Iron metabolism in infants and children

Factors associated with syndemic anemia and stunting among children in Myanmar: A cross-sectional study from a positive deviance approach

BACKGROUND

Anemia and stunting in children are detrimental to the prospects of a normal, healthy upbringing. Having similar risk factors and serious consequences, the syndemic aspect of these two ailments is mostly underrated, and positive deviant (PD) factors that ensure non-anemic status in stunted children have not been studied to date.

METHODS

This study aimed to identify PD factors that have potential to prevent syndemic anemia among stunted children aged 6-59 months in Myanmar. This was a cross-sectional secondary analysis of the Myanmar Demographic and Health Survey (DHS) data conducted in 2016, applying the PD concept, where children who were stunted without anemia were considered as PDs.

RESULTS

Among 1248 stunted children, those who had the syndemic condition were compared with their PD peers in terms of maternal characteristics as well as socioeconomic and health-related factors. Multivariable logistic regression analyses were used to identify the determinants of syndemic state. The results showed that three out of every five stunted children were anemic. The syndemic risk was decreased among children of maternal age groups 20-34 years and 35-44 years: [aOR] = 0.19, 95% CI = 0.05-0.69; p = 0.012, and aOR = 0.19, 95% CI = 0.05-0.75; p = 0.018, respectively. Moderately stunted children (aOR = 0.53, 95% CI = 0.34-0.81; p = 0.004) and children who were not currently breastfed (aOR = 1.56, 95% CI = 1.01-2.41; p = 0.044) were less likely to develop the syndemic condition.

CONCLUSION

Maternal age, stunting severity, breastfeeding duration, and maternal anemic status are strong predictors in determining hemoglobin concentrations among stunted children. This study suggests that nutritional interventions targeting PD factors could represent syndemic action in improving child health.

Regulation of iron absorption in infants

BACKGROUND

Iron programs in low- and middle-income countries often target infants and young children. Limited data from human infants and mouse models suggest that homeostatic control of iron absorption is incomplete in early infancy. Excess iron absorption during infancy may have detrimental effects.

OBJECTIVES

Our aims were to 1) investigate determinants of iron absorption in infants aged 3-15 mo and assess whether regulation of iron absorption is fully mature during this period and 2) define the threshold ferritin and hepcidin concentrations in infancy that trigger upregulation of iron absorption.

METHODS

We performed a pooled analysis of standardized, stable iron isotope absorption studies performed by our laboratory in infants and toddlers. We used generalized additive mixed modeling (GAMM) to examine relationships between ferritin, hepcidin, and fractional iron absorption (FIA).

RESULTS

Kenyan and Thai infants aged 2.9-15.1 mo (n = 269) were included; 66.8% were iron deficient and 50.4% were anemic. In regression models, hepcidin, ferritin, and serum transferrin receptor were significant predictors of FIA, whereas C-reactive protein was not. In the model including hepcidin, hepcidin was the strongest predictor of FIA (β = -0.435). In all models, interaction terms, including age, were not significant predictors of FIA or hepcidin. The fitted GAMM trend of ferritin versus FIA showed a significant negative slope until ferritin of 46.3 μg/L (95% CI: 42.1, 50.5 μg/L), which corresponded to an FIA decrease from 26.5% to 8.3%; above this ferritin value, FIA remained stable. The fitted GAMM trend of hepcidin versus FIA showed a significant negative slope until hepcidin of 3.15 nmol/L (95% CI: 2.67, 3.63 nmol/L), above which FIA remained stable.

CONCLUSIONS

Our findings suggest that the regulatory pathways of iron absorption are intact in infancy. In infants, iron absorption begins to increase at threshold ferritin and hepcidin values of ∼46 μg/L and ∼3 nmol/L, respectively, similar to adult values.

