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.     

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.     

A national survey of iron and folate status in pregnant women in Switzerland.

Women often do not meet the increased iron and folate needs of pregnancy. Maternal iron-deficiency anemia is associated with poor maternal and infant outcomes, including preterm delivery and low birth weight. Poor folate status increases risk for maternal anemia, spontaneous abortion, and congenital defects. Because of this, supplemental iron and folate are often recommended during pregnancy. There are few data on iron and folate status in pregnant women in Switzerland. We measured iron and folate status in a national sample of Swiss pregnant women, estimated the prevalence of anemia, and determined if supplement use is associated with iron and/or folate status in this group. A 3-stage probability to size cluster sampling method was used to obtain a representative national sample of pregnant women (n = 381) in the second and third trimester. We measured hemoglobin, hematocrit, mean corpuscular volume, and serum folate and ferritin concentrations. Serum transferrin receptor concentration was determined in anemic subjects. The use of iron and folate supplements was evaluated by questionnaire. Mean hemoglobin (+/- SD) in the sample was 123 g/L (+/- 1.0). The prevalence of anemia was 6%. Of the 21 anemic women, 11 were iron-deficient, giving an iron-deficiency anemia prevalence of 3%. Nineteen percent of women had low serum ferritin concentrations (< 12 micrograms/L) and 4% had low serum folate concentration (< 2.5 micrograms/L). Supplements containing iron were taken by 65% of women, and 63% were taking folate-containing supplements. Women in the second and third trimester taking folate-containing supplements had significantly higher serum folate concentrations compared to those not taking a folate supplement (p < 0.001). In the third trimester, women taking iron-containing supplements had significantly higher serum ferritin concentrations compared to those not taking an iron-containing supplement (p < 0.01). Our findings indicate that iron and folate status appears to be adequate in the majority of pregnant women in Switzerland, and that use of iron and folate supplements may have a positive impact on status.     

Maternal hepcidin is associated with placental transfer of iron derived from dietary heme and nonheme sources

The determinants of placental transport of dietary iron remain largely uncharacterized. The objective of this research was to elucidate determinants of fetal Fe transfer from maternally ingested dietary heme and non-heme Fe. The study was undertaken in 19 pregnant females (16-32 y) who ingested intrinsically labeled (58)Fe-heme and a nonheme Fe source ((57)FeSO(4)) during the third trimester of pregnancy. At delivery, maternal and cord blood was obtained to assess neonatal (57)Fe and (58)Fe enrichment as a function of maternal/neonatal Fe status [serum ferritin (SF), transferrin receptor, hemoglobin (Hb), total body Fe, and hepcidin]. There was a greater percentage of maternally absorbed (58)Fe tracer present in the neonates compared to the (57)Fe tracer (5.4 ± 2.4 vs. 4.0 ± 1.6; P < 0.0001). Net dietary nonheme Fe (mg) and heme Fe (mg) transferred to the fetus were both inversely correlated with measures of maternal serum hepcidin (P = 0.002, r(2) = 0.43; P = 0.004, r(2) = 0.39) and SF (P = 0.0008, r(2) = 0.49; P = 0.003, r(2) = 0.41) and directly associated with neonatal Hb (P = 0.004, r(2) = 0.39; P = 0.008, r(2) = 0.35). The results of this study suggest that during pregnancy there appears to be preferential fetal use of maternally ingested Fe derived from a dietary, animal-based heme source compared to Fe ingested as ferrous sulfate. Maternal serum hepcidin and maternal/neonatal Fe status may play a role in placental uptake of dietary heme and nonheme Fe.     

