Relation of neonatal iron status to individual variability in neonatal temperament

Early life stress and iron metabolism in developmental psychoneuroimmunology

An estimated 250 million children face adverse health outcomes from early life exposure to severe or chronic social, economic, and nutritional adversity, highlighting/emphasizing the pressing concern about the link between ELS and long-term implications on mental and physical health. There is significant overlap between populations experiencing high levels of chronic stress and those experiencing iron deficiency, spotlighting the potential role of iron as a key mediator in this association. Iron, an essential micronutrient for brain development and immune function, is often depleted in stress conditions. Iron deficiency among the most common nutrient deficiencies in the world. Fetal and infant iron status may thus serve as a crucial intermediary between early chronic psychological stress and subsequent immune system changes to impact neurodevelopment. The review presents a hypothesized pathway between early life stress (ELS), iron deficiency, and neurodevelopment through the hypothalamic-pituitary-adrenocortical (HPA) axis and the IL-6-hepcidin axis. This hypothesis is derived from (1) evidence that stress impacts iron status (2) long-term neurodevelopmental outcomes that are shared by ELS and iron deficiency exposure, and (3) possible mechanisms for how iron may mediate the relation between ELS and iron deficiency through alterations in the developing immune system. The article concludes by proposing future research directions, emphasizing the need for rigorous studies to elucidate how stress and iron metabolism interact to modify the developing immune system. Understanding these mechanisms could open new avenues for improving human health and neurodevelopment for women and children globally, making it a timely and vital area of study in psychoneuroimmunology research.

Biomarkers of Brain Dysfunction in Perinatal Iron Deficiency

Iron deficiency in the fetal and neonatal period (perinatal iron deficiency) bodes poorly for neurodevelopment. Given its common occurrence and the negative impact on brain development, a screening and treatment strategy that is focused on optimizing brain development in perinatal iron deficiency is necessary. Pediatric societies currently recommend a universal iron supplementation strategy for full-term and preterm infants that does not consider individual variation in body iron status and thus could lead to undertreatment or overtreatment. Moreover, the focus is on hematological normalcy and not optimal brain development. Several serum iron indices and hematological parameters in the perinatal period are associated with a risk of abnormal neurodevelopment, suggesting their potential use as biomarkers for screening and monitoring treatment in infants at risk for perinatal iron deficiency. A biomarker-based screening and treatment strategy that is focused on optimizing brain development will likely improve outcomes in perinatal iron deficiency.

Maternal gestational iron status and infant haematological and neurodevelopmental outcomes

Prevention of iron deficiency (ID), the most common micronutrient deficiency in infants and children, begins prenatally by ensuring adequate fetal loading. Adequate intrauterine iron status is crucial for normal fetal brain development, postnatal brain performance and prevention of early postnatal iron deficiency, particularly in infants fed exclusively human milk. Adequate fetal loading may be achieved in some cases through adequate maternal iron levels prior to pregnancy and oral iron supplementation during pregnancy. However, because so many women are iron-deficient leading up to pregnancy, coupled with the negative iron balance induced by pregnancy, a large number of women remain iron-deficient during pregnancy. More consistent iron-specific early screening and more effective iron delivery approaches are needed to solve this global problem.

The Interaction between Psychological Stress and Iron Status on Early-Life Neurodevelopmental Outcomes

This review presents evidence from animal and human studies demonstrating the possible connection and significant impact of poor iron status and psychological distress on neurocognitive development during pregnancy and the neonatal period, with implications for long-term cognition. Stress and iron deficiency are independently prevalent and thus are frequently comorbid. While iron deficiency and early-life stress independently contribute to long-term neurodevelopmental alterations, their combined effects remain underexplored. Psychological stress responses may engage similar pathways as infectious stress, which alters fundamental iron metabolism processes and cause functional tissue-level iron deficiency. Psychological stress, analogous to but to a lesser degree than infectious stress, activates the hypothalamic-pituitary-adrenocortical (HPA) axis and increases proinflammatory cytokines. Chronic or severe stress is associated with dysregulated HPA axis functioning and a proinflammatory state. This dysregulation may disrupt iron absorption and utilization, likely mediated by the IL-6 activation of hepcidin, a molecule that impedes iron absorption and redistributes total body iron. This narrative review highlights suggestive studies investigating the relationship between psychological stress and iron status and outlines hypothesized mechanistic pathways connecting psychological stress exposure and iron metabolism. We examine findings regarding the overlapping impacts of early stress exposure to iron deficiency and children's neurocognitive development. We propose that studying the influence of psychological stress on iron metabolism is crucial for comprehending neurocognitive development in children exposed to prenatal and early postnatal stressors and for children at risk of early iron insufficiency. We recommend future directions for dual-exposure studies exploring iron as a potential mediating pathway between early stress and offspring neurodevelopment, offering opportunities for targeted interventions.

Iron status, development, and behavior in young children in the Pennsylvania foster care system

BACKGROUND

Children in foster care are classified as a highly vulnerable population and struggle with both physical and mental health problems. Medical conditions, like poor nutritional status, remain understudied in children in foster care. To our knowledge, few studies in children in U.S. foster care have quantified the prevalence of anemia, and no studies have examined the association between anemia status and relevant developmental and behavioral outcomes.

OBJECTIVE/AIMS

(1) To determine the prevalence of anemia among children in or adopted from Pennsylvania foster care, between the ages of six months to ten years and (2) To examine if a child's anemia status is associated with greater odds of relevant developmental and behavioral diagnoses.

METHODS

We conducted a secondary data analysis utilizing the Medicaid Analytic eXtract database between 2010-2015. Children six months-ten years were included in the analysis if they were in or had been adopted from Pennsylvania foster care. Logistic regression was used to calculate adjusted odds ratios (AOR) with 95% confidence intervals for the association between iron status and health outcomes.

RESULTS

A total of 50,311 children were included in our sample, of which 1,365 children (2.7%) were diagnosed with anemia. Children diagnosed with anemia had greater odds of delayed milestones (AOR: 2.38 [1.64-3.45]), specific delays in development (AOR: 1.59 [1.23-2.07]), adjustment disorder (AOR: 1.59 [1.06-2.39]), and irritability (AOR: 10.57 [3.36-33.25]), than children not diagnosed with anemia.

CONCLUSION

The prevalence of anemia among children between six months-ten years in or adopted from the Pennsylvania foster care system is within the national rate of U.S. childhood anemia. Odds of several relevant developmental and behavioral diagnoses were greater among children diagnosed with anemia than children who were not.

The importance of iron deficiency in pregnancy on fetal, neonatal, and infant neurodevelopmental outcomes

The role of iron in neurodevelopment has long been recognized, and the adverse effects of early-life iron deficiency on brain development and subsequent function across the lifespan continue to be a subject of research. A greater appreciation of the contribution of maternal preconceptional iron status and fetal iron accretion to offspring, postnatal iron status, and brain health across the lifespan has occurred over the past decade. This paradigm shift in thinking links two previously relatively siloed literatures: neonatal iron deficiency and postnatal iron deficiency. The understanding that iron accretion during the fetal period strongly influences postnatal iron balance has led to an appreciation of the importance and value of ensuring proper fetal iron loading. This article reviews the dynamics of fetal iron metabolism, the role of iron in the developing fetal brain, the short- and long-term neurobehavioral consequences of fetal iron underloading, and the potential mechanisms that account for the long-term effects of fetal/neonatal iron deficiency.