Fecal Iron Measurement in Studies of the Human Intestinal Microbiome

Iron is an essential micronutrient for humans and their intestinal microbiota. Host intestinal cells and iron-dependent bacteria compete for intraluminal iron, so the composition and functions of the gut microbiota may influence iron availability. Studies of the effects of the microbiota or probiotic interventions on host iron absorption may be particularly relevant to settings with high burdens of iron deficiency and gastrointestinal infections, since inflammation reduces iron bioavailability and unabsorbed intraluminal iron may modify the composition of the microbiota. The quantification of stool iron content may serve as an indicator of the amount of intraluminal iron to which the intestinal microbiota is exposed, which is particularly relevant for studies of the effect of iron on the intestinal microbiome, where fecal samples collected for purposes of microbiome characterization can be leveraged for stool iron analysis. However, few studies are available to guide researchers in the selection and implementation of stool iron assays, particularly because cross-comparison of available methods is limited in literature. This review aims to describe the available stool iron quantification methods and highlight their potential application in studies of iron-microbiome relationships, with a focus on pediatric research. MS-based methods offer high sensitivity and precision, but the need for expensive equipment and the high per-sample and maintenance costs may limit their widespread use. Conversely, colorimetric assays offer lower cost, ease of use, and rapid turnaround times but have thus far been optimized primarily for blood-derived matrices rather than stool. Further research efforts are needed to validate and standardize methods for stool iron assessment and to determine if the incorporation of such analyses in human microbiome studies 1) yields insights into the interactions between intestinal microbiota and iron and 2) contributes to the development of interventions that mitigate iron deficiency and promote a healthy microbiome.

Iron Bioavailability from Infant Cereals Containing Whole Grains and Pulses: A Stable Isotope Study in Malawian Children

BACKGROUND

Compared with infant cereals based on refined grains, an infant cereal containing whole grains (WGs) and pulses with adequate amounts of ascorbic acid to protect against absorption inhibitors could be a healthier source of well-absorbed iron. However, iron absorption from such cereals is uncertain.

OBJECTIVE

We measured iron bioavailability from ferrous fumarate (Fefum) added to commercial infant cereals containing 1) refined wheat flour (reference meal), 2) WG wheat and lentil flour (WG-wheat-lentil), 3) WG wheat and chickpea flour (WG-wheat-chickpeas), and 4) WG oat flour (WG-oat) and from ferrous bisglycinate (FeBG) added to the same oat-based cereal (WG-oat-FeBG).

METHODS

In a prospective, single-blinded randomized crossover study, 6- to 14-mo-old Malawian children (n = 30) consumed 25-g servings of all 5 test meals containing 2.25 mg stable isotope-labeled iron and 13.5 mg ascorbic acid. Fractional iron absorption (FIA) was assessed by erythrocyte incorporation of isotopes after 14 d. Comparisons were made using linear mixed models.

RESULTS

Seventy percent of the children were anemic and 67% were iron deficient. Geometric mean FIA percentages (-SD, +SD) from the cereals were as follows: 1) refined wheat, 12.1 (4.8, 30.6); 2) WG-wheat-lentil, 15.8 (6.6, 37.6); 3) WG-wheat-chickpeas, 12.8 (5.5, 29.8); and 4) WG-oat, 9.2 (3.9, 21.5) and 7.4 (2.9, 18.9) from WG-oat-FeBG. Meal predicted FIA (P ≤ 0.001), whereas in pairwise comparisons, only WG-oat-FeBG was significantly different compared with the refined wheat meal (P = 0.02). In addition, FIAs from WG-wheat-lentil and WG-wheat-chickpeas were significantly higher than from WG-oat (P = 0.002 and P = 0.04, respectively) and WG-oat-FeBG (P < 0.001 and P = 0.004, respectively).

CONCLUSION

In Malawian children, when given with ascorbic acid at a molar ratio of 2:1, iron bioavailability from Fefum-fortified infant cereals containing WG wheat and pulses is ≈13-15%, whereas that from FeBG- and Fefum-fortified infant cereals based on WG oats is ≈7-9%.

The effect of iron dosing schedules on plasma hepcidin and iron absorption in Kenyan infants

BACKGROUND

In adults, oral iron doses increase plasma hepcidin (PHep) for 24 h, but not for 48 h, and there is a circadian increase in PHep over the day. Because high PHep decreases fractional iron absorption (FIA), alternate day iron dosing in the morning may be preferable to consecutive day dosing. Whether these effects occur in infants is uncertain.

OBJECTIVE

Using stable iron isotopes in Kenyan infants, we compared FIA from morning and afternoon doses and from consecutive, alternate (every second day) and every third day iron doses.

METHODS

In prospective studies, we measured and compared FIA and the PHep response from 1) meals fortified with a 12-mg iron micronutrient powder given in the morning or afternoon (n = 22); 2) the same given on consecutive or alternate days (n = 21); and 3) a 12-mg iron supplement given on alternate days or every third day (n = 24).

