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.     

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.     

Obesity and iron status in menstruating women

The relationship between iron stores and obesity in menstruating women was studied in 20 obese and 20 nonobese women matched for age and contraception. Although no difference was observed in serum iron or total-iron-binding capacity, the obese group showed significantly higher hemoglobin (137 +/- 9 vs 10 g/L, mean +/- SD; P less than 0.01), hematocrit (0.41 +/- 0.02 vs 0.39 +/- 0.03, P less than 0.05), and serum ferritin concentrations (48.0 +/- 44.3 vs 25.8 +/- 19.5 micrograms/L, P less than 0.05). There was no difference between obese and nonobese women in either the menstrual-cycle interval or the duration of the menstrual flow. Iron intake was significantly higher in the obese group (15.9 +/- 2.9 vs 14.1 +/- 2.9 mg/d, P less than 0.05). These results suggest that obese menstruating women are at low risk of depleting iron stores, possibly because of high iron intake. Iron-fortification programs might thus be undesirable in such subjects.     

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.     

Effects of iron intake on iron stores in elderly men and women: longitudinal and cross-sectional results

OBJECTIVE: For middle aged and elderly subjects there is a concern that increased iron intake, especially heme iron associated with consumption of red meat, leads to increased iron stores resulting in disturbed glucose homeostasis and risk for cardiovascular disease and certain types of cancer. The aim of this study was to investigate the influence of heme, non-heme and iron supplementation on iron stores in healthy elderly men and women. METHOD: We conducted a 10 year longitudinal study (48 men and 77 women) and a one year cross-sectional study (165 men and 226 women) in healthy elderly men and women enrolled in the New Mexico Aging Process Study. Iron stores were estimated by serum ferritin concentrations and iron intake was determined by three-day food records in the longitudinal study and by a food frequency questionnaire in the cross-sectional study. RESULTS: We found no association between heme iron intake and iron stores in either the longitudinal or cross sectional study. In the cross-sectional study we found in women, but not in men, that age and supplemental iron intake were significantly and positively associated with increased iron stores. CONCLUSION: Iron stores in elderly men are thought to reach steady state levels where iron absorption is adjusted to a level just sufficient to cover basal iron losses. In elderly women, we speculate that not enough time has elapsed for postmenopausal women to reach steady state levels of iron stores resulting in increases in iron absorption with age. Another factor is that use of hormone replacement therapy could further delay some women in reaching steady state iron levels due to continued menstrual blood losses.     

Iron supplement use and iron status among US adults: results from the third National Health and Nutrition Examination Survey

BACKGROUND: Patients with hemochromatosis are instructed to avoid taking supplemental iron. Whether supplemental iron intakes lead to higher iron status among healthy persons remains less clear. OBJECTIVE: The objective was to ascertain whether supplemental iron intakes are associated with increases in iron transport (transferrin saturation) and stores (serum ferritin) among US adults aged > or = 19 y. DESIGN: We analyzed data for 5948 adults from whom a fasting serum sample was collected during the third National Health and Nutrition Examination Survey. We used multivariable linear regression and analysis of variance to assess the association of supplemental iron intake with iron transport and stores among men (aged 19-30 y or > 30 y) and women (nonpregnant premenopausal or postmenopausal); multiple comparison tests were also performed. RESULTS: Healthy adults who took supplements containing average daily amounts of iron at < or = 3 times the recommended dietary allowance (RDA) did not have significantly higher iron transport or stores than did those who did not take supplements. In younger men, the intake of > 32 mg Fe/d (> 4x RDA) was associated with mean transport iron concentrations that were significantly higher than those in persons who took 0 to < or = 24 mg Fe/d. In older men, the intake of > 32 mg Fe/d (> 4x RDA) was associated with mean iron stores that were significantly higher than those in persons who took 0 to < or = 24 mg Fe/d; a similar result was observed in postmenopausal women, but it was of borderline statistical significance. CONCLUSION: Supplement users should be made aware of the amount of iron necessary to satisfy dietary requirements and informed of the possible influence that excess iron intake can have on body iron stores and health.     