Early life nutrition and brain development: breakthroughs, challenges and new horizons

The role of early life nutrition's impact on relevant health outcomes across the lifespan laid the foundation for the field titled the developmental origins of health and disease. Studies in this area initially concentrated on nutrition and the risk of adverse cardio-metabolic and cancer outcomes. More recently the role of nutrition in early brain development and the subsequent influence of later mental health has become more evident. Scientific breakthroughs have elucidated two mechanisms behind long-term nutrient effects on the brain, including the existence of critical periods for certain nutrients during brain development and nutrient-driven epigenetic modifications of chromatin. While multiple nutrients and nutritional conditions have the potential to modify brain development, iron can serve as a paradigm to understand both mechanisms. New horizons in nutritional medicine include leveraging the mechanistic knowledge of nutrient-brain interactions to propose novel nutritional approaches that protect the developing brain through better timing of nutrient delivery and potential reversal of negative epigenetic marks. The main challenge in the field is detecting whether a change in nutritional status truly affects the brain's development and performance in human subjects. To that end, a strong case can be made to develop and utilise bioindicators of a nutrient's effect on the developing brain instead of relying exclusively on biomarkers of the nutrient's status.

Iron and Neurodevelopment in Preterm Infants: A Narrative Review

Iron is critical for brain development, playing key roles in synaptogenesis, myelination, energy metabolism and neurotransmitter production. NICU infants are at particular risk for iron deficiency due to high iron needs, preterm birth, disruptions in maternal or placental health and phlebotomy. If deficiency occurs during critical periods of brain development, this may lead to permanent alterations in brain structure and function which is not reversible despite later supplementation. Children with perinatal iron deficiency have been shown to have delayed nerve conduction speeds, disrupted sleep patterns, impaired recognition memory, motor deficits and lower global developmental scores which may be present as early as in the neonatal period and persist into adulthood. Based on this, ensuring brain iron sufficiency during the neonatal period is critical to optimizing neurodevelopmental outcomes and iron supplementation should be targeted to iron measures that correlate with improved outcomes.

Behavioral consequences at 5 y of neonatal iron deficiency in a low-risk maternal-infant cohort

BACKGROUND

Iron is critical to the developing brain, but fetal iron accretion is compromised by several maternal and pregnancy-related factors. Little consideration has been given to the long-term neurologic consequences of neonatal iron deficiency, especially in generally healthy, low-risk populations.

OBJECTIVE

We aimed to investigate the association between neonatal iron deficiency and neurologic development at 2 and 5 y of age.

DESIGN

We measured umbilical cord serum ferritin concentrations in the prospective maternal-infant Cork BASELINE (Babies after SCOPE: Evaluating the Longitudinal Impact Using Neurological and Nutritional Endpoints) Birth Cohort. Lifestyle and clinical data were collected from 15 weeks of gestation to 5 y of age. Standardized neurologic assessments were performed at 2 y [Bayley Scales of Infant Development/Child Behavior Checklist (CBCL)] and 5 y (Kaufman Brief Intelligence Test/CBCL).

RESULTS

Among 697 maternal-infant pairs, median (IQR) cord ferritin concentrations were 200.9 (139.0, 265.8) µg/L; 8% had neonatal iron deficiency (ferritin <76 µg/L). Using fully adjusted models, there was no association between neonatal iron deficiency and cognitive or behavioral outcomes at 2 or 5 y. We conducted an a priori sensitivity analysis in 306 high-risk children, selected using known risk factors for neonatal iron deficiency (smoking/obesity/cesarean section delivery/small-for-gestational age birth). In this high-risk subgroup, children with iron deficiency at birth (12%) had similar cognitive outcomes, but the behavioral assessments showed higher internalizing [9.0 (5.3, 12.0) compared with 5.0 (3.0, 10.0), P = 0.006; adjusted estimate (95% CI): 2.8 (0.5, 5.1), P = 0.015] and total [24.5 (15.3, 40.8) compared with 16.0 (10.0, 30.0), P = 0.009; adjusted estimate (95% CI): 6.6 (0.1, 13.1), P = 0.047] problem behavior scores at 5 y compared with those born iron sufficient.

CONCLUSIONS

We have demonstrated lasting behavioral consequences of neonatal iron deficiency in high-risk children from our generally healthy, low-risk maternal-infant cohort. Although larger investigations are warranted, this study provides strong association data to suggest that interventions and strategies targeting the fetal and neonatal period should be prioritized for the prevention of iron deficiency and associated neurologic consequences.

Sex differences in adult social, cognitive, and affective behavioral deficits following neonatal phlebotomy-induced anemia in mice

INTRODUCTION

Anemia is common in prematurely born infants due to blood loss resulting from frequent phlebotomies and may contribute to their neurobehavioral deficits. Preclinical models of phlebotomy-induced anemia (PIA) have revealed metabolic and genomic changes in multiple brain structures of young mice, yet the impact of neonatal PIA on early-life and adult behavior has not been assessed.

METHODS

The present study employed a range of behavioral measures in phlebotomized anemic neonatal mice to investigate short- and long-term neurodevelopmental effects. PIA from postnatal (P) days 3 to 14 caused sex-specific changes in social behavior, novelty preference, and anxiety at P17 that persisted into adulthood.

RESULTS

Our preclinical model suggests that PIA may contribute to acute and long-term behavioral and affective deficits and warrants further substantiation of the observed behavioral phenomena in larger samples.

CONCLUSIONS

We conclude that this model is a useful tool for beginning to better understand the lasting effect that early-life PIA might have on the developing brain. The differential impact of PIA on male and female subjects warrants further exploration for the development of appropriately targeted interventions.

Iron deficiency in pregnancy

Iron is essential for the function of all cells through its roles in oxygen delivery, electron transport, and enzymatic activity. Cells with high metabolic rates require more iron and are at greater risk for dysfunction during iron deficiency. Iron requirements during pregnancy increase dramatically, as the mother's blood volume expands and the fetus grows and develops. Thus, pregnancy is a condition of impending or existing iron deficiency, which may be difficult to diagnose because of limitations to commonly used biomarkers such as hemoglobin and ferritin concentrations. Iron deficiency is associated with adverse pregnancy outcomes, including increased maternal illness, low birthweight, prematurity, and intrauterine growth restriction. The rapidly developing fetal brain is at particular risk of iron deficiency, which can occur because of maternal iron deficiency, hypertension, smoking, or glucose intolerance. Low maternal gestational iron intake is associated with autism, schizophrenia, and abnormal brain structure in the offspring. Newborns with iron deficiency have compromised recognition memory, slower speed of processing, and poorer bonding that persist despite postnatal iron repletion. Preclinical models of fetal iron deficiency confirm that expected iron-dependent processes such as monoamine neurotransmission, neuronal growth and differentiation, myelination, and gene expression are all compromised acutely and long term into adulthood. This review outlines strategies to diagnose and prevent iron deficiency in pregnancy. It describes the neurocognitive and mental health consequences of fetal iron deficiency. It emphasizes that fetal iron is a key nutrient that influences brain development and function across the lifespan.