RESULTS

In total, 65.7% of infants were anemic. In study 1, PHep did not differ between morning and afternoon (P = 0.072), and geometric mean FIA[-SD, +SD](%) did not differ between the morning and afternoon doses [15.9 (8.9, 28.6) and 16.1 (8.7, 29.8), P = 0.877]. In study 2, PHep was increased 24 h after oral iron (P = 0.014), and mean FIA [±SD](%) from the baseline dose [23.3 (10.9)] was greater than that from the consecutive day dose (at 24 h) [20.1 (10.4); P = 0.042] but did not differ from the alternate day dose (at 48 h) [20.9 (13.4); P = 0.145]. In study 3, PHep was not increased 48 and 72 h after oral iron (P = 0.384), and the geometric mean FIA[-SD, +SD](%) from doses given at baseline, alternate days, and every third day did not differ [12.7 (7.3, 21.9), 13.8 (7.8, 24.2), and 14.8 (8.8, 24.8), respectively; P = 0.080].

CONCLUSIONS

In Kenyan infants given 12 mg oral iron, morning and afternoon doses are comparably absorbed, dosing on consecutive days increases PHep and modestly decreases iron absorption compared with alternate day dosing, and dosing on alternate days or every third day does not increase PHep or decrease absorption. This trial was registered at clinicaltrials.gov as NCT02989311 and NCT03617575.

Iron Homeostasis Disruption and Oxidative Stress in Preterm Newborns

Iron is an essential micronutrient for early development, being involved in several cellular processes and playing a significant role in neurodevelopment. Prematurity may impact on iron homeostasis in different ways. On the one hand, more than half of preterm infants develop iron deficiency (ID)/ID anemia (IDA), due to the shorter duration of pregnancy, early postnatal growth, insufficient erythropoiesis, and phlebotomy losses. On the other hand, the sickest patients are exposed to erythrocytes transfusions, increasing the risk of iron overload under conditions of impaired antioxidant capacity. Prevention of iron shortage through placental transfusion, blood-sparing practices for laboratory assessments, and iron supplementation is the first frontier in the management of anemia in preterm infants. The American Academy of Pediatrics recommends the administration of 2 mg/kg/day of oral elemental iron to human milk-fed preterm infants from one month of age to prevent ID. To date, there is no consensus on the type of iron preparations, dosages, or starting time of administration to meet optimal cost-efficacy and safety measures. We will identify the main determinants of iron homeostasis in premature infants, elaborate on iron-mediated redox unbalance, and highlight areas for further research to tailor the management of iron metabolism.

Type I interferon underlies severe disease associated with Junín virus infection in mice

Junín virus (JUNV) is one of five New World mammarenaviruses (NWMs) that causes fatal hemorrhagic disease in humans and is the etiological agent of Argentine hemorrhagic fever (AHF). The pathogenesis underlying AHF is poorly understood; however, a prolonged, elevated interferon-α (IFN-α) response is associated with a negative disease outcome. A feature of all NWMs that cause viral hemorrhagic fever is the use of human transferrin receptor 1 (hTfR1) for cellular entry. Here, we show that mice expressing hTfR1 develop a lethal disease course marked by an increase in serum IFN-α concentration when challenged with JUNV. Further, we provide evidence that the type I IFN response is central to the development of severe JUNV disease in hTfR1 mice. Our findings identify hTfR1-mediated entry and the type I IFN response as key factors in the pathogenesis of JUNV infection in mice.

An Overview of Iron in Term Breast-Fed Infants

BACKGROUND

Iron is an essential nutrient for normal growth and neurodevelopment of infants. Iron deficiency (ID) remains the most common micronutrient deficiency worldwide. There are convincing data that ID is associated with negative effects on neurological and psychomotor development.

OBJECTIVES

In this review, we provide an overview of current knowledge of the importance of iron in normal term breast-fed infants with a focus on recommendations, metabolism, and iron requirements.

CONCLUSIONS

Health organizations around the world recommend the introduction of iron-rich foods or iron supplements for growing infants to prevent ID. However, there is no routine screening for ID in infancy. Multicenter trials with long-term follow-up are needed to investigate the association between iron fortification/supplementation and various health outcomes.