Available dietary iron intakes of a selected sample of pre- and postmenopausal canadian women

Available iron, total iron, heme and non-heme iron intakes of 100 premenopausal women (mean age±SD=30.3±6.1 years) and 96 postmenopausal women (mean age+SD=67.2±6.6 years) living in a University Community and consuming self-selected diets, were calculated from three day dietary record data. Dietary iron levels were also determined by instrumental neutron activation analysis of one day food composites collected by the subjects. No significant differences were observed between the total dietary iron, heme and non-heme iron intakes of the two groups. Calculated mean dietary iron levels were 12.09±3.52 and 11.75±3.24 mg per day for the pre- and postmenopausal women, respectively. Highly significant positive correlations (p<0.001) were noted between the nalyzed intakes of iron and those calculated from the corresponding record day. Mean daily available iron intakes calculated using Monsen et al's model assuming 500 mg iron stores for the pre-and post menopausal women were: ?0.92±0.34 mg and 0.88±0.31 mg respectively; and 1.28±0.48 mg for the premenopausal group, if 250mg iron stores are assumed. Seventythree percent of the premenopausal women and 30% of the postmenopausal subjects had calculated available iron intakes, assuming 500mg iron stores, which did not meet the recommended estimated requirements for absorbed iron. Assuming 250mg iron stores for the premenopausal women, 41% failed to meet this estimate.     

Serum transferrin receptor for the detection of iron deficiency in pregnancy

Measurements of circulating transferrin receptor provide a sensitive quantitative index of tissue iron deficiency in otherwise healthy subjects. This investigation was undertaken to examine the diagnostic utility of this new iron index in pregnancy. A battery of iron-related measurements, including serum transferrin receptor concentrations, was performed on 176 women in third-trimester pregnancy who were attending a university prenatal clinic. The mean receptor concentration of 5.96 +/- 2.37 mg/L (+/- 1 SD) did not differ significantly from concentrations in nonpregnant individuals and the frequency distributions were likewise comparable. Elevations in serum receptor greater than 8.5 mg/L occurred only in women with depleted iron stores defined by serum ferritin concentrations. Abnormal concentrations were found in 11 of 13 women with overt iron-deficiency anemia. Our findings indicate that serum receptor concentrations are not influenced by pregnancy per se and are a sensitive index of iron deficiency. By combining serum receptor and serum ferritin measurements, the entire spectrum of iron status in pregnancy can be assessed.     

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.     

Effect of daily or weekly multiple-micronutrient and iron foodlike tablets on body iron stores of Indonesian infants aged 6-12 mo: a double-blind, randomized, placebo-controlled trial

BACKGROUND: There is still uncertainty about the best procedure to alleviate iron deficiency. Additionally more reliable methods are needed to assess the effect of iron intervention. OBJECTIVE: We examined the efficacy of daily iron (10 mg), daily and weekly multiple-micronutrient supplementation (10 and 20 mg Fe, respectively) in improving body iron stores of Indonesian infants. DESIGN: Infants aged 6-12 mo were randomly allocated to 1 of 4 groups: daily multiple-micronutrients (DMM) foodlike tablets (foodLETs), weekly multiple-micronutrient (WMM) foodLETs, daily iron (DI) foodLETs, or daily placebo. Hemoglobin, ferritin, transferrin receptors, and C-reactive protein data were obtained at baseline and 23 wk. RESULTS: Body iron estimated from the ratio of transferrin receptors to ferritin was analyzed for 244 infants. At baseline, mean iron stores (0.5 +/- 4.1 mg/kg) did not differ among the groups, and 45.5% infants had deficits in tissue iron (body iron < 0). At week 23, the group DI had the highest increment in mean body iron (4.0 mg/kg), followed by the DMM group (2.3 mg/kg; P < 0.001 for both). The iron stores in the WMM group did not change, whereas the mean body iron declined in the daily placebo group (-2.2 mg/kg; P < 0.001). Compared with the daily placebo group, the DMM group gained 4.55 mg Fe/kg, the DI group gained 6.23 mg Fe/kg (both P < 0.001), and the WMM group gained 2.54 mg Fe/kg (P = 0.001). CONCLUSIONS: When compliance can be ensured, DI and DMM foodLETs are efficacious in improving and WMM is efficacious in maintaining iron stores among Indonesian infants.     

