I've been told to avoid iron pills if you can.
Once by a phlabotomist(sp). The other by ...um I forgot. But does anyone know why?
Excessive iron can be toxic, because free ferrous iron reacts with
peroxides to produce
free radicals, which are highly reactive and can damage
DNA,
proteins,
lipids, and other cellular components. Thus, iron toxicity occurs when there is free iron in the cell, which generally occurs when iron levels exceed the capacity of
transferrin to bind the iron.
Iron uptake is tightly regulated by the human body, which has no physiological means of excreting iron, so controls iron levels solely by regulating uptake. Although uptake is regulated, large amounts of ingested iron can cause excessive levels of iron in the blood, because high iron levels can cause damage to the cells of the
gastrointestinal tract that prevents them from regulating iron absorption. High blood concentrations of iron damage cells in the
heart,
liver and elsewhere, which can cause serious problems, including long-term organ damage and even death.
Humans experience iron toxicity above 20 milligrams of iron for every
kilogram of mass, and 60 milligrams per kilogram is a
lethal dose.
[15] Over-consumption of iron, often the result of children eating large quantities of
ferrous sulfate tablets intended for adult consumption, is one of the most common toxicological causes of death in children under six.
[15] The
DRI lists the Tolerable Upper Intake Level (UL) for adults as 45
mg/day. For children under fourteen years old the UL is 40 mg/day.
Regulation of iron uptake is impaired in some people as a result of a genetic defect that maps to the HLA-H gene region on chromosome 6. In these people, excessive iron intake can result in
iron overload disorders, such as
hemochromatosis.
Many people have a genetic susceptibility to iron overload without realizing it or being aware of a family history of the problem. For this reason, it is advised that people should not take iron supplements unless they suffer from iron deficiency and have consulted a doctor. Hemochromatosis is estimated to cause disease in between 0.3 and 0.8% of Caucasians.
[16]
The medical management of iron toxicity is complex, and can include use of a specific
chelating agent called deferoxamine to bind and expel excess iron from the body.
The above info is from wikipedia.
Basically, too much iron can be fatal.
A lot of multi-vitamins have a disclaimer on the labels about the overdose of iron containing products.