Implications of inconsistent anaemia policies for children and adolescents in Africa

OBJECTIVE

To evaluate the quality of policies concerning the diagnosis, treatment and prevention of anaemia in children and adolescents; to determine to what extent these are evidence-based; and to use this analysis to inform the policy-making process.

SUBJECTS

Children and adolescents in sub-Saharan Africa.

SETTING

Almost 50 % of children and adolescents in sub-Saharan Africa are anaemic, which has profound effects on their intellectual and physical development and their chance of survival. Evidence-based policies are essential to reduce anaemia but because it is caused by an array of interdependent factors, developing policies is challenging.

DESIGN

Forty-six policy documents concerning the diagnosis, treatment and prevention of anaemia in children and adolescents were identified and analysed.

RESULTS

There was policy consensus on the usefulness of Fe supplements, the need to treat co-morbidities and the use of blood transfusions for severe anaemia. Information about diagnosis was scarce, and messages regarding the control of anaemia were mixed. Few of the policies were tailored for the African context and they were located on several websites hosted by different health programmes.

CONCLUSIONS

The weakest aspects of the policies and consequently the priorities for better policy making were: lack of adherence to WHO recommendations for guideline development; little involvement of African practitioners/policy makers in the guideline group and as peer reviewers; and lack of harmonisation, demonstrating the need to establish a single body responsible for developing/revising anaemia policies.

Identification, prevention and treatment of iron deficiency during the first 1000 days

Iron deficiency is a global problem across the life course, but infants and their mothers are especially vulnerable to both the development and the consequences of iron deficiency. Maternal iron deficiency during pregnancy can predispose offspring to the development of iron deficiency during infancy, with potentially lifelong sequelae. This review explores iron status throughout these "first 1000 days" from pregnancy through two years of age, covering the role of iron and the epidemiology of iron deficiency, as well as its consequences, identification, interventions and remaining research gaps.

Effect of supplementation with ferrous sulfate or iron bis-glycinate chelate on ferritin concentration in Mexican schoolchildren: a randomized controlled trial

Background

Iron deficiency is one of the most common nutritional deficiencies worldwide. It is more prevalent when iron requirements are increased during pregnancy and during growth spurts of infancy and adolescence. The last stage in the process of iron depletion is characterized by a decrease in hemoglobin concentration, resulting in iron deficiency anemia. Iron deficiency, even before it is clinically identified as anemia, compromises the immune response, physical capacity for work, and intellectual functions such as attention level. Therefore, interventions addressing iron deficiency should be based on prevention rather than on treatment of anemia. The aim of this study was to compare short- and medium-term effects on ferritin concentration of daily supplementation with ferrous sulfate or iron bis-glycinate chelate in schoolchildren with iron deficiency but without anemia.

Methods

Two hundred schoolchildren from public boarding schools in Mexico City who had low iron stores as assessed by serum ferritin concentration but without anemia were randomly assigned to a daily supplement of 30 mg/day of elemental iron as ferrous sulfate or iron bis-glycinate chelate for 12 weeks. Iron status was evaluated at baseline, one week post-supplementation (short term), and 6 months (medium term) after supplementation.

Results

Ferritin concentration increased significantly between baseline and post-supplementation as well as between baseline and 6 months after supplementation. One week post-supplementation no difference was found in ferritin concentration between iron compounds, but 6 months after supplementation ferritin concentration was higher in the group that received bis-glycinate chelate iron. However, there is no difference in the odds for low iron storage between 6 months after supplementation versus the odds after supplementation; nor were these odds different by type of supplement. Hemoglobin concentration did not change significantly in either group after supplementation.

Conclusions

Supplementing with 30 mg/d of elementary iron, either as ferrous sulfate or iron bis-glycinate chelate for 90 days, showed positive effects on increasing ferritin concentration in schoolchildren with low iron stores, and this effect persisted 6 months after supplementation.

Present and past Helicobacter pylori infection in Mexican school children

BACKGROUND

In developing countries, more than 50% of children have serological evidence of Helicobacter pylori infection. However, serological tests for H. pylori did not differentiate between active and past infection. The objectives of this study were to estimate the frequency of active and past H. pylori infection utilizing functional urea breath test (UBT) and serological tests and evaluate factors associated with the infection.

