The efficacy of a local ascorbic acid-rich food in improving iron absorption from Mexican diets: a field study using stable isotopes

BACKGROUND: One potentially sustainable approach to improving iron status at the community level is to encourage the consumption of local ascorbic acid-rich foods, in conjunction with meals high in nonheme iron. OBJECTIVE: The study, conducted in rural Mexico, measured stable isotopes of iron to evaluate the effect on iron absorption of the addition of 25 mg ascorbic acid as agua de limón (limeade) to 2 typical meals per day for 2 wk. DESIGN: Fifteen nonpregnant, nonlactating, iron-deficient (ferritin < 12 microg/L) women (x +/- SD age: 28.3 +/- 7.7 y) fasted overnight and were brought to a community clinic. After an initial blood sample, subjects consumed 0.25 mg (57)Fe with both breakfast and lunch for 14 d. On day 29, another blood sample was taken, and a reference dose of 2.7 mg (58)Fe with 25 mg ascorbic acid was given. For the following 15 d, participants consumed 0.25 mg (57)Fe added to both breakfast and lunch with 25 mg ascorbic acid added to each meal as limeade. A final blood sample was taken on day 59. RESULTS: Iron absorption was calculated from recovery of isotopes in blood obtained 14 d after administration of each isotope. When 25 mg ascorbic acid as limeade was added to test meals twice a day for 2 wk, iron absorption increased significantly (P < 0.001) in every subject: the mean absorption rose from 6.6 +/- 3.0% to 22.9 +/- 12.6%. CONCLUSIONS: The consumption of 25 mg ascorbic acid as limeade twice daily with meals substantially improved iron absorption and may improve the iron status of nonpregnant, nonlactating, iron-deficient women.     

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.     

Iron absorption from soybean ferritin in nonanemic women

BACKGROUND: Dietary ferritin, a protein cage around an iron mineral, is an underestimated source of bioavailable iron. Plant ferritin, the most common dietary ferritin, has not been studied. Iron from animal ferritin is absorbed as well as is iron from FeSO4 in women. OBJECTIVE: The objective was to examine iron absorption from purified soybean ferritin. DESIGN: Healthy, nonanemic women (n = 16) were fed a standardized meal (bagel, cream cheese, and apple juice) containing 1 microCi 59Fe/meal as FeSO4 or (extrinsically labeled) as iron-free soybean ferritin reconstituted with the high phosphate characteristic of plant ferritin (iron:phosphorus = 4:1). Iron-free, apo-soybean ferritin was prepared (with the use of thioglycolic acid and extensive dialysis) from purified ferritin. In a randomized crossover design, the other labeled meal, which contained FeSO4 or ferritin, was given after 4 wk. The subjects received 140 microg Fe as ferritin (2.5 mg) or as FeSO4. After 28 d, whole-body 59Fe and 59Fe in red blood cells were measured before and after dosing. RESULTS: There was no significant difference in whole-body iron absorption from soybean ferritin (29.9 +/- 19.8%) and that from FeSO4 (34.3 +/- 23.6%) or in iron absorption calculated from red blood cell incorporation (33.0 +/- 20.1% for soybean ferritin and 35.3 +/- 23.4% for FeSO4), which confirmed previous results with animal ferritin that was mineralized and labeled similarly. An inverse relation was observed between serum ferritin and iron absorption from both ferritin and FeSO4, which suggested that sensors regulating iron absorption respond similarly to iron provided as ferrous salts or as ferritin mineral. CONCLUSION: Iron from soybean ferritin is well absorbed and may provide a model for novel, utilizable, plant-based forms of iron for populations with a low iron status.     

Iron absorption by healthy women is not associated with either serum or urinary prohepcidin