Iron status in 6-y-old children: associations with growth and earlier iron status

OBJECTIVE: To investigate the iron status of 6-y-old children and its association with growth and earlier iron status. DESIGN: In a cross-sectional study, children's body size measurements were recorded and blood samples taken near their sixth birthday. SUBJECTS: A sample of 188 children, randomly selected in two previous studies, was contacted, and 139(74%) agreed to participate. RESULTS: No children had iron deficiency anaemia, one was iron-deficient (serum ferritin (SF) <15 microg/l and mean corpuscular volume (MCV) <76 fl but 16% had depleted iron stores (SF<15 microg/l). Iron status indices were generally higher than at 1 and 2 y, but correlation was seen between iron status indices at 6 y and earlier values. Haemoglobin concentration at 6 y was negatively associated with length gain from birth to 1 y (B+/-s.e.=-1.269+/-0.452; P=0.007; adj. R2=0.119) (n=52), and proportional weight gain from birth to 1 y was higher among children with SF<15 microg/l at 6 y (295+/-33%; n=10) than those with SF> or =15 microg/l (258+/-31%; n=49) (P=0.001). MCV at 2 y predicted weight gain from 2 to 6 y (B+/-s.e.=1.721+/-0.581; P=0.005; adj. R2=0.153) (n=44); also, children with SF<15 microg/l at 6 y (n=9) gained 7.8+/-1.2 kg from 2 to 6 y, while children with SF> or =15 microg/l (n=35) gained 9.6+/-2.8 kg (P=0.007), furthermore a difference was seen in proportional weight gain from 2 to 6 y between children with depleted iron stores at 2 y and not, or 156+/-13 vs 169+/-18% (P=0.038). CONCLUSION: The results suggest that low iron status at 1 and 2 y might lead to slower growth up to 6 y of age. Low iron status at 1 and 2 y and/or slower growth from 1 and 2 y up to 6 y might contribute to worse iron status at 6 y, while faster growth in early childhood is related to lower iron status.     

Dietary iron positively influences bone mineral density in postmenopausal women on hormone replacement therapy

The associations of dietary intakes of iron and calcium on change in bone mineral density (BMD) were examined over 1 y in healthy nonsmoking postmenopausal women (mean age 55.6 +/- 4.6 y) stratified by hormone replacement therapy (HRT) use (HRT, n = 116; no HRT, n = 112). BMD was measured at lumbar spine L(2)-L(4), trochanter, femur neck, Ward's triangle, and total body using dual-energy X-ray absorptiometry at baseline and 1 y. Mean nutrient intakes were assessed using 8-d diet records. All women received 800 mg/d of supplemental elemental calcium. Regression analyses examined the effects of iron and calcium intakes on BMD change adjusting for years past menopause, baseline BMD, weight change, exercise, and energy intake. The interaction of iron with calcium on BMD change was assessed using tertiles of iron and calcium intake and estimated marginal mean change in BMD. Iron was associated (P < or = 0.05) with greater positive BMD change at the trochanter and Ward's triangle in women using HRT. Calcium was associated (P < or = 0.05) with BMD change at the trochanter and femur neck for women not using HRT. In women using HRT in the lowest tertile of calcium intake, change in femur neck BMD increased linearly as iron intake increased. In women not using HRT, BMD increased in the women in the highest tertile of calcium intake. We conclude that HRT use appears to influence the associations of iron and calcium on change in BMD.     

