Prenatal iron supplements impair zinc absorption in pregnant Peruvian women

Prenatal iron supplements may adversely influence zinc absorption during pregnancy. To examine the impact of prenatal iron supplements on supplemental zinc absorption, fractional zinc absorption was measured in 47 pregnant Peruvian women during the third trimester of pregnancy (33 +/- 1 wk gestation). Of these 47 women, 30 received daily prenatal supplements from wk 10-24 of pregnancy until delivery. Supplements contained 60 mg of Fe and 250 microg of folate without [iron group (Fe), n = 16] or with [iron and zinc supplemented group (Fe + Zn), n = 14] 15 mg of Zn. The remaining 17 women [unsupplemented control group (C)] received no prenatal supplementation. Zinc concentrations were measured in plasma, urine and cord blood and percentage zinc absorption was determined following dosing with oral ((67)Zn) and intravenous ((70)Zn) stable zinc isotopes. Percentage zinc absorption was significantly lower than controls in fasting women receiving iron- containing prenatal supplements (20.5 +/- 6.4 vs. 20.2 +/- 4.6 vs. 47.0 +/- 12.6%, Fe, Fe + Zn and C groups, respectively, P: < 0.0001, n = 40). Plasma zinc concentrations were also significantly lower in the Fe group compared to the C group (8.2 +/- 2.2 vs. 9.2 +/- 2.2 vs. 10.9 +/- 1. 8 micromol/L, Fe, Fe + Zn and C groups, respectively, P: = 0.002), and cord zinc concentrations were significantly related to maternal plasma Zn levels (y = 6.383 + 0.555x, r = 0.486, P: = 0.002). The inclusion of zinc in prenatal supplements may reduce the potential for iron supplements to adversely influence zinc status in populations at risk for deficiency of both these nutrients.     

Influence of prenatal iron and zinc supplements on supplemental iron absorption, red blood cell iron incorporation, and iron status in pregnant Peruvian women

BACKGROUND: It is estimated that 60% of pregnant women worldwide are anemic. OBJECTIVE: We aimed to examine the influence of iron status on iron absorption during pregnancy by measuring supplemental iron absorption, red blood cell iron incorporation, and iron status in pregnant women. DESIGN: Subjects were 45 pregnant Peruvian women (33+/-1 wk gestation), of whom 28 received daily prenatal supplements containing 60 mg Fe and 250 microg folate without (Fe group, n = 14) or with (Fe+Zn group, n = 14) 15 mg Zn, which were were consumed from week 10 to 24 of gestation until delivery. The remaining 17 women (control) received no prenatal supplementation. Iron status indicators and isotopes were measured in maternal blood collected 2 wk postdosing with oral (57Fe) and intravenous (58Fe) stable iron isotopes. RESULTS: Maternal serum ferritin and folate concentrations were significantly influenced by supplementation (P < 0.05). Serum iron was also significantly higher in the Fe than in the Fe+Zn (P < 0.03) or control (P < 0.001) groups. However, the supplemented groups had significantly lower serum zinc concentrations than the control group (8.4+/-2.3 and 10.9+/-1.8 micromol/L, respectively, P < 0.01). Although percentage iron absorption was inversely related to maternal serum ferritin concentrations (P = 0.036), this effect was limited and percentage iron absorption did not differ significantly between groups. CONCLUSIONS: Because absorption of nonheme iron was not substantially greater in pregnant women with depleted iron reserves, prenatal iron supplementation is important for meeting iron requirements during pregnancy.     