BACKGROUND: Although hepcidin is proposed as a regulator of iron absorption, this has not been assessed in humans. OBJECTIVE: Our objective was to assess the relation between serum or urinary prohepcidin and iron absorption in healthy premenopausal women. DESIGN: The subjects were 28 healthy women aged 22-51 y with normal hemoglobin concentrations (120-152 g/L). Absorption of 0.5 mg Fe with 0.2 microCi 59Fe tracer, both as FeSO4, was measured by whole-body scintillation counting 13 d after oral administration. Fasting blood and urine samples were collected the day of and 16 wk after the absorption measurement. Serum and urinary prohepcidin concentrations were measured by an enzyme-linked immunosorbent assay by using an antibody against amino acid residues 28-47 of the proregion. RESULTS: Mean (+/-SD) iron absorption was 36 +/- 19% (range: 4-81%), and serum ferritin (geometric x) was 27 microg/L (range: 4-122 microg/L), as commonly observed in healthy premenopausal women. Serum prohepcidin was 196 microg/L (range: 99-376 microg/L) and, in contrast with urinary prohepcidin, was relatively consistent for the women between 0 and 16 wk. Serum prohepcidin correlated directly with serum ferritin (R2 = 0.28, P < 0.01) but was unrelated to 59Fe absorption, in contrast to serum ferritin (R2 = 0.33, P < 0.01). CONCLUSIONS: Serum prohepcidin concentrations were relatively stable within subjects and correlated with serum ferritin. However, unlike serum ferritin, neither serum nor urinary prohepcidin concentrations were related to iron absorption in healthy women.     

Diet and iron status of nonpregnant women in rural Central Mexico

BACKGROUND: Few studies have examined the relation of iron status to diet in populations from developing countries with high levels of iron deficiency and diets of poor quality. OBJECTIVE: The objective was to identify nutrients, dietary constituents, and foods that are associated with better iron status in a rural Mexican population. DESIGN: A prospective cohort study was conducted in rural central Mexico. The subjects were 125 nonpregnant women aged 16-44 y. During the 12 mo before blood collection, food intakes were assessed repeatedly by a combination of dietary recalls, food weighing, and food diaries [mean (+/-SD) days of food intake data: 18.8 +/- 5.9 d]. Hemoglobin, hematocrit, and plasma ferritin were measured at the end of the study. RESULTS: Higher plasma ferritin concentrations were associated with greater intakes of nonheme iron and ascorbic acid after control for age, BMI, breast-feeding, season, and the time since the birth of the last child. Higher ascorbic acid intakes, but not higher intakes of heme and nonheme iron, predicted a lower risk of low hemoglobin and hematocrit values after control for the background variables. Consumption of the alcoholic beverage pulque predicted a lower risk of low ferritin and low hemoglobin values. Seasonal variation in ferritin, hemoglobin, and hematocrit values was observed. CONCLUSION: Better iron status was associated with greater intakes of foods containing nonheme iron and ascorbic acid. PULQUE:a beverage containing iron, ascorbic acid, and alcohol-may influence the iron status of women in rural central Mexico.     

Maternal iron status influences iron transfer to the fetus during the third trimester of pregnancy

BACKGROUND: The effect of maternal iron status on fetal iron deposition is uncertain. OBJECTIVE: We used a unique stable-isotope technique to assess iron transfer to the fetus in relation to maternal iron status. DESIGN: The study group comprised 41 Peruvian women. Of these women, 26 received daily prenatal supplements containing iron and folate (n = 11; Fe group) or iron, folate, and zinc (n = 15; Fe+Zn group) from week 10-24 of pregnancy to 1 mo postpartum. The remaining 15 women (control group) received iron supplementation only during the final month of pregnancy. During the third trimester of pregnancy (+/- SD: 32.9 +/- 1.4 wk gestation) oral 57Fe (10 mg) and intravenous 58Fe (0.6 mg) stable iron isotopes were administered to the women, and isotope enrichment and iron-status indicators were measured in cord blood at delivery. RESULTS: The net amount of 57Fe in the neonates' circulation (from maternal oral dosing) was significantly related to maternal iron absorption (P < 0.005) and inversely related to maternal iron status during the third trimester of pregnancy: serum ferritin (P < 0.0001), serum folate (P < 0.005), and serum transferrin receptors (P < 0.02). Significantly more 57Fe was transferred to the neonates in non-iron-supplemented women: 0.112 +/- 0.031 compared with 0.078 +/- 0.042 mg in the control group (n = 15) and the Fe and Fe+Zn groups (n = 24), respectively (P < 0.01). In contrast, 58Fe tracer in the neonates' circulation was not significantly related to maternal iron status. CONCLUSION: The transfer of dietary iron to the fetus is regulated in response to maternal iron status at the level of the gut.     

