Longitudinal measurements of zinc absorption in Peruvian children consuming wheat products fortified with iron only or iron and 1 of 2 amounts of zinc.

Background: Information is needed on the fractional absorption of zinc (FAZ) and absorbed zinc (AZ) during prolonged exposure to zinc-fortified foods.
Objective: The objective was to measure FAZ and AZ from diets fortified with different amounts of zinc and to determine whether zinc absorption changes over approximately 7 wk.
Design: Forty-one stunted, moderately anemic children received daily, at breakfast and lunch, 100 g wheat products fortified with 3 mg Fe (ferrous sulfate) and 0 (group Zn-0), 3 (group Zn-3), or 9 (group Zn-9) mg Zn (zinc sulfate) per 100 g flour. FAZ was measured on days 2-3 and 51-52; meal-specific AZs were calculated as the product of FAZ and zinc intake.
Results: For the breakfast and lunch meals combined, mean total zinc intakes were 2.14, 4.72, and 10.04 mg/d in groups Zn-0, Zn-3, and Zn-9, respectively, during the initial absorption studies; mean (+/-SD) FAZ values were 0.341 +/- 0.111, 0.237 +/- 0.052, and 0.133 +/- 0.041, respectively, on days 2-3 (P < 0.001) and did not change significantly on days 51-52 in the subset of 31 children studied twice. Mean initial AZ was positively related to zinc intake (0.71 +/- 0.18, 1.11 +/- 0.21, and 1.34 +/- 0.47 mg/d, respectively; P < 0.001); final values did not differ significantly from the initial values.
Conclusions: AZ from meals containing zinc-fortified wheat products increases in young children relative to the level of fortification and changes only slightly during approximately 7-wk periods of consumption. Although consumption of zinc-fortified foods may reduce FAZ, zinc fortification at the levels studied positively affects total daily zinc absorption, even after nearly 2 mo of exposure to zinc-fortified diets.