METHODS

A total of 675 school children, 6-13 years of age, participated. UBT was performed to detect active H. pylori infection. Blood samples were obtained to determine iron status and Immunoglobulin G (IgG) responses to the H. pylori whole-cell and to Cag A antigens by antigen-specific enzyme-linked immunosorbent assays. Weight, height, and sociodemographic characteristics were recorded.

RESULTS

A total of 37.9% (95% Confidence Intervals (CI): 34.2-41.6) of school children had active or past H. pylori infection; of them, 73.8% (CI95% 68.4-79.2) were carrying CagA-positive strain, 26.5% (CI95% 23.2-29.8) had active infection, and 11.4% (95%CI: 9.0-13.8) had evidence of past H. pylori infection. School children with iron deficiency and low height for age had higher risk of H. pylori infection: [OR to active or past infection was 2.30 (CI 95% 1.01-5.23) and to active infection it was 2.64 (CI 95% 1.09-6.44)] compared to school children with normal iron status and height for age or with normal iron status but low height for age or with iron deficiency and normal height for age.

CONCLUSIONS

The estimated prevalence of infection depends of the test utilized. Frequency of H. pylori infection and carrying CagA-positive strains was high in this population. Malnutrition was associated with active H. pylori infection.

Iron status and systemic inflammation, but not gut inflammation, strongly predict gender-specific concentrations of serum hepcidin in infants in rural Kenya

Hepcidin regulation by competing stimuli such as infection and iron deficiency has not been studied in infants and it’s yet unknown whether hepcidin regulatory pathways are fully functional in infants. In this cross-sectional study including 339 Kenyan infants aged 6.0±1.1 months (mean±SD), we assessed serum hepcidin-25, biomarkers of iron status and inflammation, and fecal calprotectin. Prevalence of inflammation, anemia, and iron deficiency was 31%, 71%, 26%, respectively. Geometric mean (±SD) serum hepcidin was 6.0 (±3.4) ng/mL, and was significantly lower in males than females. Inflammation (C-reactive protein and interleukin-6) and iron status (serum ferritin, zinc protoporphyrin and soluble transferrin receptor) were significant predictors of serum hepcidin, explaining nearly 60% of its variance. There were small, but significant differences in serum hepcidin comparing iron deficient anemic (IDA) infants without inflammation to iron-deficient anemic infants with inflammation (1.2 (±4.9) vs. 3.4 (±4.9) ng/mL; P<0.001). Fecal calprotectin correlated with blood/mucus in the stool but not with hepcidin. Similarly, the gut-linked cytokines IL-12 and IL-17 did not correlate with hepcidin. We conclude that hepcidin regulatory pathways are already functional in infancy, but serum hepcidin alone may not clearly discriminate between iron-deficient anemic infants with and without infection. We propose gender-specific reference values for serum hepcidin in iron-replete infants without inflammation.

Inhibition of hepcidin transcription by growth factors

The hepatic peptide hormone hepcidin controls the duodenal absorption of iron, its storage, and its systemic distribution. Hepcidin production is often insufficient in chronic hepatitis C and alcoholic liver disease, leading to hyperabsorption of iron and its accumulation in the liver. Hepatocyte growth factor (HGF) and epidermal growth factor (EGF) mediate hepatic regeneration after liver injury. We examined the effect of these growth factors on hepcidin synthesis by hepatocytes. HGF and EGF treatment of primary mouse hepatocytes, as well as EGF administration in mice, suppressed hepcidin messenger RNA (mRNA) synthesis. The suppression of hepcidin by these growth factors was transcriptional, and was mediated by a direct effect of HGF and EGF on the bone morphogenetic protein (BMP) pathway regulating hepcidin synthesis. We further show that growth factors interfered with nuclear localization of activated sons of mothers against decapentaplegic (Smad) and increased the nuclear pool of the BMP transcriptional corepressor TG-interacting factor (TGIF). In a kinase screen with small-molecule kinase inhibitors, inhibitors in the PI3 kinase pathway and in the mitogen-activated ERK kinase/extracellular signal-regulated kinase (MEK/ERK) pathway prevented HGF suppression of hepcidin in primary mouse hepatocytes.

