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Iron Overload

Posted by Blog Monday, March 7, 2011

Certain people, about one in 200, have a predisposition to iron overload called hemochromatosis. Iron overload is very rare in individuals without a genetic predisposition, even with prolonged iron supplementation. The carefully controlled absorption of iron prevents excess in most people. People may have hemochromatosis and not know it. For this reason, adult men and postmenopausal women are normally advised not to take iron supplements.

Children are at risk of accidental overdose from products containing iron. The largest cause of death from poisoning in children under six years of age is accidental iron overdose. Iron supplements, especially potent iron supplements meant for pregnant women, should be kept out of the reach of children.

Potent iron supplements may cause stomach and intestinal irritation and other digestive discomforts. Iron supplementation may cause constipation and cause the stools to appear darker. Liquid iron supplements can even stain teeth. Iron supplements should be taken with food to prevent discomfort.


Summary for Iron


Main functions: transportation of oxygen and energy metabolism.

RDA: adults, 7 to 18 mg; pregnant women, 27 mg.

Toxicity: only affects those with a genetic disorder.

Digestive discomfort may occur if taken on an empty stomach.

Tolerable upper intake level is set at 45 mg, 40 mg for ages under 14.

Deficiency can cause fatigue and anemia. Deficiency is common.

Sources: meat, fish, poultry, green leafy vegetables, dried fruit, blackstrap molasses, nuts and seeds, and fortified grains.

Forms in the body: ferritin, transferrin, hemosiderin.



To prevent gastrointestinal discomfort, the Food and Nutrition Board of the Institute of Medicine has established tolerable upper intake levels (UL). For children under 14 years of age, the UL is 40 mg of iron. For all others the UL is 45 mg of iron. For people with genetic predispositions to iron overload and those with alcoholic cirrhosis, the safe dose may be lower. Higher doses may be prescribed for pregnant women. There has been some association between the intake of heme iron and the risk of heart attacks. When iron stores are high, heme iron absorption is not as effectively limited as is the absorption of non-heme iron. This may lead to a higher risk of heart attacks because of the free radical action of excess iron on LDL. The possibility of excess heme iron from animal sources increasing the risk of heart attacks is being investigated .

Iron Supplements

Absorption of iron from supplements depends on the form of the iron. The forms that are best absorbed and cause the least gastrointestinal discomfort are ferrous ascorbate and ferrous gluconate. Ferrous sulfate monohydrate is also well absorbed. The forms of iron supplements that are least well absorbed include ferrous fumarate, ferrous succinate, and ferric saccharate. To summarize, iron is needed to transport and store oxygen in the body. Iron is also essential in energy production in the cell. Iron deficiency is the most common nutrient deficiency in the world.


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