Agriculture, Maternal-Infant Nutrition & Public Health

铁和锌是两种微量营养素，已被认为是发展中国家产妇、特别是婴儿发病的主要原因。膳食中矿物质的摄入量不一定低，但这些矿物质的生物利用度很低。通过补充或强化来克服生物可利用矿物质数量不足的努力由于所添加矿物质的生物可利用性的不确定性而变得复杂，一方面伴随有继续缺乏的危险（由于不遵守规定而加剧），另一方面可能过量。发展中国家典型的以蔬菜为基础的饮食中存在大量植酸，特别是在未精制的谷物和豆类中，这被广泛认为是造成矿物质生物利用度和状况不佳的主要因素（加上血红素铁含量低）。这一假设将在危地马拉西部高地农村地区进行验证，在那里，玉米（用石灰处理）是主要的膳食主食，通过利用低植酸（减少65%）玉米长期减少膳食植酸。对500名妇女（1-2胎）及其婴儿进行干预的时间将从孕前至少6个月到产后一年。女性将被随机分配到低植酸组（gr 1）；低植酸盐加15毫克产前（妊娠12-40周）和2.5毫克大婴儿（612个月）锌补充剂（第2组）或野生型对照组（第3组）。所有组从妊娠12-40周每天接受30mg铁，第二组婴儿从6-12个月每天接受7.5 mg铁。这些干预措施的有效性将通过纵向定量测量来评估：锌稳态变量；铁和锌的生物标志物；选定的产妇发病率和产科结果指标；胎儿和婴儿生长发育指标，包括神经行为；并选择了婴儿传染病发病率和免疫状况的指标。如果有益，这种干预措施可能很容易维持和传播。在智利，将用稳定同位素技术检验关于营养性子宫内生长迟缓（发展中国家发病率的一个主要原因）与新生儿锌储量低有关的假设。

Iron and zinc are two micronutrients that have been implicated as major causes of maternal and, especially, infant morbidity in the developing world. Dietary intakes of minerals are not necessarily low, but bioavailability of these minerals is poor. Efforts to overcome the inadequate quantities of bioavailable mineral by supplementation or fortification are complicated by uncertainties about the bioavailability of the added mineral, with the concomitant risk of continuing deficiency on the one hand (aggravated by poor compliance) and, possibly, excess on the other. The large quantities of phytic acid present in vegetablebased diets, typical of developing countries, especially in unrefined cereal grains and legumes, are widely considered to be the major factor (together with low heme iron) responsible for poor mineral bioavailability and status. This hypothesis will be tested in the rural Western Highlands of Guatemala, where maize (treated with lime) is the principal dietary staple, by long-term dietary phytate reduction utilizing low phytate (65% reduction) maize. The duration of this intervention in 500 women (parity 1-2)-and their infants-will be from at least 6 months pre-conception to one year post-partum. Women will be randomized to a low phytate group (gr 1); low phytate plus a 15mg prenatal (12-40 weeks gestation) and 2.5 mg older infant 612 months) Zn supplement (gr 2) or to a wild type control group (gr 3). All groups will receive 30mg Fe daily from 12-40 weeks gestation and group 2 infants will receive 7.5 mg Fe /day from 6-12 months. The efficacy of these interventions will be assessed by longitudinal quantitative measurements of: variables of zinc homeostasis; biomarkers of iron and zinc status; selected maternal indices of morbidity and obstetric outcome; indices of fetal and infant growth and development, including neurobehavioral; and selected indices of infant infectious disease morbidity and immune status. If beneficial, this intervention is potentially simple to sustain and disseminate. In Chile, the hypothesis that nutritional intra-uterine growth retardation (a major cause of morbidity in developing countries) is associated with low neonatal zinc stores will be examined with stable isotope techniques.