 30% of he total absorbed iron. Heme
and non-heme iron are found in animal products while only non-heme iron
is found in plant sources. Iron is absorbed in the mucosal cells of the
proximal jejunum and bound with plasma transferrin to be carried to the
cells of the body. Iron is stored primarily in the bone marrow and liver.
It is stored primarily in the bone marrow as ferritin to make hemoglobin.
It is also stored in the liver as hemosiderin. Iron is conserved by the
body. Other than menstrual or other bleeding, iron is lost primarily through
sloughing off of skin and gastrointestinal cells.
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