Milk folate secretion is not impaired during iron deficiency in humans

The purpose of this study was to examine whether maternal iron and/or folate status influences human milk folate secretion and is responsible for growth faltering of Otomi infants in Capulhuac, Mexico. Breast-feeding mothers (n = 71) were randomized at 22 +/- 13 d (baseline) postpartum to receive a daily multivitamin supplement containing folic acid (400 microg) with and without iron (18 mg). Mothers provided blood and milk samples at baseline, and at 82 +/- 15 and 138 +/- 18 d postpartum. Iron supplementation significantly improved hematocrit and transferrin receptor concentrations but had no influence on maternal folate status or milk folate or iron concentrations. Forty-three percent of mothers (29/68) had low blood folate concentrations at baseline, whereas only 6% (4/66) had low blood folate concentrations at approximately 138 d postpartum. Milk folate concentrations did not differ between Fe-deficient and Fe-sufficient women and provided adequate levels of dietary folate by approximately 82 d postpartum. While milk iron concentrations were unrelated to maternal iron status, they decreased during lactation, and, by approximately 138 d, they provided only 55% of the current recommendation. In conclusion, milk folate concentrations appear to be well preserved during maternal iron deficiency; hence, faltering growth among infants in Capulhuac, Mexico is unlikely the result of reduced milk folate concentration secondary to maternal Fe deficiency. However, milk Fe concentrations showed a temporal decline. Whether the disjuncture between recommended and actual Fe intakes among infants born with low Fe reserves and weaned to foods low in bioavailable Fe has functional consequences is worthy of further investigation.     

Effect of time of initiation and dose of prenatal iron and folic acid supplementation on iron and folate nutriture of Korean women during pregnancy

BACKGROUND: In Korea, it is customary to prescribe iron and folic acid supplements to pregnant women after the 20th wk of gestation; however, little evidence exists to support this practice. OBJECTIVE: The objective was to determine the effects of time of initiation and dose of prenatal iron and folic acid supplementation on the iron and folate nutriture of Korean women during pregnancy. DESIGN: A total of 131 pregnant women were placed into 1 of 5 experimental groups, either the control group or 1 of 4 supplemented groups. The supplemented groups varied by time of initiation, which was either during the first trimester or at week 20 of gestation, and by dose of iron and folic acid supplements provided, which consisted of either 30 mg Fe plus 175 microg folic acid or 60 mg Fe plus 350 microg folic acid. All supplemented groups continued supplementation until delivery. RESULTS: Improvements in iron and folate nutriture were highly dependent on when the supplement program was initiated, but both supplement doses were equally effective. In contrast, the influence of folic acid supplementation on maternal folate status was not as pronounced as was the influence of iron supplementation on iron status. CONCLUSION: In pregnant Korean women, initiating iron and folic acid supplementation earlier during pregnancy may prevent the deterioration of iron and folate nutriture more than does increasing supplement doses in later stages of pregnancy.     

Maternal smoking is associated with decreased 5-methyltetrahydrofolate in cord plasma

BACKGROUND: Maternal-fetal folate transport via the placenta has been shown to be concentrative. Exposure to cigarette smoke is associated with decreased maternal folate status through altered dietary intakes and possibly through nondietary mechanisms such as increased folate turnover. The effect of maternal smoking on fetal folate status has not been documented. OBJECTIVE: The objective was to determine the effect of maternal smoking on plasma 5-methyltetrahydrofolic acid (5-MTHFA) concentrations in umbilical cord blood. DESIGN: African American women were recruited from an antenatal clinic in Detroit, MI. Plasma 5-MTHFA concentrations were measured in maternal-umbilical cord pairings (n = 58). The participants completed a structured interview to determine demographic characteristics, including smoking. RESULTS: Concentrations of 5-MTHFA were significantly higher in venous cord plasma (16.8 +/- 7.5 ng/mL) than in maternal plasma (13.0 +/- 7.5 ng/mL) but remained associated (r = 0.60, P < 0.001) with each other. Cigarettes smoked by the mothers was negatively associated (r = -0.31, P = 0.019) with venous cord 5-MTHFA concentrations and remained so after control for maternal plasma 5-MTHFA and other variables. Venous cord plasma 5-MTHFA was significantly lower in smoking (15.1 +/- 7.6 ng/mL; n = 32) than in nonsmoking (19.0 +/- 7.0 ng/mL; n = 26) mothers. CONCLUSIONS: Cord plasma 5-MTHFA concentrations were elevated relative to maternal blood, as expected, because the placenta is capable of concentrative folate transport to the fetus. The negative effect of maternal smoking on infant, but not on maternal, 5-MTHFA status indicates that maternal smoking may impair folate transport to the fetus.     

