Effect of Browned and Unbrowned Corn Products Intrinsically Labeled with 65Zn on Absorption of 65Zn in Humans

Experimental browned and unbrowned corn products were formulated and processed from unenriched, degermed yellow corngrits. The browned product (cornflakes) contained more insoluble dietary fiber and bound more zinc (in vitro) than the unbrowned product (corngrits). During processing some of the cornflakes and corngrits were combined with a small amount of yellow corn endospermhull intrinsically labeled with 65Zn. The intrinsically labeled corn products were fed, in a crossover design, as components of two breakfasts to six normal, unconfined volunteers. Each volunteer absorbed more 65Zn from the corngrits than from the cornflakes. The reduced 65Zn absorption from cornflakes was attributed to heating and toasting reaction products, possibly Maillard, which bound zinc and consequently made the zinc less available for absorption.