Agriculture, Maternal-Infant Nutrition & Public Health

铁和锌是两种微量营养素，被认为是发展中国家产妇，特别是婴儿发病率的主要原因。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差。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因所添加矿物质的生物利用度的不确定性而复杂化，一方面伴随着持续缺乏的风险（因依从性差而加剧），另一方面可能过量。发展中国家的典型植物性饮食，特别是未精制的谷物和豆类中存在大量植酸，被广泛认为是造成矿物质生物利用率和状态差的主要因素（以及低血红素铁）。这一假设将在危地马拉西部高地农村进行测试，玉米（用石灰处理）是主要的膳食主食，通过长期膳食植酸盐减少利用低植酸盐（65%减少）玉米。500名妇女（第1-2胎）及其婴儿的干预持续时间将从孕前至少6个月到产后一年。妇女将被随机分配到低植酸盐组（第1组）、低植酸盐加15 mg产前（妊娠12-40周）和2.5mg较大婴儿（6 - 12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周开始每天接受30 mg Fe，第2组婴儿从6-12个月开始每天接受7.5 mg Fe。这些干预措施的有效性将通过以下纵向定量测量进行评估：锌稳态变量;铁和锌状态的生物标志物;选定的孕产妇发病率和产科结局指数;胎儿和婴儿生长发育指数，包括神经行为指数;以及选定的婴儿传染病发病率和免疫状态指数。如果有益，这种干预可能易于维持和传播。在智利，将用稳定同位素技术研究营养性宫内生长迟缓（发展中国家发病的一个主要原因）与新生儿锌储存量低有关的假设。

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.