Irritability and Perceived Expressed Emotion in Adolescents With Iron Deficiency and Iron Deficiency Anemia: A Case-Control Study

The objective of this study was to assess the difference in irritability and perceived expressed emotion (EE) between adolescents with iron deficiency (ID) or iron deficiency anemia (IDA) and their healthy peers. In addition, we aimed to investigate the relationship between hemogram parameters, irritability, and perceived EE in adolescents with ID and IDA. The sample of this single-center cross-sectional case-control study consisted of 89 adolescents from 12 to 17 years of age. Of the participants, 19 had been diagnosed with ID, 31 had IDA, and 39 were healthy controls. Significant differences in the self-reported and parent-reported irritability scores were observed between the ID group and the control group and between the IDA group and the control group. There was also a significant difference in the subscale of irritability between the ID group and the control group. The difference between the IDA and control groups in the intrusiveness subscale was found to be significant as well. Adolescents with IDA and ID exhibited significantly perceived irritability compared with the control group. In terms of irritability, adolescents with IDA and ID revealed greater irritability than their healthy peers. The results of this study suggest that irritability and perceived EE should be investigated in cases of ID, whether with or without anemia. As chronic diseases may benefit substantially from psychiatric consultation, psychosocial evaluation and intervention should be considered a complementary treatment option in the management of ID and IDA.

A Comparison of the effects of preterm birth and institutional deprivation on child temperament

Both preterm birth and early institutional deprivation are associated with neurodevelopmental impairment-with both shared and distinctive features. To explore shared underlying mechanisms, this study directly compared the effects of these putative risk factors on temperament profiles in six-year-olds: Children born very preterm (<32 weeks gestation) or at very low birthweight (<1500 g) from the Bavarian Longitudinal Study (n = 299); and children who experienced >6 months of deprivation in Romanian institutions from the English and Romanian Adoptees Study (n = 101). The former were compared with 311 healthy term born controls and the latter with 52 nondeprived adoptees. At 6 years, temperament was assessed via parent reports across 5 dimensions: effortful control, activity, shyness, emotionality, and sociability. Very preterm/very low birthweight and postinstitutionalized children showed similarly aberrant profiles in terms of lower effortful control, preterm = -0.50, 95% CI [-0.67, -0.33]; postinstitutionalized = -0.48, 95% CI [-0.82, -0.14], compared with their respective controls. Additionally, postinstitutionalized children showed higher activity, whereas very preterm/very low birthweight children showed lower shyness. Preterm birth and early institutionalization are similarly associated with poorer effortful control, which might contribute to long-term vulnerability. More research is needed to examine temperamental processes as common mediators of negative long-term outcomes following early adversity.

Iron deficiency during pregnancy and lactation modifies the fatty acid composition of the brain of neonatal rats

Iron deficiency is common in pregnant and lactating women and is associated with reduced cognitive development of the offspring. Since iron affects lipid metabolism, the availability of fatty acids, particularly the polyunsaturated fatty acids required for early neural development, was investigated in the offspring of female rats fed iron-deficient diets during gestation and lactation. Subsequent to the dams giving birth, one group of iron-deficient dams was recuperated by feeding an iron-replete diet. Dams and neonates were killed on postnatal days 1, 3 and 10, and the fatty acid composition of brain and stomach contents was assessed by gas chromatography. Changes in the fatty acid profile on day 3 became more pronounced on day 10 with a decrease in the proportion of saturated fatty acids and a compensatory increase in monounsaturated fatty acids. Long-chain polyunsaturated fatty acids in the n-6 family were reduced, but there was no change in the n-3 family. The fatty acid profiles of neonatal brain and stomach contents were similar, suggesting that the change in milk composition may be related to the changes in the neonatal brain. When the dams were fed an iron-sufficient diet at birth, the effects of iron deficiency on the fatty acid composition of lipids in both dam's milk and neonates' brains were reduced. This study showed an interaction between maternal iron status and fatty acid composition of the offspring's brain and suggests that these effects can be reduced by iron repletion of the dam's diet at birth.

Umbilical Cord Serum Ferritin Concentration is Inversely Associated with Umbilical Cord Hemoglobin in Neonates Born to Adolescents Carrying Singletons and Women Carrying Multiples

BACKGROUND

It has been proposed that the fetus prioritizes iron for hemoglobin production over delivery to tissues. However, few studies have evaluated the interrelations between hemoglobin and multiple iron status biomarkers in umbilical cord blood. A full understanding is needed of how these parameters influence each other within cord blood to fully interpret iron and hematologic status at birth.

OBJECTIVES

We evaluated the determinants of neonatal hemoglobin and assessed the interrelations between hemoglobin, serum iron status indicators, and serum iron regulatory hormones in healthy neonates.

METHODS

This was an observational study that assessed umbilical cord hemoglobin (Hb), serum ferritin (SF), erythropoietin (EPO), soluble transferrin receptor (sTfR), serum iron, hepcidin, vitamin B-12, folate, IL-6, and CRP measured in 234 neonates born to adolescents or to women carrying multiples. Correlations between these indicators were evaluated and mediation models consistent with the observed significant determinants of cord Hb concentrations were developed.

RESULTS

A highly significant inverse association was found between cord SF and Hb concentrations that was not attributable to neonatal or maternal inflammation (as measured by IL-6 and CRP). The inverse association was present in the combined cohort, as well as in the adolescent and multiples cohorts independently. Mediation analyses found that EPO and hepcidin had significant indirect effects on cord Hb, associations that are explicable by mediation through SF and sTfR.

CONCLUSION

In contrast to observations made in older infants, a highly significant inverse association between Hb and SF, as well positive associations between Hb and both sTfR and EPO, were observed in umbilical cord blood from neonates born to adolescents or women carrying multiples. These findings, combined with review of the published literature, indicate a need for analysis of the relations between multiple parameters to assess iron and hematologic status at birth. These clinical trials were registered at clinicaltrials.gov as NCT01582802 (https://clinicaltrials.gov/ct2/show/NCT01582802) and NCT01019902 (https://clinicaltrials.gov/ct2/show/NCT01019902).

A systematic literature review of the relation between iron status/anemia in pregnancy and offspring neurodevelopment

BACKGROUND

The fetal brain starts developing early and animal studies have suggested that iron plays several roles for the development, but results from epidemiological studies investigating associations between gestational iron and offspring neurodevelopment are inconsistent.

OBJECTIVE

To systematically examine results from observational studies and RCTs on gestational iron and offspring neurodevelopment, with focus on the importance of four domains: iron status indicators, exposure timing, neurodevelopmental outcomes, and offspring age.

METHODS

PRISMA guidelines were followed. Embase, PsychInfo, Scopus, and The Cochrane library were searched in September 2017 and February 2018. Overall, 3307 articles were identified and 108 retrieved for full-text assessment. Pre-specified eligibility criteria were used to select studies and 27 articles were included;19 observational and 8 RCTs.

