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

Abstract

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.

Consumption of highly processed foods: Effects on bioavailability and status of zinc and copper in adolescents

“…Although Lykken et al (1986) reported the inhibition of zinc absorption when volunteers consumed isolated browned foods compared to unbrowned products, Johnson (1991) observed that the consumption of a MRP-rich diet has no effect on zinc absorption, in agreement with the results observed in the present study.…”

Dietary interventions to prevent zinc deficiency

“…In some legumes, heat treatment may actually result in the formation of insoluble calcium and magnesium phytate salts from soluble potassium salts (17). In general, use of excessive or harsh heat treatments (eg, extrusion cooking) is not a practical method for destroying phytic acid because such treatments also reduces nutrient bioavailability (including zinc) by causing chemical changes (18,19). Mild heat treatment increases the digestibility of most foods and appears to reduce the phytic acid content of tubers, but not of cereals and legumes (11).…”

Effects of oxidized lipids (4,5 (E)-epoxy-2(E)-heptenal and 4,5 (E)-epoxy-2 (E) -decenal) and lysine reaction products on zinc and calcium utilization: assays in Caco-2 cells

“…La capacidad de los PRM azúcar-aminoácido para acomplejar diversos minerales, entre los que se encuentra el Zn, ha sido demostrada tanto in vitro Homma y Murata, 1994;Delgado-Andrade, 2002) como in vivo (Andrieux y Saquet, 1984;Lykken et al, 1986). Los complejos formados pueden ser solubles o insolubles, teniendo distinta reactividad según su estructura.…”