Utilization of iron from an animal-based iron source is greater than that of ferrous sulfate in pregnant and nonpregnant women

Heme iron absorption during pregnancy and the role of hepcidin in regulating dietary heme iron absorption remains largely unexplored. The objective of this research was to examine relative differences in heme (animal based) and nonheme (ferrous sulfate) iron utilization. This study was undertaken in 18 pregnant (ages 16-32 y; wk 32-35 of gestation) and 11 nonpregnant women (ages 18-27 y). Women were randomly assigned to receive both an animal-based heme meal (intrinsically labeled (58)Fe pork) and labeled ferrous sulfate ((57)Fe) fed on alternate days. Blood samples obtained 2 wk postdosing were used to assess iron status indicators and serum hepcidin and iron utilization based on RBC incorporation of iron isotopes. Heme iron utilization was significantly greater than nonheme iron utilization in the pregnant (47.7 ± 14.4 vs. 40.4 ± 13.2%) and nonpregnant women (50.1 ± 14.8 vs. 15.3 ± 9.7%). Among pregnant women, utilization of nonheme iron was associated with iron status, as assessed by the serum transferrin receptor concentration (P = 0.003; r(2) = 0.43). In contrast, heme iron utilization was not influenced by maternal iron status. In the group as a whole, women with undetectable serum hepcidin had greater nonheme iron utilization compared with women with detectable serum hepcidin (P = 0.02; n = 29); however, there were no significant differences in heme iron utilization. Our study suggests that iron utilization from an animal-based food provides a highly bioavailable source of dietary iron for pregnant and nonpregnant women that is not as sensitive to hepcidin concentrations or iron stores compared with ferrous sulfate.     

Prepregnancy body mass index and dietary intake in the first trimester of pregnancy

OBJECTIVES: Adequate maternal nutrition is of paramount importance in pregnancy, particularly in the first trimester when fetal development is crucial. It has been reported that heavier women are most likely to fear weight gain associated with pregnancy. Few studies have, however, investigated associations between prepregnancy body mass index (BMI) and nutrient intakes in the first trimester of gestation using detailed, prospective methodologies. The aim of this study was to investigate possible associations between prepregnancy BMI and nutrient intakes in the first trimester of gestation. DESIGN: Seventy-two Caucasian, primiparous nonsmokers of mean age 33.1 years (SD 4.6) were recruited from three London teaching hospitals and they completed a background information questionnaire and a 4- to 7-day weighed inventory food diary during the first trimester of pregnancy. Prepregnancy anthropometric data were extracted from General Practitioner records. RESULTS: Prepregnancy BMI was inversely associated with dietary energy (P = 0.04), Southgate and Englyst fibre (P < 0.01), and iron and folate (P < 0.01). After excluding under-reporters [individual energy intake:basal metabolic rate (estimated) ratio < 1.2], prepregnancy BMI was inversely associated with folate intake (P =0.04). Dietary intakes of Englyst fibre (P = 0.03) were statistically significantly lower than average dietary recommendations in this group. CONCLUSIONS: This study identified that women with a high prepregnancy BMI are more likely to under-report nutrient intakes. The finding that folate intake was significantly lower in heavier women accurately reporting dietary intake is of particular concern.     

Iron deficiency, but not anemia, upregulates iron absorption in breast-fed peruvian infants