Risk of iron overload among middle-aged women

Iron overload, expressed as increased body iron stores, has been recognized as a potential hazard because it promotes the generation of oxygen radicals. We analyzed factors associated with serum ferritin levels (an indicator of body iron stores) among middle-aged women with a high prevalence of nutrient supplement use. Serum ferritin concentrations were determined on automated immunoassay for 487 healthy women with the mean age of 57 years who participated in the New York University Women's Health Study. The mean serum ferritin concentration in postmenopausal women was more than twice that in premenopausal women. Serum ferritin concentrations progressively increased with advancing age, but adjustment for menopausal status considerably weakened this association. Among non-dietary factors, nonwhite ethnicity, obesity and cigarette smoking were positively associated with serum ferritin concentrations. After adjustment for these factors and for menopausal status, serum ferritin levels were positively associated with meat intake and multivitamin use and inversely associated with breakfast cereal consumption. However, none of these lifestyle factors positively associated with serum ferritin levels had a significant impact on serum ferritin levels above 100 ng/ml (approximately equal to median concentration). Our results suggest that iron overload seems unlikely among middle aged women through their diet and nutritional supplements.     

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.     

Salt dual-fortified with iodine and micronized ground ferric pyrophosphate affects iron status but not hemoglobin in children in Cote d'Ivoire

Deficiencies of iron and iodine are common in West Africa, and salt is one of very few food vehicles available for fortification. Salt dual-fortified with iodine and micronized ground ferric pyrophosphate (FePP) was tested for its efficacy in rural, tropical C?te d'Ivoire. First, salt and iron intakes, and iron bioavailability were estimated using 3-d weighed food records in 24 households. Local iodized salt was then fortified with 3 mg Fe/g salt as ground FePP (mean particle size = 2.5 mum), and stability, sensory and acceptability trials were done. The dual fortified salt (DFS) was distributed to households and its efficacy compared with that of iodized salt (IS) in a 6-mo, double-blind trial in 5- to 15-y-old iron-deficient children (n = 123). All children were dewormed at baseline. After 6 mo, serum ferritin (SF) and transferrin receptor (TfR) concentrations as well as body iron stores improved significantly in the DFS group but not in the IS GROUP (P < 0.05). Body iron increased from 4.6 +/- 2.7 to 5.9 +/- 2.7 mg/kg (mean +/- SD) in the DFS group; concentrations before and after treatment in the IS group were 5.5 +/- 2.9 and 5.6 +/- 3.1 mg/kg, respectively. The hemoglobin concentration and the prevalence of anemia did not change in either group. The prevalences of malaria, soil-transmitted helminths, and riboflavin deficiency were 55, 14, and 66%, respectively. In tropical West Africa, low-grade salt fortified with micronized ground FePP increased body iron stores but not hemoglobin in children. Iron utilization may have been impaired by the high prevalence of malaria and concurrent nutrient deficiencies.     

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.     

Non-anemic iron depletion,oral iron supplementation and indices of copper status in college-aged females

OBJECTIVES: Indices of copper status, specifically serum copper and ceruloplasmin concentrations and erythrocyte superoxide dismutase activity, and iron status, including serum ferritin, transferrin receptors, hemoglobin and hematocrit, were studied in 27 college-aged females with adequate iron versus low iron stores. METHODS: Serum copper and ceruloplasmin concentrations, erythrocyte superoxide dismutase activity, serum ferritin, transferrin receptors, hemoglobin and hematocrit were studied in 15 females with non-anemic iron depletion before and after five weeks of iron supplementation and in 12 healthy iron-adequate females aged 19 to 28 years. RESULTS: Mean hemoglobin, hematocrit and ferritin concentrations of the control group (144 +/- 11 g/L, 43 +/- 3% and 38 +/- 15 micro g/L, respectively) were significantly higher than those of the iron depleted group prior to supplementation (134 +/- 9 g/L, 39 +/- 2% and 11 +/- 6 micro g/L, respectively). The serum transferrin receptor to serum ferritin ratio was significantly greater for the iron depleted group prior to supplementation (890 +/- 753) versus the control group (151 +/- 61). Mean serum copper and ceruloplasmin concentrations and erythrocyte superoxide dismutase activity of the iron-adequate control group (20.0 +/- 5.7 micro mol/L, 463 +/- 142 mg/L and 527 +/- 124 U/mL, respectively) were significantly higher than those of the iron depleted group (12.4 +/- 3.8 micro mol/L, 350 +/- 108 mg/L and 353 +/- 186 U/mL, respectively) prior to supplementation. Following iron supplementation, hematocrit and ferritin concentrations of the iron depleted group significantly increased to 42 +/- 3% and 26 +/- 8 micro g/L, respectively. Mean serum transferrin receptor concentrations and the serum transferrin receptor to ferritin ratios significantly decreased in the iron depleted group following supplementation (6.1 +/- 1.6 mg/L to 4.6 +/- 1.5 mg/L and 890 +/- 753 to 198 +/- 114, respectively). Iron supplementation also significantly increased the mean serum copper concentration to 14.2 +/- 5.4 micro mol/L and, in subjects with serum ferritin concentrations 相似文献   

