Rosado Jorge L, Díaz Margarita, Muñoz Elsa, Westcott Jamie L, González Karla E, Krebs Nancy F, Caamaño María C, Hambidge Michael
Universidad Autónoma de Querétaro, Querétaro, México.
Food Nutr Bull. 2012 Dec;33(4):261-6. doi: 10.1177/156482651203300406.
Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron.
To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability.
A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method.
The mean (+/- SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 +/- 0.07, 0.36 +/- 0.05, and 0.37 +/- 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 +/- 0.04, 0.33 +/- 0.02, and 0.32 +/- 0.05, respectively) and similar amounts of zinc absorbed (4.8 +/- 0.7, 4.5 +/- 0.3, and 4.8 +/- 0.7 mg/day, respectively).
Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour.
玉米饼是墨西哥的主食，对其进行锌、铁及其他微量营养素强化旨在减少微量营养素缺乏。然而，尚未开展研究来确定从强化产品中吸收的锌的相对量，以及锌的吸收是否会受到同时添加铁的影响。
比较添加氧化锌和硫酸锌的玉米饼中锌的吸收情况，并确定同时添加两剂铁对锌生物利用度的影响。
采用随机、双盲、交叉设计，分两个阶段进行。在第一阶段，10名成年女性分别食用添加了20mg/kg氧化锌的玉米饼、添加了20mg/kg硫酸锌的玉米饼或未添加锌的玉米饼。在第二阶段，10名成年女性食用添加了20mg/kg氧化锌的玉米饼，且要么不添加铁，要么添加两种不同水平之一的铁。通过稳定同位素法测量锌的吸收情况。
未强化的玉米饼、强化了氧化锌的玉米饼和强化了硫酸锌的玉米饼的平均（±标准误）锌吸收分数在各处理组之间无差异：分别为0.35±0.07、0.36±0.05和0.37±0.07。添加了0、30和60mg/kg铁的三个处理组的锌吸收分数相似（分别为0.32±0.04、0.33±0.02和0.32±0.05），吸收的锌量也相似（分别为4.8±0.7、4.5±0.3和4.8±0.7mg/天）。
由于氧化锌更稳定且成本更低，并且其吸收效果与硫酸锌相同，我们建议将其用于玉米饼强化。在玉米粉中铁剂量为30和60mg/kg时，同时添加锌和铁不会改变锌的生物利用度。