Iron absorption in adults is regulated by homeostatic mechanisms that decrease absorption when iron status is high. There are few data, however, regarding the existence of a similar homeostatic regulation in infants. We studied 2 groups of human milk-fed infants using (57)Fe (given as ferrous sulfate without any milk) and (58)Fe (given at the time of a breast-milk feeding) stable isotopes to determine whether healthy infants at risk for iron deficiency would regulate their iron absorption based on their iron status. We studied 20 Peruvian infants at 5-6 mo of age and 18 infants at 9-10 mo of age. We found no effect of infant hemoglobin concentration on iron absorption with 5-6 mo-old infants absorbing 19.2 +/- 2.1% and 9- to 10-mo-old infants absorbing 25.8 +/- 2.6% of the (57)Fe dose. For (58)Fe, 5- to 6-mo-old infants absorbed 42.6 +/- 5.0% and 9 to 10-mo-old infants absorbed 51.9 +/- 10.3%. Following log transformation, iron absorption from (57)Fe (r = -0.61, P = < 0.001) and (58)Fe (r = -0.61, P = < 0.001) were inversely correlated to serum ferritin (S-Ft). For both the (57)Fe and (58)Fe doses, infants with S-Ft <12 mg/L (n = 11) had significantly higher iron absorption than those with S-Ft >12 mg/L. We concluded that iron absorption in infants is related to iron status as assessed by serum ferritin but not hemoglobin concentration. Infants with low iron status upregulate iron absorption from breast milk at both 5-6 and 9-10 mo of age.     

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.     

Vitamin A and iron status are improved by vitamin A and iron supplementation in pregnant Indonesian women

In Indonesia, deficiencies of vitamin A and iron are of public health concern during pregnancy. We sought to determine the effects of vitamin A and iron supplementation on the vitamin A and iron status of pregnant Indonesian women. The women (n = 27) were randomly assigned to four groups. The modified relative dose response (MRDR) test for vitamin A status and hemoglobin, hematocrit and ferritin values were determined at baseline. Thereafter, daily supplements were administered: placebo [Pl] (n = 7), 8.4 micromol vitamin A [A] (n = 7), 1.07 mmol iron [Fe] (n = 5), and 8.4 micromol vitamin A plus 1.07 mmol iron [A + Fe] (n = 8). Post-treatment tests were performed after 8 wk. The MRDR value was reduced, i.e., vitamin A status improved, more markedly by the combination of vitamin A and iron than by either nutrient alone (P = 0.034). The decrease in the MRDR relative to baseline was significant in the A + Fe group (P = 0.008). Iron status was also significantly improved in these women (P < 0.05) with both iron and vitamin A supplementation. The mechanism of the enhancing effect of iron on the vitamin A-induced reduction in the MRDR is not known.     

Diet-induced iron deficiency anemia and pregnancy outcome in rhesus monkeys

BACKGROUND: Iron deficiency anemia (IDA) is relatively common in the third trimester of pregnancy, but causal associations with low birth weight and compromised neonatal iron status are difficult to establish in human populations. OBJECTIVE: The objective was to determine the effects of diet-induced IDA on intrauterine growth and neonatal iron status in an appropriate animal model for third-trimester IDA in women. DESIGN: Hematologic and iron-status measures, pregnancy outcomes, and fetal and neonatal evaluations were compared between pregnant rhesus monkeys (n = 14) fed a diet containing 10 microg Fe/g diet from the time of pregnancy detection (gestation days 28-30) and controls (n = 24) fed 100 microg Fe/g diet. RESULTS: By the third trimester, 79% of the iron-deprived dams and 29% of the control monkeys had a hemoglobin concentration <11 g/dL. There were also significant group differences in hematocrit, mean corpuscular volume, transferrin saturation, serum ferritin, and serum iron. At birth, the newborns of monkeys iron-deprived during pregnancy had significantly lower hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin values and a lower ratio of erythroid to total colony-forming units in bone marrow than did the control newborns. Pregnancy weight gain did not differ significantly between the iron-deprived and control dams, and the fetuses and newborns of the iron-deprived dams were not growth retarded relative to the controls. Gestation length, the number of stillbirths, and neonatal neurobehavioral test scores did not differ significantly by diet group. CONCLUSION: These data indicate that an inadequate intake of iron from the diet during pregnancy in rhesus monkeys can lead to compromised hematologic status of the neonate without indications of growth retardation or impaired neurologic function at birth.     

