Cereal Chem 68:194-200   |  VIEW ARTICLE

Bioavailability of Total Dietary Iron from Beef and Soy Protein Isolate, Alone or Combined, in Anemic and Healthy Rats.

D. Zhang, D. G. Hendricks, A. W. Mahoney, Y. Yu, A. M. Thannoun, and D. V. Sisson. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Bioavailability of iron from beef, soy protein isolate (SPI), and proportional mixtures of beef and SPI was measured in anemic and healthy weanling rats. Diets were prepared by mixing beef and SPI with dietary ingredients at beef-to-SPI iron ratios of 100:0, 75:25, 50:50, 25:75, or 0:100. A casein diet supplemented with FeSO4 was used as the reference diet. The respective mean hemoglobin regeneration efficiency (HRE) and apparent iron absorptions were 37 and 44% for anemic rats and 42 and 37% for healthy rats when the beef-based diet was fed, and 56 and 66% for anemic rats and 42 and 53% for healthy rats when the SPI- based diet was fed. The HRE and apparent iron absorption were 71 and 72% for anemic and 44 and 60% for healthy rats fed the diet supplemented with FeSO4. Generally, anemic rats utilized more dietary iron than healthy rats. This iron status effect was greatest in rats fed the supplemented diet, less (but significant) in rats fed the SPI diet, and not significant in rats fed the beef diet. Beef-SPI mixtures enhanced iron bioavailability when fed to healthy rats, as indicated by a significant, positive binomial curve of the iron bioavailability values versus dietary proportions of beef and SPI iron. However, this enhancement did not occur when the beef-SPI mixtures were fed to anemic rats. The correlation coefficient between HRE and apparent iron absorption was high (r = 0.83) for the pooled data.