Changes in iron status during pregnancy in peruvian women receiving prenatal iron and folic acid supplements with or without zinc

BACKGROUND: Iron deficiency anemia is the most prevalent nutrient deficiency during pregnancy, yet there are few data on the effect of prenatal iron supplementation in women in developing countries. OBJECTIVE: Our objective was to describe the effect of iron supplementation on hematologic changes during pregnancy, and the effect on those changes of adding zinc to the supplements. DESIGN: Pregnant women were enrolled in a randomized, double-masked study conducted at a hospital in a shantytown in Lima, Peru. Women were supplemented daily from 10-24 wk gestation to 4 wk postpartum with 60 mg Fe and 250 microg folic acid with or without 15 mg Zn. Hemoglobin and ferritin concentrations were measured in 645 and 613 women, respectively, at enrollment, at 28-30 and 37-38 wk gestation, and in the cord blood of 545 neonates. RESULTS: No differences in iron status were detected by supplement type, but hematologic changes were related to initial hemoglobin status. Women with anemia (hemoglobin <110 g/L) showed steady increases in hemoglobin concentration throughout pregnancy whereas women with relatively higher initial hemoglobin concentrations had declining values during mid pregnancy, then rising values by 37-38 wk gestation. Women with an initial hemoglobin concentration >95 g/L showed increases in serum ferritin by the end of the pregnancy. Despite supplementation, women with poorer hematologic status; who were younger, single, and multiparous; and who consumed fewer supplements were more likely to have anemia at the end of pregnancy. CONCLUSIONS: These hematologic changes are congruent with the effects of iron supplementation reported in placebo-controlled trials and the addition of zinc did not significantly affect them.     

Effect of zinc supplements on the intestinal absorption of calcium

Pharmacologic doses of zinc are widely used as zinc supplements. As calcium and zinc may compete for common absorption sites, a study was carried out on the effect of a pharmacologic dose of zinc on the intestinal absorption of calcium in adult males. The analyzed dietary zinc intake in the control studies was normal, averaging 14.6 mg/day. During the high zinc study, 140 mg zinc as the sulfate was added daily for time periods ranging from 17 to 71 days. The studies were carried out during both a low calcium intake averaging 230 mg/day and during a normal calcium intake of 800 mg/day. Calcium absorption studies were carried out during the normal and high zinc intake by using an oral tracer dose of Ca47 and determining plasma levels and urinary and fecal excretions of Ca47. The study has shown that, during zinc supplementation, the intestinal absorption of calcium was significantly lower during a low calcium intake than in the control study, 39.3% vs 61% respectively, p less than 0.001. However, during a normal calcium intake of 800 mg/day, the high zinc intake had no significant effect on the intestinal absorption of calcium. These studies have shown that the high zinc intake decreased the intestinal absorption of calcium during a low calcium intake but not during a normal calcium intake.     

Hepcidin and iron status among pregnant women in Bangladesh

Although hepcidin, a recently discovered peptide hormone, is considered a major regulator of iron metabolism and anemia in chronic inflammation, its role in anemia during pregnancy has not been characterized. Our objective was to characterize the role of hepcidin in anemia during pregnancy. We examined the relationships between urinary hepcidin, iron status indicators, hemoglobin, erythropoietin, alpha-1 acid glycoprotein, and C-reactive protein in a cross-sectional study conducted among 149 pregnant rural Bangladeshi women with biospecimens obtained during home visits. Urinary hepcidin was measured using surface-enhanced laser desorption/ ionization time-of-flight mass spectrometry. Urinary hepcidin, as log(intensity per mmol/L creatinine), was correlated with log ferritin (r = 0.33, p <0.001), the transferrin receptor index (r = -0.22, p = 0.007), and log alpha-1 acid glycoprotein (r = 0.20, p = 0.01), but not hemoglobin (r = 0.07, p= 0.40), log transferrin receptor (r = -0.07, p = 0.41), log erythropoietin (r = -0.01, p = 0.88) or log C-reactive protein (r = 0.06, p = 0.48). The strength of the relationship between hepcidin and ferritin was maintained in multiple linear regression analyses after enhancing the sample with data from women selected for low iron stores (n = 41). Among pregnant women in a community-based study in rural Bangladesh, urinary hepcidin levels were related to iron status and AGP but not hemoglobin, erythropoietin, or C-reactive protein.     

