Iron

This chapter presents aspects of iron metabolism, the requirement for iron, food iron content, iron chemistry, processing effects on iron in food, and iron and immunity. Primary emphasis are given to iron absorption, particularly to the lumenal behavior of nonheme iron. More recently, this same laboratory has presented evidence that unoxidized cysteine-containing peptides released during digestion of beef could enhance nonheme iron absorption. Consequently, the effect of substituting soy products for meat is less strong on two counts: the iron content of soy products is high, and an enhancing effect on heme iron absorption accompanies the inhibitory effect of nonheme iron absorption. Slower gastric emptying and increased heme and nonheme iron absorption were observed for the treated meal. Although the chemical state of iron was determined, it would be anticipated that iron bioavailability from a meal would be decreased based on the loss of this enhancer of nonheme iron absorption.