RESULTS

Iron status in pregnancy was associated with offspring behavior, cognition, and academic achievement. The direction of associations with behavioral outcomes were unclear and the conclusions related to cognition and academic achievement were based on few studies, only. Little evidence was found for associations with motor development. Observed associations were shown to persist beyond infancy into adolescence, and results depended on iron status indicator type but not on the timing of exposure.

CONCLUSION

We conclude that there is some evidence that low pregnancy iron, possibly particularly in the 3rd trimester, may be associated with adverse offspring neurodevelopment. As most previous research used Hemoglobin, inferring results to iron deficiency should be done with caution. No conclusions could be reached regarding associations beyond early childhood, and supplementation with iron during pregnancy did not seem to influence offspring neurodevelopment.

Nutritional influences on brain development

There is increasing evidence from preclinical and human studies that nutrition in the late foetal and early neonatal period has a significant impact on neurodevelopment across the lifespan. Certain nutrients have particularly large effects in this time period, and their deficits cause greater long-term risk. The mechanisms by which nutrients influence early brain growth and the sensitive periods for when certain nutrients should be provided are being elucidated. Assessments of nutritional status that index brain growth and predict long-term development are important to assess the efficacy of early life nutritional therapies.

CONCLUSION

Optimizing nutrition during foetal and early postnatal life is a golden opportunity to impact neurodevelopment and brain function across the lifespan.

Atypical fetal development: Fetal alcohol syndrome, nutritional deprivation, teratogens, and risk for neurodevelopmental disorders and psychopathology

Accumulating evidence indicates that the fetal environment plays an important role in brain development and sets the brain on a trajectory across the life span. An abnormal fetal environment results when factors that should be present during a critical period of development are absent or when factors that should not be in the developing brain are present. While these factors may acutely disrupt brain function, the real cost to society resides in the long-term effects, which include important mental health issues. We review the effects of three factors, fetal alcohol exposure, teratogen exposure, and nutrient deficiencies, on the developing brain and the consequent risk for developmental psychopathology. Each is reviewed with respect to the evidence found in epidemiological and clinical studies in humans as well as preclinical molecular and cellular studies that explicate mechanisms of action.

Iron-mediated oxidative cell death is a potential contributor to neuronal dysfunction induced by neonatal hemolytic hyperbilirubinemia

The review article discusses current knowledge of iron-mediated oxidative cell death (ferroptosis) and its potential role in the pathogenesis of neuronal dysfunction induced by neonatal hemolytic hyperbilirubinemia. The connection between metabolic conditions related to hemolysis (iron and bilirubin overload) and iron-induced lipid peroxidation is highlighted. Neurotoxicity of iron and bilirubin is associated with their release from destructed erythrocytes in response to hemolytic disease. Iron overload initiates lipid peroxidation through the reactive oxygen species production resulting to oxidative damage to cells. Excessive loading of immature brain cells by iron-induced formation of reactive oxygen species contributes to the development of various neurodevelopmental disorders. The causal relationship between iron overload and susceptibility of brain cells to oxidative damage by ferroptosis appears to be associated not only with the amount of redox-active iron involved in oxidative cell damage but also with the degree of maturity of the neonatal brain. Neuronal dysfunction induced by neonatal hemolytic disease can represent a specific model of ferroptosis. The mechanism by which iron overload triggers ferroptosis is not completely explained. However, hemolysis of neonatal red blood cells appears to be a determining factor. Potential therapeutic strategy with iron-chelating agents to inhibit ferroptosis has a promising future in postnatal care.

Biomarkers of Nutrition for Development (BOND)-Iron Review

This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health.The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation.

Associations Among Infant Iron Deficiency, Childhood Emotion and Attention Regulation, and Adolescent Problem Behaviors

This study examined whether iron deficiency (ID) in infancy contributes to problem behaviors in adolescence through its influence on poor regulatory abilities in childhood. Chilean infants (N = 1,116) were studied when there was no national program for iron fortification (1991-1996), resulting in high rates of ID (28%) and iron-deficiency anemia (IDA, 17%). Infants (54% male) were studied at childhood (Mage  = 10 years) and adolescence (Mage  = 14 years). IDA in infancy was related to excessive alcohol use and risky sexual behavior in adolescence through its effect on poor emotion regulation in childhood. Attentional control deficits at age 10 were also related to both infant IDA and heightened risk taking in adolescence. Findings elucidate how poor childhood regulatory abilities associated with infant IDA compromise adjustment in adolescence.

Approaches for Reducing the Risk of Early-Life Iron Deficiency-Induced Brain Dysfunction in Children

Iron deficiency is the most common micronutrient deficiency in the world. Women of reproductive age and young children are particularly vulnerable. Iron deficiency in late prenatal and early postnatal periods can lead to long-term neurobehavioral deficits, despite iron treatment. This may occur because screening and treatment of iron deficiency in children is currently focused on detection of anemia and not neurodevelopment. Anemia is the end-stage state of iron deficiency. The brain becomes iron deficient before the onset of anemia due to prioritization of the available iron to the red blood cells (RBCs) over other organs. Brain iron deficiency, independent of anemia, is responsible for the adverse neurological effects. Early diagnosis and treatment of impending brain dysfunction in the pre-anemic stage is necessary to prevent neurological deficits. The currently available hematological indices are not sensitive biomarkers of brain iron deficiency and dysfunction. Studies in non-human primate models suggest that serum proteomic and metabolomic analyses may be superior for this purpose. Maternal iron supplementation, delayed clamping or milking of the umbilical cord, and early iron supplementation improve the iron status of at-risk infants. Whether these strategies prevent iron deficiency-induced brain dysfunction has yet to be determined. The potential for oxidant stress, altered gastrointestinal microbiome and other adverse effects associated with iron supplementation cautions against indiscriminate iron supplementation of children in malaria-endemic regions and iron-sufficient populations.

Iron Nutriture of the Fetus, Neonate, Infant, and Child

Iron is a key nutrient and is essential for the developing fetus, neonate, infant, and child. Iron requirements are high during early stages of life because it is critically important for the production of new red blood cells and muscle cells as well as brain development. Neonates, infants, and children obtain iron from dietary sources including breast milk (lactoferrin) and heme- and non-heme-containing foods. Iron deficiency (ID) is the most common micronutrient deficiency in children and pregnant women worldwide. ID and iron deficiency anemia (IDA) can affect growth and energy levels as well as motor and cognitive performance in the developing child. The fetus is completely dependent on maternal iron crossing through the placenta and, although it is generally well protected against deficiency at birth, ID in mothers can increase the risk of ID and IDA in their children as early as 4 months. This review will discuss the uses of iron, iron requirements, and the sources of iron from conception through childhood. In addition, it will describe the prevalence and clinical manifestations of ID and IDA in children and discuss recommendations for iron supplementation of children and pregnant women.

