Understanding iron absorption and metabolism, aided by studies of hemochromatosis.

Duodenal iron absorption from food is selectively blocked to prevent iron intoxication. The prime example of pathologic increase in intestinal iron absorption is seen in patients with hemochromatosis. They suffer iron damage to the heart, liver, and other tissues resulting in premature death if the iron is not removed by vigorous phlebotomy. Examples of overcoming the intestinal barrier to iron are alcohol consumption, vitamin preparations with vitamin C, and iron consumed by individuals without anemia. Endogenous generation of excess iron by hemolysis, owing to abnormal hemoglobin or many transfusions, are not controlled by the intestinal barrier.