Supplementation with zinc between meals has no effect on subsequent iron absorption or on iron status of Chilean women

OBJECTIVE: Studies on the effect of zinc (Zn) supplementation on iron absorption and iron status have shown mixed results. We investigated the effect of daily supplementation with 20 mg of Zn for a period of 2 mo on iron absorption and iron status of Chilean women. METHODS: Forty-four non-anemic, clinically healthy women 35 to 45 y of age were randomly selected to receive daily 20 mg of Zn, as Zn sulfate, or a placebo between meals for a period of 2 mo. Iron and zinc biochemical indicators and iron absorption studies were assessed at baseline and at the end of the study. Iron absorption was measured using the double radioisotopic technique. RESULTS: The geometric mean (range +/- 1 standard deviation) absorption of iron before supplementation between the Zn-supplemented and placebo groups was similar (31.2, 11.2 +/- 86.3, versus 27.4, 14.4 +/- 52.2, respectively, P = 0.97). Absorption increased significantly after the 2-mo supplementation period (P = 0.049), but there were no group-wise differences at the end of the trial (34.4, 17.5 +/- 67.3, versus 39.8, 20.9 +/- 75.8, respectively, P = 0.97). The geometric mean plasma Zn concentrations did not change significantly in either group during the course of the study (P = 0.47). There was no significant effect of Zn supplementation on any of the iron indicators studied. CONCLUSION: Supplementation of 20 mg of Zn between meals for a period of 2 mo had no effect on subsequent iron absorption or iron status of Chilean women.     

孕晚期母亲铁状态对胎盘ferroportin1表达的影响

目的研究孕晚期母亲不同铁营养状态下胎盘ferroportin1(FP1)的蛋白定位、蛋白表达及其mRNA的表达。方法临床选择不同铁营养状态的孕妇,收集分娩时的胎盘。采用免疫组织化学方法测定FP1蛋白的定位,Western Blot测定蛋白表达量的变化,采用实时定量RT-PCR测定mRNA表达。结果FP1蛋白主要表达在人足月胎盘的合体滋养细胞(STB)胞浆;母亲不同铁营养状态下胎盘FP1蛋白和mRNA的表达均无明显变化。结论孕晚期胎盘FP1蛋白和mRNA的表达不受孕妇铁状态的影响。     

Effect of zinc supplements on the intestinal absorption of calcium.

Pharmacologic doses of zinc are widely used as zinc supplements. As calcium and zinc may compete for common absorption sites, a study was carried out on the effect of a pharmacologic dose of zinc on the intestinal absorption of calcium in adult males. The analyzed dietary zinc intake in the control studies was normal, averaging 14.6 mg/day. During the high zinc study, 140 mg zinc as the sulfate was added daily for time periods ranging from 17 to 71 days. The studies were carried out during both a low calcium intake averaging 230 mg/day and during a normal calcium intake of 800 mg/day. Calcium absorption studies were carried out during the normal and high zinc intake by using an oral tracer dose of Ca47 and determining plasma levels and urinary and fecal excretions of Ca47. The study has shown that, during zinc supplementation, the intestinal absorption of calcium was significantly lower during a low calcium intake than in the control study, 39.3% vs 61% respectively, p less than 0.001. However, during a normal calcium intake of 800 mg/day, the high zinc intake had no significant effect on the intestinal absorption of calcium. These studies have shown that the high zinc intake decreased the intestinal absorption of calcium during a low calcium intake but not during a normal calcium intake.     

Zinc supplementation reduces fractional zinc absorption in young and elderly korean women

BACKGROUND: Adjustments in zinc losses and absorption are thought to maintain zinc homeostasis with changes in intake, but the capacity to make these adjustments appears to be affected by aging. Zinc status of the individual may also influence adjustments in fractional zinc absorption. OBJECTIVE: The purpose of this study was to compare the effects of changes in zinc status due to zinc supplementation on fractional zinc absorption in young and elderly Korean women. DESIGN: Zinc status and absorption were measured initially in 15 young (20-24 yr) and 15 elderly women (64-75 yr) confined to a metabolic unit and consuming a typical Korean diet. Upon discharge from the unit the women were supplemented with 22 mg zinc/d for 28 days. On d 20, the women returned to the unit for measurement of zinc status and absorption. Fractional zinc absorption (FZA) was estimated from the same typical Korean breakfast at both time points using the dual isotopic tracer method. Zinc stable isotopic ratios were measured in urine samples collected for 3 days following isotope administration. RESULTS: Plasma and urinary zinc concentrations increased significantly with zinc supplementation in the young but not the elderly women. FZA decreased following zinc supplementation in the young women from 22 to 8% (p < 0.0001) and in the elderly women from 19 to 10% (p < 0.0001). The decline in young women was greater than that in elderly women (p < 0.05). CONCLUSIONS: Both young and elderly women reduced their efficiency of zinc absorption with zinc supplementation. But, plasma and urinary zinc concentrations did not increase in the elderly following zinc supplementation suggesting that age altered the use of the additional zinc.     