Infant iron deficiency, child affect, and maternal unresponsiveness: Testing the long-term effects of functional isolation

Children who are iron deficient (ID) or iron-deficient anemic (IDA) have been shown to seek and receive less stimulation from their caregivers, contributing to functional isolation. Over time, the reduced interactions between child and caregiver are thought to interfere with the acquisition of normative social competencies and adversely affect the child's development. The current study examined functional isolation in children who were ID or IDA in infancy in relation to social difficulties in middle childhood and problem behaviors in adolescence. Using a sample of 873 Chilean children, 45% of whom were ID or IDA in infancy, structural equation modeling results indicated that infant IDA was associated with children's dull affect and social reticence at age 5, which were related to mothers' unresponsiveness and understimulation. Mothers' limited responsiveness and stimulation were, in turn, related to children's peer rejection at age 10, which further linked to problem behaviors and associating with deviant peers at adolescence. Findings support the functional isolation hypothesis and suggest that early limited caregiver responsiveness and stimulation contribute to long-term social difficulties in adolescents who were iron-deficient anemic in infancy. (PsycINFO Database Record

In rats gestational iron deficiency does not change body fat or hepatic mitochondria in the aged offspring

Mitochondrial dysfunction and resulting changes in adiposity have been observed in the offspring of animals fed a high fat (HF) diet. As iron is an important component of the mitochondria, we have studied the offspring of female rats fed complete (Con) or iron-deficient (FeD) rations for the duration of gestation to test for similar effects. The FeD offspring were ~12% smaller at weaning and remained so because of a persistent reduction in lean tissue mass. The offspring were fed a complete (stock) diet until 52 weeks of age after which some animals from each litter were fed a HF diet for a further 12 weeks. The HF diet increased body fat when compared with animals fed the stock diet, however, prenatal iron deficiency did not change the ratio of fat:lean in either the stock or HF diet groups. The HF diet caused triglyceride to accumulate in the liver, however, there was no effect of prenatal iron deficiency. The activity of the mitochondrial electron transport complexes was similar in all groups including those challenged with a HF diet. HF feeding increased the number of copies of mitochondrial DNA and the prevalence of the D-loop mutation, however, neither parameter was affected by prenatal iron deficiency. This study shows that the effects of prenatal iron deficiency differ from other models in that there is no persistent effect on hepatic mitochondria in aged animals exposed to an increased metabolic load.

Neurodevelopment: The Impact of Nutrition and Inflammation During Infancy in Low-Resource Settings

Infancy and early childhood (ie, birth through age 24 months) represent a period of life with both exquisite opportunity and vulnerability for neurodevelopment. This is due to rapid brain development, both anatomic and functional, as well as to high nutrient requirements during a time of dependence on human milk and complementary foods. Complex interactions exist among nutrition, social, and physical environments and exposures. The newborn brain also reflects maternal exposures that occurred as the product of many interacting forces during gestation. Connections between nutrient use and acute and chronic inflammation are increasingly recognized, but the evidence base linking both nutrition and inflammation to neurodevelopment is relatively modest and quite limited for this young age group specifically. This article provides an overview of key interactions of nutritional requirements relevant to brain development and function; nutritional vulnerabilities related to maternal nutritional status and function; and the impact of environmental exposures and inflammation on nutrient homeostasis and neurodevelopment during this critical developmental window.

Maternal Iron Status in Pregnancy and Long-Term Health Outcomes in the Offspring

Iron is an essential micronutrient and is important not only in carrying oxygen but also to the catalytic activity of a variety of enzymes. In the fetus, it is vital to the synthesis of hemoglobin and in brain development. Iron deficiency (ID) anemia in pregnancy is a common problem, even in high-income country settings. Around 50% of pregnant women worldwide are anemic, with at least half of this burden due to ID. Iron supplements are widely recommended and used during pregnancy globally. However, the evidence on the extent of benefit they contribute to the offspring's health is not well established, and their routine use has its side effects and drawbacks. Dietary iron intake is difficult to assess accurately and it is unlikely to be sufficient to meet the demands of pregnancy if women start with inadequate body iron stores at conception. Evidence from experimental animal models suggests that maternal ID during pregnancy is associated with fetal growth restriction, as well as offspring obesity and high blood pressure later in life. The possible biological mechanisms for this observed association may be due to ID-induced changes in placental structure and function, enzyme expression, nutrient absorption, and fetal organ development. However, such evidence is limited in human studies. Prenatal ID in experimental animal models also adversely affected the developing brain structures, neurotransmitter systems, and myelination resulting in acute brain dysfunction during the period of deficiency and persistence of various postnatal neurobehavioral abnormalities as well as persistent dysregulation of some genes into adult life after iron repletion pointing to the possibility of gene expression changes. The evidence from human population studies is limited and heterogeneous and more research is needed in the future, investigating the effects of ID in pregnancy on future offspring health outcomes.

Iron deficiency (ID) at both birth and 9 months predicts right frontal EEG asymmetry in infancy

This study considered effects of timing and duration of iron deficiency (ID) on frontal EEG asymmetry in infancy. In healthy term Chinese infants, EEG was recorded at 9 months in three experimental conditions: baseline, peek-a-boo, and stranger approach. Eighty infants provided data for all conditions. Prenatal ID was defined as low cord ferritin or high ZPP/H. Postnatal ID was defined as ≥ two abnormal iron measures at 9 months. Study groups were pre- and postnatal ID, prenatal ID only, postnatal ID only, and not ID. GLM repeated measure analysis showed a main effect for iron group. The pre- and postnatal ID group had negative asymmetry scores, reflecting right frontal EEG asymmetry (mean ± SE: -.18 ± .07) versus prenatal ID only (.00 ± .04), postnatal ID only (.03 ± .04), and not ID (.02 ± .04). Thus, ID at both birth and 9 months was associated with right frontal EEG asymmetry, a neural correlate of behavioral withdrawal and negative emotions.

Prenatal Iron Deficiency in Guinea Pigs Increases Locomotor Activity but Does Not Influence Learning and Memory

The objective of the current study was to determine whether prenatal iron deficiency induced during gestation in guinea pigs affected locomotor activity and learning and memory processes in the progeny. Dams were fed either iron-deficient anemic or iron-sufficient diets throughout gestation and lactation. After weaning, all pups were fed an iron-sufficient diet. On postnatal day 24 and 40, the pups’ locomotor activity was observed within an open-field test, and from postnatal day 25 to 40, their learning and memory processes were assessed within a Morris Water Maze. The behavioural and cognitive tests revealed that the iron deficient pup group had increased locomotor activity, but solely on postnatal day 40, and that there were no group differences in the Morris Water Maze. In the general discussion, we propose that prenatal iron deficiency induces an increase in nervousness due to anxiety in the progeny, which, in the current study, resulted in an increase of locomotor activity.

