Reduction of iron in the human stomach.

It has been shown that the oral administration of ferrous compounds, as compared with ferric salts of iron, resulted in somewhat more rapid absorption of iron from the gastrointestinal tract (results of studieswith radioactive isotopes (l)), and more rapid hemoglobin formation in anemia due to iron deficiency (2). From these results and from the fact that ferrous compounds in general are much more soluble than the corresponding ferric compounds, the theory arose that ferric compounds might be reduced in the intestines to ferrous forms and that this change was essential for absorption. It seemed clear that iron might be reduced in the large intestines, and to a lesser extent in the small intestines, through the action of hydrogen sulfide and other products of bacterial action (3). Histological evidence, however, suggested that iron might be absorbed in the upper small intestine, although no quantitative evidence of the reduction of iron salts there had been presented. New light was thrown on this matter when it was suggested by Tompsett (4) that iron might be reduced by foods in the stomach. He supported this view with demonstrations that iron might be reduced by certain foods when treated with pepsin-hydrochloric acid solutions. While his results were not quantitative and the dipyridyl reaction used was not, as we have shown, well adapted for this purpose, the findings were of great interest. Because of the important bearing that reduction of iron in the stomach and small intestines might have on iron absorption and metabolism, it was decided to carry out studies on human and animal subjects to determine where and to what extent iron was actually reduced in tivo. Since no suitable method existed for determining ferrous and ferric iron in our materials, it was necessary to develop one. This method is described in an earlier report (5). Also reported there are results showing the reduction of iron by various types of foods in artificial gastric digestion. The present report deals with the reduction of ferric iron present in or added to foods when these are digested in the human stomach.