贫血孕妇铁与维生素A营养状况分析

目的 了解妊娠妇女铁、维生素A、核黄素等营养素的摄入及贫血的患病情况，为开展营养干预提供科学依据。方法随机抽取山东省莘县430名贫血孕妇和292名非贫血孕妇，采用24h回顾法比较2组孕妇主要营养素摄入情况，分析孕妇维生素A、核黄素及铁的营养水平。结果2组孕妇膳食均以粮谷类等植物性食物为主，铁的摄入量接近膳食推荐摄入量（RNIs）；血清检验结果显示，贫血组的铁营养水平明显低于非贫血组；85．2％贫血孕妇血浆铁蛋白〈14μg／L，转铁蛋白受体平均为31．42nmol／L；贫血组缺乏维生素A和核黄素的比例分别为62．9％和63．1％，明显高于相应的非贫血组（P〈0．01）。结论贫血不仅与铁的吸收利用率有关，而且与维生素A、核黄素摄入不足或缺乏有密切关系。     

孕妇心理对妊娠结局的影响

目的了解孕妇心理状况和妊娠结局之间的关系,为孕期保健提供依据。方法应用症状自评量表(SCL-90)和自评抑郁量表(SDS)对243例妊娠中期孕妇进行调查,在其分娩时记录各产程时间和产时出血量,并对新生儿记录Apgar评分。结果243例孕妇的SCL-90总分均值为(25.16±20.58)分,其中躯体化、强迫、抑郁、焦虑、敌对、恐怖、偏执7个因子以及SCL阳性项目数得分显著高于常模;SCL-90评价指标和妊娠结局之间无相关性;SDS量表总均分高于我国女性常模;SDS单项分18项高于女性常模;抑郁组的产程、产后出血以及新生儿评分Apgar与对照组比较,差异有统计学意义(P<0.05)。结论妊娠中期孕妇心理健康可以影响到胎儿,导致新生儿Apgar评分改变,因此,应加强围生期保健工作,以提高妊娠质量,使妊娠和分娩顺利进行,以促进母子的身心健康。     

1139例妊娠期妇女缺铁性贫血的调查分析

目的调查了解武汉市中心城区孕妇缺铁性贫血概况及其相关因素,提出干预措施,提高围产保健质量。方法对在武汉市江岸区妇幼保健院围产保健门诊进行产前检查的1139例孕妇进行膳食问卷调查,并统一由检验科进行采血样检验。结果妊娠期妇女缺铁性贫血总发生率为9．4％,其中,轻度贫血占贫血总数的96．3％,中度贫血占3．7％,无重度贫血患者。随着孕期的增加,贫血患病率增高,孕晚期发病率最高（14．9％）,各孕期孕妇贫血患病率比较差异有统计学意义∥值分别为9．180、4．038、24．281,P〈0．01或〈0．05。孕妇贫血还与年龄、文化程度密切相关,随着孕妇年龄的增大、文化程度的降低,贫血的发生率逐渐升高。结论妊娠期妇女缺铁性贫血发病率较高,且多发生在中、晚孕期。因此,应加强孕期保健宣传工作,制定干预措施,并从孕早期开始补充铁剂,降低孕妇贫血发生率,从而减少贫血对孕妇和胎儿的不良影响。     