Some of the experimental and clinical aspects of the effects of the maternal diabetes on developing hippocampus

Diabetes mellitus during pregnancy is associated with an increased risk of multiple congenital anomalies in progeny. There are sufficient evidence suggesting that the children of diabetic women exhibit intellectual and behavioral abnormalities accompanied by modification of hippocampus structure and function. Although, the exact mechanism by which maternal diabetes affects the developing hippocampus remains to be defined. Multiple biological alterations, including hyperglycemia, hyperinsulinemia, oxidative stress, hypoxia, and iron deficiency occur in pregnancies with diabetes and affect the development of central nervous system (CNS) of the fetus. The conclusion from several studies is that disturbance in glucose and insulin homeostasis in mothers and infants are major teratogenic factor in the development of CNS. Insulin and Insulin-like growth factor-1 (IGF-1) are two key regulators of CNS function and development. Insulin and IGF-1 receptors (IR and IGF1R, respectively) are distributed in a highly specific pattern with the high density in some brain regions such as hippocampus. Recent researches have clearly established that maternal diabetes disrupts the regulation of both IR and IGF1R in the hippocampus of rat newborn. Dissecting out the mechanisms responsible for maternal diabetes-related changes in the development of hippocampus is helping to prevent from impaired cognitive and memory functions in offspring.

The role of zinc and iron-folic acid supplementation on early child temperament and eating behaviors in rural Nepal: a randomized controlled trial

Child eating behaviors play an important role in nutrient intake, ultimately affecting child growth and later outcomes in adulthood. The study assessed the effects of iron-folic acid and zinc supplementation on child temperament and child eating behaviors in rural Nepal. Children (N = 569) aged 4–17 months in Sarlahi district, southern Nepal were randomized to receive daily supplements of placebo, iron-folic acid, zinc, or zinc plus iron-folic acid and followed for approximately 1 year. At baseline and four follow-up visits mothers completed questionnaires including information on demographic characteristics and child temperament and eating behaviors. The main effects of zinc and iron-folic acid supplementation on temperament and eating behaviors were assessed through crude and adjusted differences in mean cumulative score changes between visits 1 and 5. The adjusted rate-of-change for these outcomes was modeled using generalized estimating equations. Mean changes in temperament scores and in eating behavior scores between visits 1 and 5 were not significant in either the zinc or non-zinc group. Children in the iron-folic acid group increased temperament scores by 0.37 points over 5 visits (95% CI 0.02, 0.7), which was not significant after adjustment. Neither the adjusted rate-of-change in temperament scores between zinc and non-zinc (β = −0.03, 95% CI −0.3, 0.2) or iron-folic acid and non-iron-folic acid (β = 0.08, 95% CI −0.2, 0.3) were significantly different. Adjusted rate of change analysis showed no significant difference between zinc and non-zinc (β = −0.14, 95% CI −0.3, 0.04) or between iron and non-iron eating behavior scores (β = −0.11, 95% CI −0.3, 0.1). Only among children with iron-deficiency anemia at baseline was there a significant decrease in eating behavior score, indicating better eating behaviors, when supplemented with zinc (β = −0.3, 95% CI −0.6, −0.01), Ultimately, this effect of zinc on eating behaviors was the only effect we observed after approximately one year of micronutrient supplementation.

Fetal iron deficiency and genotype influence emotionality in infant rhesus monkeys

BACKGROUND

Anemia during the third trimester of fetal development affects one-third of the pregnancies in the United States and has been associated with postnatal behavioral outcomes. This study examines how fetal iron deficiency (ID) interacts with the fetal monoamine oxidase A (MAOA) genotype. MAOA metabolizes monoamine neurotransmitters. MAOA polymorphisms in humans affect temperament and modify the influence of early adverse environments on later behavior.

OBJECTIVE

The aim of the study was to advance translation of developmental ID research in animal models by taking into account genetic factors that influence outcomes in human populations.

METHODS

Male infant rhesus monkeys 3-4 mo old born to mothers fed an ID (10 ppm iron) diet were compared with controls (100 ppm iron). Infant monkeys with high- or low-transcription rate MAOA polymorphisms were equally distributed between diet groups. Behavioral responses to a series of structured experiences were recorded during a 25-h separation of the infants from their mothers.

RESULTS

Infant monkeys with low-transcription MAOA polymorphisms more clearly demonstrated the following ID effects suggested in earlier studies: a 4% smaller head circumference, a 39% lower cortisol response to social separation, a 129% longer engagement with novel visual stimuli, and 33% lesser withdrawal in response to a human intruder. The high MAOA genotype ID monkeys demonstrated other ID effects: less withdrawal and emotionality after social separation and lower "fearful" ratings.

CONCLUSION

MAOA × ID interactions support the role of monoamine neurotransmitters in prenatal ID effects in rhesus monkeys and the potential involvement of common human polymorphisms in determining the pattern of neurobehavioral effects produced by inadequate prenatal nutrition.

Striking while the iron is hot: Understanding the biological and neurodevelopmental effects of iron deficiency to optimize intervention in early childhood

Prenatal and early postnatal iron deficiency (ID) is associated with long-term neurobiological alterations and disruptions in cognitive, social, and behavioral development. Early life ID is particularly detrimental as this is a period of rapid neurodevelopment. Even after iron supplementation, cognitive and social disruptions often persist in formerly iron deficient individuals. Observational studies of the acute and long-term effects of early life ID yield different results based on the timing of ID. Further, intervention studies demonstrate some improvement for certain domains but still show residual effects years later, which are dependent on the timing of ID and treatment. This review will cover the effects of ID during infancy and early childhood on brain structure and function, cognition, and behavior in relation to preclinical models of ID and sensitive periods of human brain development.

Issues in the timing of integrated early interventions: contributions from nutrition, neuroscience, and psychological research

A central issue when designing multidimensional biological and psychosocial interventions for children who are exposed to multiple developmental risks is identification of the age period(s) in which such interventions will have the strongest and longest lasting effects (sensitive periods). In this paper, we review nutritional, neuroscientific, and psychological evidence on this issue. Nutritional evidence is used to identify nutrient-sensitive periods of age-linked dimensions of brain development, with specific reference to iron deficiency. Neuroscience evidence is used to assess the importance of timing of exposures to environmental stressors for maintaining neural, neuroendocrine, and immune systems integrity. Psychological evidence illustrates the sensitivity of cognitive and social-emotional development to contextual risk and protective influences encountered at different ages. Evidence reviewed documents that the early years of life are a sensitive period when biological or psychosocial interventions or exposure to risk or protective contextual influences can produce unique long-term influences upon human brain, neuroendocrine, and cognitive or psychosocial development. However, the evidence does not identify the early years as the sole sensitive time period within which to have a significant influence upon development. Choice of age(s) to initiate interventions should be based on what outcomes are targeted and what interventions are used.

Association of hair iron levels with creativity and psychological variables related to creativity

Creativity generally involves the conception of original and valuable ideas. Previous studies have suggested an association between creativity and the dopaminergic system, and that physical activity facilitates creativity. Iron plays a key role in the dopaminergic system and physical activity. Here, we newly investigated the associations between hair iron levels and creativity, dopamine-related traits and states [novelty seeking, extraversion, and vigor (motivational state)], as well as the physical activity level. In the present study, we addressed this issue by performing a hair mineral analysis to determine iron levels and a behavioral creativity test of divergent thinking and related psychological measures among young adults (254 men, 88 women; mean age 20.79 ± 2.03 years). Iron levels did not show any significant association with creativity but displayed significant positive associations with novelty seeking, extraversion, and physical activity level. These results may be partly congruent with the notion that iron plays a key role in the dopaminergic system and imply that iron is important for traits and physical activity, which facilitate creativity. Future interventional or longitudinal studies are warranted to identify any causal effects.