CONCLUSION

HGF and EGF suppress hepatic hepcidin synthesis, in part through PI3 kinase MEK/ERK kinase pathways which may be modulating the nuclear localization of BMP pathway transcriptional regulators including activated Smads1/5/8 and the corepressor TGIF. EGF, HGF, and possibly other growth factors that activate similar pathways may contribute to hepcidin suppression in chronic liver diseases, promote iron accumulation in the liver, and exacerbate the destructive disease processes.

Effect on haematological and anthropometric parameters of iron supplementation in the first 2 years of life. Risks and benefits

Effects of iron supplementation (IS) on haematological and anthropometric parameters in a cohort of 121 healthy children, followed from 6 to 24 months of life, in the Paediatric Department, Second University of Naples, were evaluated. Children were randomly segregated in four groups: (1) exclusively breast feeding (BF) weaned with non-iron fortified (NIF) foods, (2) BF and iron fortified formulas (IFF) and foods, (3) exclusively IFF and foods, (4) BF and oral iron supplementation (OIS). Haematological parameters (Hb, MCV, Serum ferritin and transferrin saturation) in addition to anthropometric measurements (length and weight) were obtained. Results from the study at 6, 12, 18 and 24 months showed significantly lower values of haematological parameters in BF infants than other groups and in IFF infants than in those with OIS. In contrast children with OIS showed significant lower length. It appears that IS may be of limited or no benefit for growth in non-iron deficient children.

Effects of iron supplementation on serum hepcidin and serum erythropoietin in low-birth-weight infants

BACKGROUND

The iron-regulatory hormone hepcidin has not been studied in infants, who experience large physiologic changes in iron status.

OBJECTIVE

The objective was to study hepcidin and erythropoietin and their correlation with iron status in iron-replete and iron-deficient low-birth-weight (LBW) infants-a group at particular risk of iron deficiency (ID).

DESIGN

We randomly assigned 285 otherwise healthy LBW infants to receive, from 6 wk to 6 mo of age, 3 doses of iron supplements: 0 (placebo), 1, or 2 mg/kg daily. Hepcidin, erythropoietin, hemoglobin, and variables of iron status were analyzed.

RESULTS

Serum hepcidin did not change over time in the placebo group, despite a rapid decrease in serum ferritin. In iron-supplemented infants, hepcidin increased significantly, reaching a mean (±SD) concentration of 19.2 ± 2.5 ng/mL in the 2-mg/kg group compared with 13.0 ± 2.6 ng/mL in the placebo group at age 6 mo (P < 0.001). The difference was even larger between iron-deficient and iron-replete infants. Hepcidin was independently positively correlated with ferritin at all ages and was negatively correlated with the transferrin receptor concentration at age 6 wk and with transferrin at age 6 mo. Erythropoietin was initially similar between groups but decreased significantly in iron-supplemented infants. In addition to being negatively correlated with hemoglobin, it was also independently negatively correlated with indicators of iron status.

CONCLUSIONS

Hepcidin is closely associated with iron status and may be a useful indicator of iron stores and ID in infants. Erythropoietin is negatively correlated with iron status, which suggests a feedback mechanism that needs further study. This trial is registered at clinicaltrials.gov as NCT00558454.

A micronutrient powder with low doses of highly absorbable iron and zinc reduces iron and zinc deficiency and improves weight-for-age Z-scores in South African children

Micronutrient powders (MNP) are often added to complementary foods high in inhibitors of iron and zinc absorption. Most MNP therefore include high amounts of iron and zinc, but it is no longer recommended in malarial areas to use untargeted MNP that contain the Reference Nutrient Intake for iron in a single serving. The aim was to test the efficacy of a low-iron and -zinc (each 2.5 mg) MNP containing iron as NaFeEDTA, ascorbic acid (AA), and an exogenous phytase active at gut pH. In a double-blind controlled trial, South African school children with low iron status (n = 200) were randomized to receive either the MNP or the unfortified carrier added just before consumption to a high-phytate maize porridge 5 d/wk for 23 wk; primary outcomes were iron and zinc status and a secondary outcome was somatic growth. Compared with the control, the MNP increased serum ferritin (P < 0.05), body iron stores (P < 0.01) and weight-for-age Z-scores (P < 0.05) and decreased transferrin receptor (P < 0.05). The prevalence of iron deficiency fell by 30.6% (P < 0.01) and the prevalence of zinc deficiency decreased by 11.8% (P < 0.05). Absorption of iron from the MNP was estimated to be 7-8%. Inclusion of an exogenous phytase combined with NaFeEDTA and AA may allow a substantial reduction in the iron dose from existing MNP while still delivering adequate iron and zinc. In addition, the MNP is likely to enhance absorption of the high native iron content of complementary foods based on cereals and/or legumes.