Marginal iron deficiency without anemia impairs aerobic adaptation among previously untrained women

BACKGROUND: Iron deficiency without anemia has been shown to reduce both muscle-tissue oxidative capacity and endurance in animals. However, the consequences of iron deficiency in humans remain unclear. OBJECTIVE: We investigated the effects of iron supplementation on adaptation to aerobic training among marginally iron-depleted women. We hypothesized that iron supplementation for 6 wk would significantly improve iron status and maximal oxygen uptake (VO(2)max) after 4 wk of concurrent aerobic training. DESIGN: Forty-one untrained, iron-depleted, nonanemic women were randomly assigned to receive either 50 mg FeSO(4) or a placebo twice daily for 6 wk in a double-blind trial. All subjects trained on cycle ergometers 5 d/wk for 4 wk, beginning on week 3 of the study. RESULTS: Six weeks of iron supplementation significantly improved serum ferritin and serum transferrin receptor (sTfR) concentrations and transferrin saturation without affecting hemoglobin concentrations or hematocrit. Average VO(2)max and maximal respiratory exchange ratio improved in both the placebo and iron groups after training; however, the iron group experienced significantly greater improvements in VO(2)max. Both iron-status and fitness outcomes were analyzed after stratifying by baseline sTfR concentration (> and < or = 8.0 mg/L), which showed that the previously observed treatment effects were due to iron-status and fitness improvements among subjects with poor baseline iron status. CONCLUSIONS: Our findings strongly suggest that iron deficiency without anemia but with elevated sTfR status impairs aerobic adaptation among previously untrained women and that this can be corrected with iron supplementation.     

Nonheme-iron absorption, fecal ferritin excretion, and blood indexes of iron status in women consuming controlled lactoovovegetarian diets for 8 wk

BACKGROUND: The characteristics of vegetarian diets suggest that these diets would have lower dietary iron bioavailability than nonvegetarian diets, but there is no evidence of iron deficiency in vegetarians. OBJECTIVE: We evaluated the responsiveness of serum and fecal ferritin to differences in iron absorption from controlled lactoovovegetarian and nonvegetarian diets. DESIGN: Twenty-one women aged 20-42 y with serum ferritin concentrations from 6 to 149 microg/L consumed lactoovovegetarian and nonvegetarian weighed diets for 8 wk each (crossover design). The diets differed substantially in meat and phytic acid contents. Nonheme-iron absorption was measured from the whole diets after 4 wk by using extrinsic 59Fe and whole-body counting. Ferritin in extracts of fecal composites and in serum was measured by enzyme-linked immunosorbent assay the last 2 wk of each diet. RESULTS: Nonheme-iron absorption was less from the lactoovovegetarian diet than from the nonvegetarian diet (1.1% compared with 3.8%; P < 0.01; n = 10). Diet did not affect hemoglobin, transferrin saturation, erythrocyte protoporphyrin, or serum ferritin. Substantially less fecal ferritin was excreted with the lactoovovegetarian diet than with the nonvegetarian diet (1.1 compared with 6.0 microg/d, respectively; P < 0.01; n = 21). CONCLUSIONS: This research indicates 1) 70% lower nonheme-iron absorption from a lactoovovegetarian diet than from a nonvegetarian diet; 2) an associated decrease in fecal ferritin excretion, suggesting partial physiologic adaptation to increase the efficiency of iron absorption; and 3) an insensitivity of blood iron indexes, including serum ferritin, to substantial differences in dietary iron absorption for 8 wk.     

Comparison of the efficacy of wheat-based snacks fortified with ferrous sulfate, electrolytic iron, or hydrogen-reduced elemental iron: randomized, double-blind, controlled trial in Thai women

BACKGROUND: Although elemental iron powders are widely used to fortify cereal products, little data exist on their efficacy in humans. OBJECTIVE: We compared the efficacy of wheat-based snacks fortified with ferrous sulfate, electrolytic iron, or hydrogen-reduced iron in Thai women with low iron stores. DESIGN: A double-blind intervention was conducted in 18-50-y-old women (n = 330) randomly assigned into 4 groups to receive either no fortification iron or 12 mg Fe/d for 6 d/wk for 35 wk as ferrous sulfate, electrolytic iron, or hydrogen-reduced iron in a baked, wheat-flour-based snack. Snacks were not consumed with meals, and consumption was monitored. At baseline, 20 wk, and 35 wk, hemoglobin status and iron were measured and the groups were compared. RESULTS: Between baseline and 35 wk, geometric mean serum ferritin (SF) increased significantly in all 3 groups receiving iron (P < 0.01), and geometric mean serum transferrin receptor (TfR) decreased significantly in the groups receiving ferrous sulfate and electrolytic iron (P < 0.05). Calculated mean (+/-SD) body iron stores increased from 1.5 +/- 2.8 to 5.4 +/- 2.9 mg/kg in the ferrous sulfate group, from 1.5 +/- 3.5 to 4.4 +/- 3.6 mg/kg in the electrolytic iron group, and from 1.3 +/- 3.2 to 3.2 +/- 4.3 mg/kg in the hydrogen-reduced iron group (P < 0.01 for all 3 groups) but did not change significantly in the control group. CONCLUSIONS: Ferrous sulfate, electrolytic iron, and hydrogen-reduced iron, fortified into wheat-based snacks, significantly improved iron status. On the basis of the change in body iron stores during the 35-wk study, the relative efficacy of the electrolytic and hydrogen-reduced iron compared with ferrous sulfate was 77% and 49%, respectively.     