Weekly vitamin A and iron supplementation during pregnancy increases vitamin A concentration of breast milk but not iron status in Indonesian lactating women

Studies on the effect of vitamin A and iron supplementation during pregnancy on maternal iron and vitamin A status postpartum are scarce. We investigated whether retinol and iron variables in breast milk and in serum postpartum were enhanced more with weekly vitamin A and iron supplementation during pregnancy than with weekly iron supplementation. During pregnancy, subjects were randomly allocated to two groups and received either (n = 88) a weekly supplement of iron (120 mg Fe as FeSO(4)) and folic acid (500 microg) or (n = 82) the same amount of iron and folic acid plus vitamin A [4800 retinol equivalents (RE)]. Transitional milk (4-7 d postpartum) had higher (P < 0.001) concentrations of retinol and iron than mature milk (3 mo postpartum). Compared with the weekly iron group, the weekly vitamin A and iron group had a greater (P < 0.05) concentration of retinol in transitional milk (as micromol/L) and in mature milk (as micromol/g fat). Although serum retinol concentrations approximately 4 mo postpartum did not differ significantly, the weekly vitamin A and iron group had significantly fewer (P < 0.01) subjects with serum retinol concentrations < or = 0.70 micromol/L than the weekly iron group. Iron status and concentrations of iron in transitional and mature milk did not differ between groups. We have shown that weekly vitamin A and iron supplementation during pregnancy enhanced concentrations of retinol in breast milk although not in serum by approximately 4 mo postpartum. However, no positive effects were observed on iron status and iron concentration in breast milk.     

Multivitamin-mineral supplementation is not as efficacious as is iron supplementation in improving hemoglobin concentrations in nonpregnant anemic women living in Mexico

BACKGROUND: Iron supplements improve hemoglobin status and reduce anemia due to iron deficiency. It is not known whether multiple micronutrient (MM) supplements are as efficacious as are iron supplements alone in improving hemoglobin concentrations. OBJECTIVE: We conducted a randomized, double-blind community trial in Mexico to compare the efficacy of MM supplements containing iron with that of iron alone in improving hemoglobin concentrations in nonpregnant women. DESIGN: Nonpregnant women (n = 158) were recruited from a semirural community in Mexico and were randomly assigned to receive iron alone (60 mg; Fe group) or MM supplements (vitamins A, B complex, C, D, E, and K and iron, zinc, and magnesium; MM group) 6 d/wk in their home for 12 wk. Hemoglobin concentrations were measured in capillary blood samples at baseline and follow-up. RESULTS: The treatment groups (MM: n = 75; Fe: n = 77) did not differ significantly at recruitment in age, schooling, literacy, or socioeconomic status. There were no significant differences between groups in compliance (median: 97.5%), baseline hemoglobin concentrations, or prevalence of anemia (20%). Losses to follow-up (4%) and mean (+/-SD) changes in hemoglobin (MM group: 6.7 +/- 10.6 g/L; Fe group: 7.1 +/- 13.6 g/L) were not significantly different between groups. However, the change in hemoglobin in anemic subjects was greater in the Fe group than in the MM group (P < 0.05 for interaction), and there was no significant difference in nonanemic subjects. CONCLUSIONS: MM supplements may not be as efficacious as is iron alone in improving the hemoglobin status of anemic women.     

妊娠中期母亲铁营养与3~5月龄婴儿缺铁性贫血关系的研究

目的 研究孕中期母亲铁营养状况与3~5月龄婴儿缺铁性贫血(iron-deficiency anemia,IDA)的关系,为预防儿童IDA的发生提供科学依据。方法 测定妊娠中期母亲和脐带血血清铁蛋白(serum ferritin,SF)和血常规,随访至婴儿3~5月龄,测定婴儿血常规,对血红蛋白(hemoglobin,Hb)低于105 g/L的婴儿采集静脉血测定SF。比较妊娠中期母亲铁营养状况、脐带血SF和3～5月龄婴儿IDA的关系。结果 1) 3~5月婴儿IDA的发生率在孕中期铁缺乏组和正常组分别是12.9%和1.5%(χ²=4.62,P<0.05);2) 脐带血SF<75μg/L的发生率在孕中期铁缺乏组和正常组分别是25.8%和4.6%(χ²=9.6,P<0.05);3)3~5月龄婴儿IDA的发生率在脐带血SF<75 μg/L组是31.6%,脐带血SF≥75 μg/L组是2.8%(χ²=16.21,P<0.01)。结论 妊娠中期母亲轻度缺铁可减少胎儿期铁贮备,与早期婴儿IDA呈正相关。     

