Zinc Absorption From Agronomically Biofortified Wheat Is Similar to Post-Harvest Fortified Wheat and Is a Substantial Source of Bioavailable Zinc in Humans.

Limited data exist on human zinc absorption from wheat biofortified via foliar (FBW) or root (hydroponically fortified wheat, HBW) zinc application. Stable isotope labels added at point of consumption (extrinsic labeling) might not reflect absorption from native zinc obtained by intrinsic labeling. We measured fractional and total zinc absorption (FAZ, TAZ) in FBW and HBW wheat, compared with control wheat (CW) and fortified wheat (FW). The effect of labeling method was assessed in HBW (study 1), and the effect of milling extraction rate (EXR, 80% and 100%) in FBW (studies 2 and 3). Generally healthy adults (n = 71, age: 18-45 y, body mass index: 18.5-25 kg/m2) were allocated to 1 of the studies, in which they served as their own controls. In study 1, men and women consumed wheat porridges colabeled intrinsically and extrinsically with 67Zn and 70Zn. In studies 2 and 3, women consumed wheat flatbreads (chapatis) labeled extrinsically. Zinc absorption was measured with the oral to intravenous tracer ratio method with a 4-wk wash-out period between meals. Data were analyzed with linear mixed models. In study 1 there were no differences in zinc absorption from extrinsic versus intrinsic labels in either FW or HBW. Similarly, FAZ and TAZ from FW and HBW did not differ. TAZ was 70-76% higher in FW and HBW compared with CW (P < 0.01). In studies 2 and 3, TAZ from FW and FBW did not differ but was 20-48% higher compared with CW (P < 0.001). Extraction rate had no effect on TAZ. Colabeling demonstrates that extrinsic zinc isotopic labels can be used to accurately quantify zinc absorption from wheat in humans. Biofortification through foliar zinc application, root zinc application, or fortification provides higher TAZ compared with unfortified wheat. In biofortified wheat, extraction rate (100-80%) has a limited impact on total zinc absorption. These studies were registered on clinicaltrials.gov (NCT01775319).

Signorell C ，Zimmermann MB ，Cakmak I ，Wegmüller R ，Zeder C ，Hurrell R ，Aciksoz SB ，Boy E ，Tay F ，Frossard E ，Moretti D ... -  《-》

Zinc Absorption by Adults Is Similar from Intrinsically Labeled Zinc-Biofortified Rice and from Rice Fortified with Labeled Zinc Sulfate.

Biofortification of staple food crops is a promising strategy to combat zinc deficiency, and it is of particular interest for rice and crops that are not consumed as flours and therefore not suitable for postharvest fortification. Because zinc absorption is decreased by phytic acid (PA) and perhaps other dietary components, it is important to measure the absorption of zinc from a biofortified crop before determining its efficacy. In this study, we compared the zinc absorption from zinc-biofortified rice (hydroponically enriched with (70)Zn) with that from a control rice of the same variety fortified with (70)ZnSO4 at point of use to reach the same total zinc content of 1.1 mg/meal. Both rice meals had a PA:Zn molar ratio of 12. Fractional absorption of zinc (FAZ) was measured with the use of the double-isotope tracer ratio method in 16 apparently healthy adults [18-45 y old; BMI (in kg/m(2)) 19-25] who consumed 2 single meals at 4-wk intervals in random order in a crossover design. The FAZ from the biofortified rice (mean ± SD: 25.1 ± 8.7%) did not differ significantly from that of the point-of-use fortified rice (mean ± SD: 20.8 ± 7.1%) (P = 0.08). These results suggest that the native zinc accumulated in the biofortified rice was readily released from the rice matrix and that its absorption by adults was influenced by PA and other food components in a similar way to the inorganic zinc compound added to the rice at point of use. Moreover, rice biofortification is likely to be as good as postharvest zinc fortification as an intervention strategy to combat zinc deficiency. This trial was registered at clinicaltrials.gov as NCT01633450.

Brnić M ，Wegmüller R ，Melse-Boonstra A ，Stomph T ，Zeder C ，Tay FM ，Hurrell RF ... -  《-》

The quantity of zinc absorbed from wheat in adult women is enhanced by biofortification.

Rosado JL ，Hambidge KM ，Miller LV ，Garcia OP ，Westcott J ，Gonzalez K ，Conde J ，Hotz C ，Pfeiffer W ，Ortiz-Monasterio I ，Krebs NF ... -  《-》

Efficacy of high zinc biofortified wheat in improvement of micronutrient status, and prevention of morbidity among preschool children and women - a double masked, randomized, controlled trial.

Sazawal S ，Dhingra U ，Dhingra P ，Dutta A ，Deb S ，Kumar J ，Devi P ，Prakash A ... -  《Nutrition Journal》

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

López de Romaña D ，Salazar M ，Hambidge KM ，Penny ME ，Peerson JM ，Krebs NF ，Brown KH ... -  《AMERICAN JOURNAL OF CLINICAL NUTRITION》