Response of hemoglobin, serum ferritin, and serum transferrin receptor during iron supplementation in pregnancy: a prospective study

OBJECTIVE: We evaluated the effect of iron supplementation on biochemical indicators of iron status, namely hemoglobin (Hb), serum ferritin (SF), and serum transferrin receptor (sTfR), during pregnancy. METHODS: A prospective study was conducted in 73 pregnant women who received daily supplements of 60 mg of iron and 500 microg of folic acid for 100 d from 19 wk of gestation. The indicators of iron status (Hb, SF, and sTfR) at 19, 27, and 35 wk of gestation were analyzed. The response of iron status indicators to iron supplementation was assessed in the cohort and in pregnant women who were anemic (n = 35) and non-anemic (n = 38) at 19 wk. RESULTS: All three indicators of iron status during supplementation (27 and 35 wk) were similar to the presupplementation status. The sTfR as an indicator correlated negatively with presupplementation Hb levels (r = -0.417). Based on sTfR level in iron-adequate pregnant women, a cutoff value of at least 12.0 mg/L was derived to define iron deficiency in pregnancy. When the response was tested in anemic pregnant women, iron supplementation improved mean Hb (P < 0.05) at the end of 35 wk (96 +/- 8.8 to 110 +/- 20.2 g/L) of gestation, with no change in SF. Conversely, non-anemic pregnant women showed a significant increase in SF and a decrease in Hb (122 +/- 11.6 to 112 +/- 15.2 g/L) at 35 wk of gestation. A significant effect of iron intake on sTfR was seen only among iron-deficient anemic women. CONCLUSIONS: These observations suggest that, during pregnancy, sTfR responds to iron supplementation when there is iron-deficiency anemia and therefore can be used as an indicator.     

Effects of different calcium sources on iron absorption in postmenopausal women

We measured the effect of calcium from food and supplement sources on whole-body retention of 59Fe in 19 normal postmenopausal women. Each woman received a placebo and 500 mg calcium from a mixed calcium citrate-malate salt (CCM), from orange juice plus CCM, and from milk after a test breakfast meal to which 59Fe had been added. The test meal contained 238 mg calcium. Whole-body countings of 59Fe were performed before and 30 min and 2 wk after each test meal. Retention of 59Fe was 8.3 +/- 1.1% (means +/- SEM) with placebo, 3.4 +/- 0.78% with milk, 6.0 +/- 0.97% with CCM, and 7.4 +/- 1.7% with CCM plus orange juice. When compared with placebo, milk and CCM significantly lowered iron retention (p less than 0.05) whereas CCM plus orange juice did not. The reduction with milk was greater than that with CCM (p less than 0.05) or CCM plus orange juice (p less than 0.05). The differences in the effects of these calcium sources on 59Fe retention may result from their varied contents of citric and ascorbic acids, known enhancers of iron absorption.     

Dietary treatment of iron deficiency in women of childbearing age.