Milk folate but not milk iron concentrations may be inadequate for some infants in a rural farming community in San Mateo, Capulhuac, Mexico

BACKGROUND: We were interested in identifying possible nutritional reasons for growth faltering among breastfed infants in the rural farming community of San Mateo, Capulhuac, Mexico (2800 m above sea level). OBJECTIVE: We examined the prevalence of inadequate iron and folate status among lactating Otomi women and determined to what extent their iron and folate nutriture influenced the milk concentrations of these nutrients. DESIGN: Lactating women (n = 71) provided blood and milk samples and dietary information at a mean (+/- SD) of 22 +/- 13 d postpartum. Blood indexes included hemoglobin, hematocrit, serum iron, total-iron-binding capacity, ferritin, transferrin receptor, mean cell volume, plasma folate, and erythrocyte folate. RESULTS: Approximately 62% and 58% of the women had nutritional anemia defined as a hemoglobin concentration 相似文献   

Effect of high-dose iron supplements on fractional zinc absorption and status in pregnant women

BACKGROUND: Women have an increased risk of iron deficiency during pregnancy because of the demands of the developing fetus. Iron supplements are commonly advocated as a prophylactic treatment and are generally taken with meals to reduce side effects, but iron can interfere with the absorption of zinc. OBJECTIVE: The aim was to determine the effect of consuming an iron supplement (100 mg Fe/d as ferrous gluconate) with meals from 16 wk gestation to term on zinc status and absorption. DESIGN: Stable-isotope techniques were used to measure zinc status (exchangeable zinc pool, EZP) and fractional zinc absorption (FZA) in early and late pregnancy from a meal consumed at a different time from that of iron supplement or placebo consumption in 6 women given iron supplements and 7 given a placebo. RESULTS: FZA increased during pregnancy, independent of iron supplementation. FZA was significantly higher (P < 0.001) at week 34 than at weeks 16 and 24, and urinary zinc excretion was higher at week 34 than at week 16 (P = 0.02). The size of the EZP remained unchanged throughout pregnancy and was unaffected by iron supplementation. The iron status of iron-supplemented women was higher than that of the placebo group. CONCLUSIONS: In iron-replete pregnant women who consumed a Western diet, no detectable adverse effects on zinc metabolism were observed after ingestion of 100 mg Fe/d. An increase in the efficiency of zinc absorption was observed during late pregnancy.     

Dietary folate intake during pregnancy and birth weight in Japan

BACKGROUND: Inadequate folate status has been associated with many negative reproductive outcomes, such as neural tube defects (NTD), low birth weight and placental abruption. AIM OF THE STUDY: The objectives of this study were to evaluate the levels of dietary folate intake during pregnancy in Japanese women and the subsequent birth weight of their babies. METHODS: A longitudinal prospective study was conducted with 197 women with a singleton pregnancy in 2005. Dietary folate was investigated 3 times: in the first trimester at 12 weeks, in the second trimester at 20 weeks and in third trimester at 32 weeks using a diet history questionnaire (DHQ). Non fasting blood samples were collected from the women for measurement of homocysteine, hemoglobin, ferritin, unbound iron-binding capacity (UIBC) and total iron-binding capacity (TIBC). RESULTS: Energy intake increased as pregnancy advanced, but not significantly. The daily intake of folate increased from 248.5 +/- 113.1 microg/d in the first trimester to 275.4 +/- 100.2 microg/d in the third trimester (P = 0.04). This was well below the recommended level of 440 microg/d and only 10% of mothers were above the levels. In the third trimester, plasma homocysteine concentration was significantly higher in the low folate group of less than 250 microg/d (P = 0.02), but not the first and second trimesters. Dietary folate intake and plasma homocysteine concentrations were not likely to be predictors of birth weight in our subjects. CONCLUSIONS: Our study shows that Japanese women's energy and folate intakes do not meet their energy needs during pregnancy and are at an extremely low recommended dietary allowance level throughout pregnancy.