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Iron Excess


Larry E. Johnson

, MD, PhD, University of Arkansas for Medical Sciences

Last full review/revision Jun 2020| Content last modified Jun 2020
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Iron excess occurs when the body has too much of the mineral iron.

Much of the iron in the body is contained in hemoglobin. Hemoglobin is the component of red blood cells that enables them to carry oxygen and deliver it to the body’s tissues. Iron is also an important component of muscle cells and is necessary for the formation of many enzymes in the body. (See also Overview of Minerals.)

Food contains two types of iron:

  • Heme iron: Animal products contain heme iron. It is absorbed much better than nonheme iron.

  • Nonheme iron: Most foods and iron supplements contain nonheme iron. It accounts for more than 85% of iron in the average diet. However, less than 20% of nonheme iron that is consumed is absorbed into the body. Nonheme iron is absorbed better when it is consumed with animal protein and with vitamin C.

Excess iron can accumulate in the body. Causes include the following:

  • Repeated blood transfusions

  • Iron therapy given in excessive amounts or for too long

  • Chronic alcoholism

  • An overdose of iron

  • A hereditary disorder called hemochromatosis

Excess iron consumed all at once causes vomiting, diarrhea, and damage to the intestine and other organs. Excess iron consumed over a period of time may damage the heart and the liver.

Often, deferoxamine is given intravenously. This drug binds with iron and carries it out of the body in urine. Hemochromatosis is treated with bloodletting (phlebotomy).

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