Further Studies on Copper and Iron

Abstract

Waddell, Steenbock, Elvehjem, and Hart 1 showed that rats fed milk exclusively developed nutritional anemia and that the ingestion of pure iron salts failed to cure it. However, normal regeneration of hemoglobin was obtained with small additions of copper sulphate along with the iron salt. These results have been confirmed by Keil and Nelson. 2 Myers and Beard 3 found that higher doses of zinc and magnesium retarded blood regeneration. If this is the case, anemia should develop more rapidly on milk and FeCl₃ if these elements are included. The slope of the curves obtained with and without zinc or magnesium demonstrate that anemia resulted as readily with or without these elements.

Prior to this work on hemoglobin regeneration, Daniels and Hutton 4 demonstrated that rats failed to reproduce on milk and iron, but reproduction was a success when a mineral mixture of NaI, NaF, KAl (SO₄)₂, MnSO₄, and Na₂SiO₃ was added. They concluded that all of these salts were necessary in the milk for reproduction. The work of Hart, Steenbock and associates 1 and Keil and Nelson 2 is so conclusive, that it is certain animals cannot grow and reproduce normally without copper. There must have been contamination of this element either in the milk or salt mixture used by Daniels and Hutton. The minimum amount of copper required for regeneration of hemoglobin is extremely small. The minimum amount of copper as CuSO₄, when injected intraperitoneally, is shown to be 0.002 mg. daily. The milk used in these experiments was collected directly into glass containers in order to avoid contamination with copper. Milk ad lib and 0.5 mg. of Fe as FeCl₃ daily were fed to the rats. 0.05 mg. of Fe as FeCl₃ injected intraperitoneally with 0.002 mg. Cu as CuSO₄ daily does not result in normal regeneration.