IRON SUPPLEMENTS AND ZINC IN PREGNANCY AND LACTATION

这是一个普遍的做法，给补充铁的所有孕妇在世界各地。 剂量可以从60 mg/d到240 mg/d不等。 当规定了治疗剂量的铁，这是罕见的，也规定补充锌。 对实验动物和人类的研究表明，补充铁会干扰锌的吸收。 在我们最近进行的一项关于怀孕期间锌吸收的纵向研究中，研究的14名妇女中有4名被医生处方补充铁。虽然锌的吸收增加，在怀孕期间达到一个显着的变化，在哺乳期，这种调整没有观察到的四名妇女补充铁。 吸收锌的需要量在怀孕期间增加0.7 mg/d，在哺乳早期增加1.4 mg/d。 我们的研究表明，如果不给予补充铁，则通过上调锌吸收来满足这种需求。 补充铁的管理可能会削弱这种变化，在锌的使用在怀孕和哺乳期。 因此，本研究的目的是确定补充铁对健康妇女在怀孕和哺乳期间锌利用的代谢调节的影响。 我们假设，每天补充100毫克铁抑制锌的吸收，并减少净吸收锌从胃肠道在妊娠后期和哺乳早期时，额外需要锌是最大的。 将在妊娠早期招募两组各15名女性，并在妊娠12-14周、32-34周和产后4-6周进行研究。 一组将每天接受100 mg补充铁;另一组将不补充。 所有妇女将给予产前维生素补充剂加上8 mg铁和5 mg锌，以确保整个研究期间微量营养素的稳定基础摄入。 使用稳定同位素，铁和锌的吸收和锌动力学将被测量。 还将确定铁和锌状况的生化措施。 在每次测试期间，所有女性将在代谢单位居住6天。 这项综合性纵向研究的结果将为孕期和哺乳期补铁对锌利用的影响提供新的数据。

It is a common practice to give supplemental iron to all pregnant women world-wide. The dose can vary from 60 mg/d to as much as 240 mg/d. When therapeutic doses of iron are prescribed, it is rare to also prescribe supplemental zinc. Studies in experimental animals and humans show that supplemental iron interferes with zinc absorption. In a recent longitudinal study of zinc absorption during pregnancy done by us, four of the 14 women studied were prescribed supplemental iron by their physicians. Although zinc absorption increased during pregnancy reaching a significant change during lactation, this adjustment was not observed in the four women taking supplemental iron. The need for absorbed zinc increases by 0.7 mg/d during pregnancy and 1.4 mg/d during early lactation. Our study showed that this need is met by upregulating zinc absorption if supplemental iron is not given. Administration of supplemental iron may impair this change in zinc use during pregnancy and lactation. The purpose of this proposed study, therefore, is to define the effect of supplemental iron on the metabolic adjustments in zinc utilization in healthy women during pregnancy and lactation. We hypothesize that a daily supplement of 100 mg iron inhibits zinc absorption and reduces the net uptake of zinc from the gastro-intestinal tract during late pregnancy and early lactation when the additional need for zinc is the greatest. Two groups of 15 women each will be recruited in early pregnancy and will be studied at 12-14, 32-34 weeks of gestation, and at 4-6 weeks postpartum. One group will receive 100 mg supplemental iron daily; the other group will be unsupplemented. All women will be given a prenatal vitamin supplement plus 8 mg iron and 5 mg zinc to assure a stable basal intake of the micronutrients throughout the study. Using stable isotopes, iron and zinc absorption and zinc kinetics will be measured. Biochemical measures of iron and zinc status will also be determined. All women will reside in a metabolic unit for 6 days during each test. Results from this comprehensive, longitudinal study will provide new data on the effects of iron supplementation on zinc utilization during pregnancy and lactation.