Body iron stores and their determinants in healthy postmenopausal US women

BACKGROUND: Data on the determinants of body iron stores in middle-aged women are sparse. OBJECTIVE: We prospectively evaluated nondietary and dietary determinants of iron stores. DESIGN: Using blood samples collected in 1989-1990, we measured plasma ferritin concentrations in 620 healthy postmenopausal women aged 44-69 y who participated in the Nurses' Health Study. Food-frequency questionnaires completed in 1980, 1984, and 1986 were used to calculate average dietary intakes. Generalized linear regression and multiple logistic regression models were used to assess the association between plasma ferritin and its determinants. RESULTS: Among these postmenopausal women, the median plasma ferritin concentration was 73.8 ng/mL (interquartile range: 41.6-125.8 ng/mL), 2.7% were iron depleted (ferritin concentration < 12 ng/mL), and 9.8% had an elevated ferritin concentration (> 200 ng/mL). Age, time since menopause, time since the last postmenopausal hormone (PMH) use, body mass index, iron supplement use, and alcohol and heme-iron intakes were positively associated with ferritin concentrations, whereas PMH use, physical activity, aspirin use, and gastrointestinal ulcer were inversely related. The association between heme-iron intake and ferritin was most apparent among the women who consumed > 30 g alcohol/d. CONCLUSIONS: Our prospective data confirm that in postmenopausal women, intakes of heme iron, supplemental iron, and alcohol are dietary determinants of plasma ferritin, and age, PMH use, body mass index, physical activity, aspirin use, and gastrointestinal ulcer are nondietary determinants.     

Dietary intake and iron status of Australian vegetarian women.

BACKGROUND: Despite the possible overall health benefits of a vegetarian diet, there is concern that some vegetarians and infrequent meat eaters, particularly females, may have inadequate iron status because of low or no heme-iron intakes. OBJECTIVE: The objective was to investigate the nutritional intake and iron status of vegetarian women. DESIGN: The nutritional intakes of 50 free-living vegetarian women aged 18-45 y and 24 age-matched omnivorous control women were assessed by using 12-d weighed dietary records. Iron status was assessed by measuring hemoglobin and serum ferritin concentrations. RESULTS: There was no significant difference between mean (+/-SD) daily iron intakes of vegetarians and omnivores (10.7 +/- 4.4 and 9.9 +/- 2.9 mg, respectively), although heme-iron intakes were low in the vegetarians. Vegetarians had significantly lower intakes of protein (P < 0.01), saturated fat (P < 0.01), and cholesterol (P < 0.001), and significantly higher intakes of dietary fiber (P < 0.001) and vitamin C (P < 0.05). Mean serum ferritin concentrations were significantly lower (P = 0.025) in vegetarians (25.0 +/- 16.2 microg/L) than in omnivores (45.5 +/- 42.5 microg/L). However, similar numbers of vegetarians (18%) and omnivores (13%) had serum ferritin concentrations <12 microg/L, which is a value often used as an indicator of low iron stores. Hemoglobin concentrations were not significantly different. CONCLUSION: It is important that both vegetarian and omnivorous women maintain an adequate iron status and follow dietary practices that enhance iron absorption.