Benefits and risks of iron supplementation in anemic neonatal pigs

Iron deficiency is a common health problem. The most severe consequence of this disorder is iron deficiency anemia (IDA), which is considered the most common nutritional deficiency worldwide. Newborn piglets are an ideal model to explore the multifaceted etiology of IDA in mammals, as IDA is the most prevalent deficiency disorder throughout the early postnatal period in this species and frequently develops into a critical illness. Here, we report the very low expression of duodenal iron transporters in pigs during the first days of life. We postulate that this low expression level is why the iron demands of the piglet body are not met by iron absorption during this period. Interestingly, we found that a low level of duodenal divalent metal transporter 1 and ferroportin, two iron transporters located on the apical and basolateral membrane of duodenal absorptive enterocytes, respectively, correlates with abnormally high expression of hepcidin, despite the poor hepatic and overall iron status of these animals. Parenteral iron supplementation by a unique intramuscular administration of large amounts of iron dextran is current practice for the treatment of IDA in piglets. However, the potential toxicity of such supplemental iron implies the necessity for caution when applying this treatment. Here we demonstrate that a modified strategy for iron supplementation of newborn piglets with iron dextran improves the piglets' hematological status, attenuates the induction of hepcidin expression, and minimizes the toxicity of the administered iron.

miR-584 mediates post-transcriptional expression of lactoferrin receptor in Caco-2 cells and in mouse small intestine during the perinatal period

MicroRNAs function as gene expression modulators that are critical for mammalian development. Lactoferrin receptor on the apical membrane of enterocytes has been suggested to play key roles in the absorption of lactoferrin-bound iron from breast milk. The objective of this study was to identify mechanisms of microRNA mediated post-transcriptional regulation of the lactoferrin receptor. Sequence analyses revealed that the miR-584 sequence is identical in human, mouse and rat, and there is a conserved region complementary to the seed region (5' nucleotides 2-8) of miR-584 within the lactoferrin receptor mRNA-3'-untranslated region. miR-584 was further found to co-localize with lactoferrin receptor mRNA in mouse small intestine. The 3'-untranslated region of human lactoferrin receptor mRNA was cloned into pGL3-control luciferase reporter vector. By luciferase reporter assays in HEK293 cells, miR-584 mimic specifically repressed the reporter activity in a dose-dependent manner. miR-584 mimic reduced endogenous lactoferrin receptor protein expression in Caco-2 cells, without significantly affecting the mRNA level. We also determined that miR-584 expression is inversely correlated with lactoferrin receptor mRNA and protein expression. Taken together, we propose that miR-584 contributes to the post-transcriptional expression of lactoferrin receptor during the perinatal period. These findings demonstrate a novel example of how microRNAs may be involved in regulation of nutrient metabolism in the newborn.

Iron therapy for preterm infants

Preterm infants are at risk for both iron deficiency and iron overload. The role of iron in multiple organ functions suggests that iron supplementation is essential for the preterm infant. Conversely, the potential for iron overload and the poorly developed antioxidant measures in the preterm infant argue against indiscriminate iron supplementation in this population. This article reviews the predisposing factors and consequences of iron deficiency and iron overload in the preterm infant, discusses the current recommendation for iron supplementation and its appropriateness, and describes potential management strategies that strike a balance between iron deficiency and iron toxicity.

Iron metabolism in children: confounding factors

Characterization of iron metabolism in infants and children may be confounded by the diverse effects of developmental, genetic, and acquired influences on iron metabolism and laboratory measurements of iron status, especially in areas with intense perennial transmission of Plasmodium falciparum malaria. In the Pemba iron and folic acid supplementation trial, the coadministration of folic acid with iron is a further confounding factor. Because the design of the Pemba iron and folic acid supplementation study did not include a group that received iron supplementation without folic acid, the observed increase in serious adverse events cannot be ascribed unequivocally to iron alone, to folic acid alone, or to the combination of the two. In interpreting the results from the Pemba iron and folic acid supplementation trial, additional analyses of existing data from the trial and from earlier studies in the area could help clarify the roles of iron and folic acid.