孕妇锌 铜 钙 磷营养状况对新生儿的影响

目的 :观察孕妇锌、铜、钙、磷营养状况对新生儿的影响。方法 :测定未孕妇女及孕妇血清和新生儿脐血锌、铜、钙、磷水平 ,并对孕妇进行膳食调查。结果 :孕期血清锌有下降趋势 ,血清铜、磷显著升高 ,脐血锌、钙高于母血水平 ,铜、磷低于母血水平 ;孕晚期锌与新生儿出生体重呈正相关 ;孕妇膳食中锌、钙摄入量不足。结论 :孕妇锌、铜、钙、磷营养状况对新生儿有一定的影响     

孕妇锌 铜 钙 磷营养状况对新生儿的影响

目的观察孕妇锌、铜、钙、磷营养状况对新生儿的影响.方法测定未孕妇女及孕妇血清和新生儿脐血锌、铜、钙、磷水平,并对孕妇进行膳食调查.结果孕期血清锌有下降趋势,血清铜、磷显著升高,脐血锌、钙高于母血水平,铜、磷低于母血水平;孕晚期锌与新生儿出生体重呈正相关;孕妇膳食中锌、钙摄入量不足.结论孕妇锌、铜、钙、磷营养状况对新生儿有一定的影响.     

Relationship between the iron status of pregnant women and their newborns

OBJECTIVE: To determine the relationship between iron nutritional status of pregnant women and their newborns using a combination of hematological and biochemical parameters for the diagnosis of iron deficiency. METHODS: A cross-sectional study was conducted in Jundiaí, Southeastern Brazil, in 2000. Venous blood samples collected from 95 pregnant women and from their umbilical cord and used for the determination of complete blood count, serum iron, total iron-binding capacity, serum ferritin, zinc protoporphyrin, and transferrin saturation. Women were classified into three groups: anemic, iron deficient and non-iron deficient. Statistical analysis included the Tukey-HSD test, Pearson's correlation coefficient and multiple linear regression analysis. RESULTS: Among pregnant women, 19% were anemic (97.9% mildly anemic and 2.1% moderately anemic) and 30.5% were iron deficient. No significant difference was seen in mean values of any parameter studied between newborns in the three groups (p>0.05). Multiple linear regression analysis showed weak association between neonatal and maternal parameters. CONCLUSIONS: The iron nutritional status of pregnant women with iron deficiency or mild anemia does not seem to have a significant impact on the iron levels of their children.     

The effect of combined dietary iron, calcium and folic acid supplementation on apparent 65Zn absorption and zinc status in pregnant rats

In the present study the effect of combined iron, calcium and folic acid supplementation of the diet on 65Zn retention and zinc status was studied in the pregnant rat. Female Wistar rats were fed on a low- (8 micrograms/g) or high- (60 micrograms/g) Zn diet for 14 d and then mated overnight. After mating, half the rats were fed on the low- or high-Zn diet as before, whilst the other half were fed on similar diets supplemented with Fe, Ca and folic acid. The level of supplementation was chosen to reflect proportionately the possible increase in daily intakes of these nutrients by pregnant women. Rats which did not mate successfully were used as non-pregnant controls. On day 18 of pregnancy, each animal was given a meal of the appropriate diet labelled extrinsically with 65Zn, and on day 20 rats were killed. Carcass 65Zn retention was lower in pregnant and non-pregnant rats fed on the supplemented diets compared with those fed on the unsupplemented diets. Rats which consumed the supplemented diets throughout pregnancy had reduced plasma Zn concentrations but femur and fetal Zn concentrations were unaffected. Maternal femur Ca and fetal Fe concentrations were lower in the high-Zn groups compared with rats fed on low-Zn diets. It was concluded that the risk of inducing fetal Zn depletion as a consequence of Fe, Ca and folic acid supplementation during pregnancy appeared to be slight.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adding zinc to prenatal iron and folate supplements improves maternal and neonatal zinc status in a Peruvian population.