BACKGROUND: The Australian Iron Status Advisory Panel advocates dietary intervention as the first treatment option for mild iron deficiency [serum ferritin (SF) = 10-15 microg/L]. However, there appear to be no studies on the efficacy of dietary treatment for iron deficiency. OBJECTIVE: We compared the effects of iron supplementation and of a high-iron diet on serum ferritin (SF) and hemoglobin in iron-deficient women of childbearing age. DESIGN: Forty-four iron-deficient women (SF <15 microg/L or SF = 15-20 microg/L plus serum iron <10 micromol/L and total-iron-binding capacity >68 micromol/L) and 22 iron-replete women (hemoglobin > or =120 g/L and SF >20 microg/L) matched for age and parity categories were enrolled and completed 7-d weighed food records at baseline. The iron-deficient women were randomly allocated to receive iron supplementation (105 mg/d; supplement group) or a high-iron diet (recommended intake of absorbable iron: 2.25 mg/d; diet group) for 12 wk. Hematologic and dietary assessments were repeated at the end of the intervention and again after a 6-mo follow-up. RESULTS: Mean SF in the supplement group increased from 9.0 +/- 3.9 microg/L at baseline to 24.8 +/- 10.0 microg/L after the intervention and remained stable during follow-up (24.2 +/- 9.8 microg/L), whereas the diet group had smaller increases during the intervention (8.9 +/- 3.1 to 11.0 +/- 5.9 microg/L) but continued to improve during follow-up (to 15.2 +/- 9.5 microg/L). Mean hemoglobin tended to improve in both intervention groups, but the change was only significant in the supplement group. CONCLUSIONS: In iron-deficient women of childbearing age, a high-iron diet produced smaller increases in SF than did iron supplementation but resulted in continued improvements in iron status during a 6-mo. follow-up.     

Iron supplementation during pregnancy, anemia, and birth weight: a randomized controlled trial

BACKGROUND: The need for prophylactic iron during pregnancy is uncertain. OBJECTIVE: We tested the hypothesis that administration of a daily iron supplement from enrollment to 28 wk of gestation to initially iron-replete, nonanemic pregnant women would reduce the prevalence of anemia at 28 wk and increase birth weight. DESIGN: Between June 1995 and September 1998, 513 low-income pregnant women in Cleveland were enrolled in the study before 20 wk of gestation. Of these, 275 had a hemoglobin concentration >/= 110 g/L and a ferritin concentration >/= 20 micro g/L and were randomly assigned to receive a monthly supply of capsules containing either 30 mg Fe as ferrous sulfate or placebo until 28 wk of gestation. At 28 and 38 wk of gestation, women with a ferritin concentration of 12 to < 20 micro g/L or < 12 micro g/L received 30 and 60 mg Fe/d, respectively, regardless of initial assignment. Almost all the women received some supplemental iron during pregnancy. We obtained infant birth weight and gestational age at delivery for 117 and 96 of the 146 and 129 women randomly assigned to receive iron and placebo, respectively. RESULTS: Compared with placebo, iron supplementation from enrollment to 28 wk of gestation did not significantly affect the overall prevalence of anemia or the incidence of preterm births but led to a significantly higher mean (+/- SD) birth weight (206 +/- 565 g; P = 0.010), a significantly lower incidence of low-birth-weight infants (4% compared with 17%; P = 0.003), and a significantly lower incidence of preterm low-birth-weight infants (3% compared with 10%; P = 0.017). CONCLUSION: Prenatal prophylactic iron supplementation deserves further examination as a measure to improve birth weight and potentially reduce health care costs.     

Electrolytic iron or ferrous sulfate increase body iron in women with moderate to low iron stores

Commercial elemental iron powders (electrolytic and reduced iron), as well as heme iron supplements, were tested for efficacy in improving the iron status of women. In a randomized, double-blind trial, 51 women with moderate to low iron stores received daily for 12 wk: 1) placebo, 2) 5 mg iron as heme iron or 50 mg iron as 3) electrolytic iron, 4) reduced iron, or 5) FeSO(4). Treatments were provided in 2 capsules (heme carrier) and 3 wheat rolls (other iron sources). Differences in iron status, food nonheme iron absorption, and fecal properties were evaluated. Body iron, assessed from the serum transferrin receptor:ferritin ratio, increased significantly more in subjects administered FeSO(4) (127 +/- 29 mg; mean +/- SEM) and electrolytic (115 +/- 37 mg), but not the reduced (74 +/- 32 mg) or heme (65 +/- 26 mg) iron forms, compared with those given placebo (2 +/- 19 mg). Based on body iron determinations, retention of the added iron was estimated as 3.0, 2.7, 1.8, and 15.5%, in the 4 iron-treated groups, respectively. Iron treatments did not affect food iron absorption. The 50 mg/d iron treatments increased fecal iron and free radical-generating capacity in vitro, but did not affect fecal water cytotoxicity. In subjects administered FeSO(4), fecal water content was increased slightly but significantly more than in the placebo group. In conclusion, electrolytic iron was approximately 86% as efficacious as FeSO(4) for improving body iron, but the power of this study was insufficient to detect any efficacy of the reduced or heme iron within 12 wk. With modification, this methodology of testing higher levels of food fortification for several weeks in healthy women with low iron stores has the potential for economically assessing the efficiency of iron compounds to improve iron status.     