Molecular mechanisms of cognitive impairment in iron deficiency: alterations in brain-derived neurotrophic factor and insulin-like growth factor expression and function in the central nervous system

OBJECTIVE

The present review examines the relationship between iron deficiency and central nervous system (CNS) development and cognitive impairment, focusing on the cellular and molecular mechanisms related to the expression and function of growth factors, particularly the insulin-like growth factors I and II (IGF-I/II) and brain-derived neurotrophic factor (BDNF), in the CNS.

METHODS

Nutritional deficiencies are important determinants in human cognitive impairment. Among these, iron deficiency has the highest prevalence worldwide. Although this ailment is known to induce psychomotor deficits during development, the precise molecular and cellular mechanisms underlying these alterations have not been properly elucidated. This review summarizes the available information on the effect of iron deficiency on the expression and function of growth factors in the CNS, with an emphasis on IGF-I/II and BDNF.

RESULTS AND DISCUSSION

Recent studies have shown that specific growth factors, such as IGF-I/II and BDNF, have an essential role in cognition, particularly in processes involving learning and memory, by the activation of intracellular-signaling pathways involved in cell proliferation, differentiation, and survival. It is known that nutritional deficiencies promote reductions in systemic and CNS concentrations of growth factors, and that altered expression of these molecules and their receptors in the CNS leads to psychomotor and developmental deficits. Iron deficiency may induce these deficits by decreasing the expression and function of IGF-I/II and BDNF in specific areas of the brain.

Infant responsiveness, alertness, haemoglobin and growth in rural Sidama, Ethiopia

Several recent studies have supported relations between infant behaviour (alertness and responsiveness) and nutrition in addition to investigating infant behaviour within the context of changes in iron status over time. Existing research is typically limited to the investigation of the effects of a single vitamin or mineral, and no studies have been found that examined the influence that early alertness and responsiveness have on growth in early infancy, despite the fact that relations between behaviour and nutritional status may be bidirectional. The current study used a sample of Ethiopian infants and investigated anthropometrics, haemoglobin, the frequency of alertness and the frequency of responsiveness at 6 and 9 months of age. Six-month weight-for-age predicted 9-month frequency of alertness, while 6-month haemoglobin predicted 9-month frequency of responsiveness. Compared with responsive infants, non-responsive infants at 6 months remained more non-responsive at 9 months, although weight-for-age for both groups converged at 9 months. Results support relations between nutrition and behaviour (alertness and responsiveness) and provide evidence of a potentially useful tool (the Laboratory Temperament Assessment Battery) that was adapted to evaluate these relations in Ethiopia.

Impact on infants' cognitive development of antenatal exposure to iron deficiency disorder and common mental disorders

Objectives

The aim of this study was to examine the effects of antenatal exposure to iron deficiency anemia (IDA) and common mental disorders (CMD) on cognitive development of 6 months old infants in a developing country.

Methods

A prospective population-based study in a rural province in Vietnam, which enrolled pregnant women at 12–20 weeks gestation and followed them up with their infants until six months postpartum. Criteria for IDA were Hb <11 g/dL and serum ferritin <15 ng/mL. CMD symptoms were assessed by the Edinburgh Postnatal Depression Scale-Vietnam validation. Infant cognitive development was assessed by Bayley Scales of Infant and Toddler Development, 3^rd Ed. Path analyses were performed to determine the direct and indirect, partly or fully mediated, causal effects of the antenatal exposures.

Results

A total of 497 pregnant women were recruited, of those 378 women provided complete data which were included in the analyses. Statistically significant direct adverse effects of persistent antenatal IDA (estimated difference of −11.62 points; 95% CI −23.01 to −0.22) and antenatal CMD (−4.80 points; 95% CI: −9.40 to −0.20) on infant Bayley cognitive scores at six months were found. Higher birthweight, household wealth, and self-rated sufficient supply of breastmilk were associated with higher cognitive scores. Maternal age >30 years and primiparity had an indirect adverse effect on infants’ Bayley cognitive scores.

Conclusions

These findings suggest that antenatal IDA and CMD both have adverse effects on child cognitive development, which if unrecognized and unaddressed are likely to be lasting. It is crucial that both these risks are considered by policy makers, clinicians, and researchers seeking to improve child cognitive function in developing countries.

A delicate balance: Iron metabolism and diseases of the brain

Iron is the most abundant transition metal within the brain, and is vital for a number of cellular processes including neurotransmitter synthesis, myelination of neurons, and mitochondrial function. Redox cycling between ferrous and ferric iron is utilized in biology for various electron transfer reactions essential to life, yet this same chemistry mediates deleterious reactions with oxygen that induce oxidative stress. Consequently, there is a precise and tightly controlled mechanism to regulate iron in the brain. When iron is dysregulated, both conditions of iron overload and iron deficiencies are harmful to the brain. This review focuses on how iron metabolism is maintained in the brain, and how an alteration to iron and iron metabolism adversely affects neurological function.

Effect of iron deficiency anemia in pregnancy on child mental development in rural China

OBJECTIVE

To determine the impact of iron deficiency anemia (IDA) in pregnancy on young child development.

METHODS

A 2-year follow-up of 850 children born to women who participated in a double-blind cluster randomized controlled trial of prenatal micronutrient supplementation in western rural China. These women were randomly assigned to receive either daily folic acid, iron/folic acid (60 mg iron), or multiple micronutrients (with 30 mg iron) during pregnancy. Children were categorized into the prenatal-IDA and prenatal-non-IDA groups based on the mother's hemoglobin in the third trimester. Each group contained 3 subgroups based on mother's treatment: folic acid, iron/folic acid, and multiple micronutrients. Bayley scales of infant development were administered to the children to assess their development at 3, 6, 12, 18, and 24 months of age.

RESULTS

Compared with the prenatal-non-IDA group, the prenatal-IDA group showed a significantly lower mental development index at 12, 18, and 24 months of age. The adjusted mean difference was 5.8 (95% confidence interval [CI], 1.1-10.5), 5.1 (95% CI, 1.2-9.0), and 5.3 (95% CI, 0.9-9.7), respectively. Further analysis showed that the mental development indexes in the prenatal-IDA group and prenatal-non-IDA group were similar with supplementation of iron/folic acid but were significantly lower in the prenatal-IDA group with supplementation of folic acid or multiple micronutrients.

CONCLUSIONS

Prenatal IDA in the third trimester is associated with mental development of the child. However, prenatal supplementation with sufficient iron protects child development even when the woman's IDA was not properly corrected in pregnancy.

Iron status in toddlerhood predicts sensitivity to psychostimulants in children

OBJECTIVE

Iron deficiency is associated with impaired dopaminergic signaling and externalizing behavior. The authors examine, whether iron stores in toddlerhood influence later response to psychostimulants.