BACKGROUND: Maternal zinc deficiency during pregnancy may be widespread among women in developing countries, but few data are available on whether prenatal zinc supplementation improves maternal and neonatal zinc status. OBJECTIVE: We studied whether maternal zinc supplementation improved the zinc status of mothers and neonates participating in a supplementation trial in a shantytown in Lima, Peru. DESIGN: Beginning at gestation week 10-24, 1295 mothers were randomly assigned to receive prenatal supplements containing 60 mg Fe and 250 microg folate, with or without 15 mg Zn. Venous blood and urine samples were collected at enrollment, at gestation week 28-30, and at gestation week 37-38. At birth, a sample of cord vein blood was collected. We measured serum zinc concentrations in 538 women, urinary zinc concentrations in 521 women, and cord zinc concentrations in 252 neonates. RESULTS: At 28-30 and 37-38 wk, mothers receiving zinc supplements had higher serum zinc concentrations than mothers who did not receive zinc (8.8 +/- 1.9 compared with 8.4 +/- 1.5 micromol/L and 8.6 +/- 1.5 compared with 8.3 +/- 1.4 micromol/L, respectively). Urinary zinc concentrations were also higher in mothers who received supplemental zinc (P < 0.05). After adjustment for covariates and confounding factors, neonates of mothers receiving zinc supplements had higher cord zinc concentrations than neonates of mothers who did not receive zinc (12.7 +/- 2.3 compared with 12.1 +/- 2.1 micromol/L). Despite supplementation, maternal and neonatal zinc concentrations remained lower than values reported for well-nourished populations. CONCLUSION: Adding zinc to prenatal iron and folate tablets improved maternal and neonatal zinc status, but higher doses of zinc are likely needed to further improve maternal and neonatal zinc status in this population.     

Supplemental zinc lowers measures of iron status in young women with low iron reserves

Zinc and iron compete during intestinal absorption, but postabsorptive interactions between these nutrients are less clear. Understanding these interactions is important to determine when supplementation with iron or zinc is proposed. The effect of zinc supplementation (22 mg Zn/d as zinc gluconate) or of iron supplementation (100 mg Fe/d as ferrous sulfate) for 6 wk on iron and zinc metabolism and absorption was evaluated in young women with low iron reserves. Young adult women (ages 20-28 y), nonanemic but with low iron stores (plasma ferritin< 20 microg/L), participated in the 70-d study. The women were divided in two groups (zinc-supplemented, n = 11; iron-supplemented, n = 12). The supplements were taken at bedtime. Iron and zinc biochemical indices and intestinal absorption were measured on d 1 and 56. Radioiron and stable isotopes of zinc were used to measure iron and zinc absorption from a test meal. In the iron-supplemented group, blood hemoglobin, plasma ferritin and the percentage of transferrin saturation increased (P < 0.01). Zinc indices did not change. In the zinc-supplemented group, plasma ferritin and the percentage of transferrin saturation decreased (P < 0.05), whereas the plasma transferrin receptor and erythrocyte zinc protoprophyrin levels increased (P < 0.05). Plasma and urinary zinc also increased (P < 0.01). Iron absorption (%) from the test meal increased (P < 0.01), whereas zinc absorption (%) decreased (P < 0.01) compared with baseline in the Zn-supplemented women. Our results indicate that the use of iron supplements in women with marginal iron status improves iron indices with no effect on zinc status. However, use of a modest zinc supplement improves zinc indices, but also appears to induce a cellular iron deficiency and, possibly, further reduce iron status.     

Effect of milk and lactose on zinc absorption in lactose-intolerant postmenopausal women

We evaluated the effect of lactose intolerance on intestinal zinc absorption under various test conditions in a group of postmenopausal women. Fractional zinc absorption was studied with a dual-isotope technique using 65Zn and 51Cr (as nonabsorbable fecal markers). We performed four absorption tests on sixteen subjects with water (control), whole cow milk, lactose-free cow milk and lactose alone. Mean (+/- SEM) fractional zinc absorption was 0.558 +/- 0.032 with water, 0.276 +/- 0.031 with milk, 0.246 +/- 0.028 with lactose-free milk and 0.564 +/- 0.051 with lactose. No significant differences in zinc absorption were found under any of the test conditions between lactose-tolerant and lactose-intolerant subjects. Milk and lactose-free milk significantly reduced zinc absorption in both groups.