Dietary iron supplements and Moringa oleifera leaves influence the liver hepcidin messenger RNA expression and biochemical indices of iron status in rats

In this study, the effects of iron depletion and repletion on biochemical and molecular indices of iron status were investigated in growing male Wistar rats. We hypothesized that iron from Moringa leaves could overcome the effects of iron deficiency and modulate the expression of iron-responsive genes better than conventional iron supplements. Iron deficiency was induced by feeding rats an iron-deficient diet for 10 weeks, whereas control rats were maintained on an iron-sufficient diet (35.0-mg Fe/kg diet). After the depletion period, animals were repleted with different source of iron, in combination with ascorbic acid. Iron deficiency caused a significant (P < .05) decrease in serum iron and ferritin levels by 57% and 40%, respectively, as compared with nondepleted control animals. Significant changes in the expression (0.5- to100-fold) of liver hepcidin (HAMP), transferrin, transferrin receptor-2, hemochromatosis type 2, ferroportin 1, ceruloplasmin, and ferritin-H were recorded in iron-depleted and iron-repleted rats, as compared with nondepleted rats (P < .05). Dietary iron from Moringa leaf was found to be superior compared with ferric citrate in overcoming the effects of iron deficiency in rats. These results suggest that changes in the relative expression of liver hepcidin messenger RNA can be used as a sensitive molecular marker for iron deficiency.     

Intermittent iron supplementation regimens are able to maintain safe maternal hemoglobin concentrations during pregnancy in Venezuela

Daily iron supplementation programs for pregnant women recommend amounts of iron that are considered by some to be excessive, and either lower-dose or less frequent iron supplementation regimens have been proposed. A randomized, placebo-controlled study was performed to assess and compare the relative effectiveness of a weekly (WS) or twice weekly (TW) iron supplementation schedule in maintaining or achieving hemoglobin (Hb) levels at term considered to carry minimal maternal and fetal risk (90-130 g/L). Pregnant women (n = 116) at wk 10-30 of gestation (63 WS and 53 TW) were enrolled in the study (52 in WS and 44 TW completed the study). Women were randomly allocated to receive a 120-mg oral dose of iron as ferrous sulfate and 0.5 mg of folic acid weekly (n = 52) or 60 mg iron and 0.25 mg folic acid and a placebo twice weekly (n = 44). Hb, hematocrit, serum ferritin, and transferrin saturation were estimated at baseline and at 36-39 wk of gestation. Baseline dietary data and the presence and intensity of intestinal helminthic infections were assessed. The duration of supplementation was 14 +/- 4 wk and the median level of adherence was 60.5%. Hb concentrations improved in women following the TW regimen and in women following WS who had low baseline Hb levels. About 89% of WS women and 95% of TW women maintained Hb levels at term (between 90 g/L and 130 g/L), a range associated with optimal pregnancy outcomes. One woman in the TW group exhibited higher Hb levels that potentially carried perinatal risk (>130 g/L). Intermittent iron and folic acid supplementation may be a valid strategy when used as a preventive intervention in prenatal care settings.     

Daily iron supplementation is more effective than twice weekly iron supplementation in pregnant women in Pakistan in a randomized double-blind clinical trial

In the context of limited effectiveness of iron supplementation programs, intermittent iron supplementation is currently under debate as a possible alternative strategy that may enhance the effectiveness of operational programs. This field-based trial assessed the outcome of twice weekly iron supplementation compared to daily in Pakistan. A double-blind, randomized, clinical trial was conducted in Northern Pakistan. Anemic pregnant women (n = 191) were assigned to receive daily (200 mg ferrous sulfate) or twice weekly (2 x 200 mg ferrous sulfate) iron supplementation. Hemoglobin was measured at baseline and at 4-wk intervals for up to 12 wk. Serum ferritin was measured at baseline and 8 or 12 wk. Analysis was by intention to treat. The two groups did not differ in age, parity, sociodemographic characteristics, hemoglobin or serum ferritin concentrations at baseline. Women who received iron daily had a greater rise in hemoglobin compared with women who received iron twice weekly (17.8 +/- 1.8 vs. 3.8 +/- 1.2 g/L, P < 0.001). The serum ferritin concentrations increased by 17.7 +/- 3.9 microgram/L (P < 0.001) in the daily supplemented group and did not change in the twice weekly group. Daily iron supplementation remained superior to twice weekly supplementation after controlling initial hemoglobin Z-scores and duration of treatment. The body mass index (BMI) modified the effect of daily versus twice weekly iron supplementation. For every unit increase in BMI, the difference between the two treatment groups was reduced by 0.0014 (final hemoglobin Z-score; P = 0.027). We recommend continuation of daily iron supplementation as opposed to intermittent iron supplementation in pregnant women in developing countries.     