METHOD

Youth participating in a study monitoring the long-term safety of risperidone were included in this analysis if they had received psychostimulant monotherapy for at least 3 weeks and had a complete blood count obtained before psychostimulant treatment. Sensitivity to psychostimulants was defined based on the weight-adjusted dose during the 1st year of treatment. Regression analysis examined whether the hematological tests based on the characteristics of red blood cells were associated with sensitivity to psychostimulants.

RESULTS

A total of 29 participants (93% men; 76% Whites), primarily with ADHD (93%), comprised the current sample. The hematological tests were obtained, on average, 3 years before the initiation of psychostimulants monotherapy that occurred at 5.8 years of age and continued for a median of 0.85 years, at an average daily dose of 0.98 mg/kg (SD = 0.38) in methylphenidate equivalent. Compared with those who were poorly sensitive to psychostimulants, after adjusting for age, mean corpuscular volume was significantly higher in the highly and moderately psychostimulants sensitive groups.

CONCLUSIONS

If replicated, these findings suggest that more attention should be paid to optimizing body iron in early childhood.

Influence of prenatal iron deficiency and MAOA genotype on response to social challenge in rhesus monkey infants

Social and emotional behaviors are known to be sensitive to both developmental iron deficiency (ID) and monoamine oxidase A (MAOA) gene polymorphisms. In this study, male rhesus monkey infants deprived of dietary iron in utero were compared with iron sufficient (IS) controls (n = 10/group). Half of each group had low MAOA activity genotypes and half had high MAOA activity genotypes. A series of social response tests were conducted at 3-14 months of age. MAOA genotype influenced attention to a video of aggressive behavior, emotional expression (fear, grimace and sniff) in the social intruder test, social actions (displacement, grooming) in the social dyad test, and aggressive responses to a threatening picture. Interactions between MAOA and prenatal ID were seen in response to the aggressive video, in temperament ratings, in affiliative behavior in the social dyad test, in cortisol response in the social buffering test and in response to a social intruder and to pictures with social and nonsocial themes. In general, the effects of ID were dependent on MAOA genotype in terms of both direction and size of the effect. Nutrition/genotype interactions may shed new light on behavioral consequences of nutritional deprivation during brain development.

Long-term brain and behavioral consequences of early iron deficiency

Early iron deficiency not only affects brain and behavioral function during the period of iron deficiency, it persists long after treatment. The mechanisms include long-term alterations in dopamine metabolism, myelination, and hippocampal structure and function. Recent studies have demonstrated long-term genomic changes, which suggests the regulation of brain function is fundamentally altered.

Iron status at birth and at 4 weeks in preterm-SGA infants in comparison with preterm and term-AGA infants

OBJECTIVE

To determine the iron status at birth in preterm small for gestational age (SGA) in comparison with preterm appropriate for gestation (AGA) and term-AGA infants.

METHODS

Mother-infant pairs with gestation of < 37 weeks, both SGA, and preterm-AGA and term-AGA as control were enrolled. Maternal, cord blood and infant blood samples at 4 weeks were obtained for various iron indices - cord serum ferritin, proportion of infants with "low" serum ferritin, serum ferritin at 4 weeks and correlation among maternal and neonatal iron indices - hemoglobin,serum ferritin and total iron-binding capacity.

RESULTS

There were 50 mother-infant pairs in each group. Cord serum ferritin levels were less in preterm-SGA group as compared to preterm-AGA group (median [interquartile range]: 68 [30 113] vs. 120 [73 127], p = 0.002) and preterm-AGA had less cord ferritin than term-AGA (141 [63 259], p = 0.006). The proportion of the infants with "low" serum ferritin was more in preterm-SGA than in preterm-AGA (16 [32%] vs. 5 [10%], p = 0.01). The serum ferritin levels at follow-up were also less in preterm-SGA as compared to preterm-AGA (143.5 ± 101 vs. 235.1 ± 160, p = 0.004). Other cord blood iron indices and follow-up serum ferritin levels were similar. There was no correlation among various maternal and neonatal cord iron parameters.

CONCLUSIONS

Preterm-SGA infants have lesser total iron stores as compared to gestation-matched AGA infants, which is again lesser than term infants. Future studies can be planned to look at iron status at 12 months as well as their neurodevelopmental outcome.

Early iron deficiency has brain and behavior effects consistent with dopaminergic dysfunction

To honor the late John Beard's many contributions regarding iron and dopamine biology, this review focuses on recent human studies that test specific hypotheses about effects of early iron deficiency on dopamine system functioning. Short- and long-term alterations associated with iron deficiency in infancy can be related to major dopamine pathways (mesocortical, mesolimbic, nigrostriatal, tuberohypophyseal). Children and young adults who had iron deficiency anemia in infancy show poorer inhibitory control and executive functioning as assessed by neurocognitive tasks where pharmacologic and neuroimaging studies implicate frontal-striatal circuits and the mesocortical dopamine pathway. Alterations in the mesolimbic pathway, where dopamine plays a major role in behavioral activation and inhibition, positive affect, and inherent reward, may help explain altered social-emotional behavior in iron-deficient infants, specifically wariness and hesitance, lack of positive affect, diminished social engagement, etc. Poorer motor sequencing and bimanual coordination and lower spontaneous eye blink rate in iron-deficient anemic infants are consistent with impaired function in the nigrostriatal pathway. Short- and long-term changes in serum prolactin point to dopamine dysfunction in the tuberohypophyseal pathway. These hypothesis-driven findings support the adverse effects of early iron deficiency on dopamine biology. Iron deficiency also has other effects, specifically on other neurotransmitters, myelination, dendritogenesis, neurometabolism in hippocampus and striatum, gene and protein profiles, and associated behaviors. The persistence of poorer cognitive, motor, affective, and sensory system functioning highlights the need to prevent iron deficiency in infancy and to find interventions that lessen the long-term effects of this widespread nutrient disorder.

Identifying a window of vulnerability during fetal development in a maternal iron restriction model

It is well acknowledged from observations in humans that iron deficiency during pregnancy can be associated with a number of developmental problems in the newborn and developing child. Due to the obvious limitations of human studies, the stage during gestation at which maternal iron deficiency causes an apparent impairment in the offspring remains elusive. In order to begin to understand the time window(s) during pregnancy that is/are especially susceptible to suboptimal iron levels, which may result in negative effects on the development of the fetus, we developed a rat model in which we were able to manipulate and monitor the dietary iron intake during specific stages of pregnancy and analyzed the developing fetuses. We established four different dietary-feeding protocols that were designed to render the fetuses iron deficient at different gestational stages. Based on a functional analysis that employed Auditory Brainstem Response measurements, we found that maternal iron restriction initiated prior to conception and during the first trimester were associated with profound changes in the developing fetus compared to iron restriction initiated later in pregnancy. We also showed that the presence of iron deficiency anemia, low body weight, and changes in core body temperature were not defining factors in the establishment of neural impairment in the rodent offspring.Our data may have significant relevance for understanding the impact of suboptimal iron levels during pregnancy not only on the mother but also on the developing fetus and hence might lead to a more informed timing of iron supplementation during pregnancy.