STUDIES IN IRON TRANSPORTATION AND METABOLISM. IV. OBSERVATIONS ON THE ABSORPTION OF IRON FROM THE GASTRO-INTESTINAL TRACT 12

Abstract

Absorption of Fe from the intestinal tract was studied by following the increases in serum (transport) iron after Fe was given by mouth. It was demonstrated that Fe is absorbed directly into the blood stream and is not first collected by the intestinal lymph channels. Soluble, ionized ferrous salts produced similar increases in the serum iron fraction; the anion of the Fe salt did not alter the response. Corresponding ferric salts caused much smaller serum Fe rises unless ingested along with reducing substances like ascorbic acid and Na formaldehyde sulphoxylate. Bile pigment, chlorophyll, a water soluble extract of liver, and mucin failed to influence the serum Fe concs. Patients with hypochromic anemias frequently showed greater Fe absorption during their deficiency periods than after therapy. Individuals with Addi-sonian pernicious anemia in relapse, on the other hand, developed no increase in serum Fe following oral Fe adm. before specific therapy was commenced, but did thereafter. All the acutely ill patients studied likewise failed to show evidences of Fe assimilation no matter what the state of their reserves. The results confirm the notion that Fe is absorbed more readily, if not entirely as ferrous Fe. The characteristics which make an Fe salt readily absorbable are apparently its water solubility, its ease of ionization, and the bivalent state of the metal itself.