Measurement of the bioavailability of iron, using the rat hemoglobin repletion test.

Variations in the AOAC official first action rat hemoglobin repletion test for iron were studied. These changes included (1) use of a simplified basal diet to eliminate ingredients which sometimes contribute too much iron; (2) increased fortification of the basal diet with vitamin E, pantothenic acid, and pyridoxine; (3) increased dietary copper; (4) variations in the carbohydrate source in the basal diet; (5) changes in the length of the depletion and repletion periods; and (6) comparison of prophylactic and curative procedures. The changes yielded results comparable to those obtained with the present official method. Further study may reveal that the depletion period can be shortened or eliminated. To fully meet the rat's vitamin requirements, increased levels of vitamin E, pantothenic acid, and pyridoxine are recommended. It is further recommended that the present method remain in official first action status, and that study be continued.