Zinc and iron nutrition in Chilean children fed fortified milk provided by the Complementary National Food Program

OBJECTIVE: Chilean infants are at risk for isolated zinc and iron deficiencies because of a low consumption of animal products in low socioeconomic sectors. In 1999, the National Complementary Food Program of Chile manufactured a new milk (2 kg of powdered milk/mo) fortified with iron (Fe; 10 mg/L), zinc (Zn; 5 mg/L), and copper (0.5 mg/L) to be provided to infants until age 18 mo and to pregnant women. We analyzed the nutrition status of zinc and iron at age 18 mo in infants who consumed the fortified cow's milk. METHODS: Forty-two healthy male children with normal growth and from lower socioeconomic groups were studied. A nutrition survey was conducted; blood and hair samples for Zn in plasma and hair, hemoglobin, hematocrit, and serum ferritin were obtained. RESULTS: Mean intakes were: energy, 106 +/- 27 kcal. kg(-1). d(-1); protein, 3.8 +/- 1.1 g. kg(-1). d(-1); Zn, 5.2 +/- 1.9 g/d (0.98 mg Zn/MJ; 68% of World Health Organization recommendations); Fe, 11.2 +/- 5.5 mg/d; and dietary fiber, 9.8 +/- 3.9 g/d. Plasma Zn in 54.8% of children was no greater than 12.3 microM/L; 36% had hair Zn level no greater than 1.23 microM/g and 39% had serum ferritin levels no greater than 10 microg/dL (12% were anemic). Hair Zn was correlated to socioeconomic level (Spearman's rank correlation, r = -0.53; P < 0.001) and plasma Zn was correlated to the z weight/length (r = 0.47; P < 0.05), subscapular skinfold (r = 0.46; P < 0.05), and Zn intake (r = 0.46; P < 0.05). CONCLUSIONS: The fortified powdered cow's milk provided to infants until age 18 mo by the Complementary Food Program in Chile favorably affects the Fe status of these children, but possibly not the Zn nutrition; we suggest re-evaluation of the levels of Zn fortification.     

补铁对人体血清转铁蛋白受体水平的影响

目的研究补铁过程血清转铁蛋白受体(sTfR)值的时相动态变化趋势,为sTfR是否可作为观察补铁效果的指标提供依据.方法 2002年4～10月,从河北省廊坊市和北京顺义区初筛942名18～45岁育龄妇女,检测其铁生化指标,依现行铁状况评价标准,筛检红细胞生成缺铁(IDE)和缺铁性贫血(IDA)妇女,经知情同意后,共有59名妇女完成了自始至终的补铁效果动态观察.采用L-苏糖酸亚铁胶囊(7 mg元素铁/粒),IDE妇女隔日服4粒,IDA妇女每日服4粒,补铁12周,分别测定补铁过程中0、3、6、9和12周的铁生化指标和sTfR值,观察sTfR时相动态变化.结果 IDE和IDA育龄妇女sTfR含量分别为(26.62±10.57)nmol/L和(41.25±21.96)nmol/L,均显著高于健康者的水平;在补铁过程中,sTfR呈现以下变化特点在IDE期,sTfR在补铁后3周内趋于平稳,3周后渐进性降低,至12周时接近和达到健康者的水平,检测值为(17.86±5.57)nmol/L;在IDA期,补铁后3周内sTfR迅速下降,3周后缓慢下降,至第9周趋于平稳,至12周时接近和达到健康者的水平,检测值为(19.54±5.94)nmol/L;sTfR/血清铁蛋白在补铁过程中的变化趋势与sTfR基本平行;补铁过程中sTfR与血红蛋白、血清铁蛋白呈负相关,与锌卟啉呈正相关.结论在补铁过程,sTfR随机体铁状况的恢复而逐渐下降至正常水平,sTfR可作为观察补铁效果的特异指标.     

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.