COMPARATIVE-STUDY IN RATS OF IRON BIOAVAILABILITY FROM COOKED BEEF AND SOYBEAN PROTEIN

Two variations of the basic depletion-repletion method were used to measure iron bioavailability from a soybean protein isolate, a processed soybean protein isolate, and cooked beef. The depletion phase was the same for all animals; however, the repletion phase compared the effects of restricted feeding to ad libitum feeding. Slope-ratio analyses of the increase in hematocrit, hemoglobin, and total hemoglobin gave the best statistical fit for the data. Although all methods of analyses gave comparable results, calculation based on total hemoglobin provided the best statistical fit to the slope-ratio analysis (i.e., linearity of response). The results showed that iron from the soybean protein isolate and iron from the processed soybean protein isolate had bioavailabilities 82-100% of ferrous sulfate. Iron from cooked beef had a bioavailability of 26-55% of ferrous sulfate. The results of these animal experiments are compared to iron absorption studies conducted in anemic and normal humans. © 1979, American Chemical Society. All rights reserved.