The absorption of radioiron labeled foods and iron salts in normal and iron-deficient subjects and in idiopathic hemochromatosis.

It is generally accepted that, in the absence of bleeding or pregnancy, approximately 1 mg. of iron is lost per day from the body (1-11). As a corollary, the quantity of iron in the body is largely determined by the amount of iron absorbed from the gastrointestinal tract. Fundamental knowledge of iron absorption has been obtained by balance studies (2, 4, 12-18), by determination of the increase in the serum iron level (19) or circulating hemoglobin (20-21) after oral iron administration, and by evaluation of the percentage of orally administered radioiron incorporated into hemoglobin (22-26) or accounted for in both hemoglobin and feces (7, 27). The present investigation was undertaken to compare the absorption of egg and vegetable iron with that of iron salts fed to normal subjects, to patients with iron-deficiency, and to patients with idiopathic hemochromatosis. The method of study used was similar to that introduced by Dubach, Callender, and Moore (27). These investigators showed that the quantity of iron used in hemoglobin formation may not always be a true index of iron absorption (27, 28). Since a negligible quantity of iron is excreted into the intestinal tract (1-3, 7-8, 11) and since stool iron is almost entirely unabsorbed dietary iron (2), additional information concerning iron absorption may be obtained by determining both the percentage of orally administered radioiron incorporated into hemo-