Why iron deficiency is important in infant development

Dietary iron intake during early pregnancy and birth outcomes in a cohort of British women

BACKGROUND Iron deficiency during pregnancy is associated with adverse birth outcomes, particularly, if present during early gestation. Iron supplements are widely recommended during pregnancy, but evidence of their benefit in relation to infant outcomes is not established. This study was performed in the UK, where iron supplements are not routinely recommended during pregnancy, to investigate the association between iron intake in pregnancy and size at birth. METHODS From a prospective cohort of 1274 pregnant women aged 18-45 years, dietary intake was reported in a 24-h recall administered by a research midwife at 12-week gestation. Dietary supplement intake was ascertained using dietary recall and three questionnaires in the first, second and third trimesters. RESULTS Of the cohort of pregnant women, 80% reported dietary iron intake below the UK Reference Nutrient Intake of 14.8 mg/day. Those reported taking iron-containing supplements in the first, second and third trimesters were 24, 15 and 8%, respectively. Women with dietary iron intake >14.8 mg/day were more likely to be older, have a higher socioeconomic profile and take supplements during the first trimester. Vegetarians were less likely to have low dietary iron intake [odds ratio = 0.5, 95% confidence interval (CI): 0.4, 0.8] and more likely to take supplements during the first and second trimesters. Total iron intake, but not iron intake from food only, was associated with birthweight centile (adjusted change = 2.5 centiles/10 mg increase in iron, 95% CI: 0.4, 4.6). This association was stronger in the high vitamin C intake group, but effect modification was not significant. CONCLUSION There was a positive relationship between total iron intake, from food and supplements, in early pregnancy and birthweight. Iron intake, both from diet and supplements, during the first trimester of pregnancy was higher in vegetarians and women with a better socioeconomic profile.

Why nutritional iron deficiency persists as a worldwide problem

The earliest studies of food iron absorption employing biosynthetically incorporated radioisotopes were published in the 1950s. Wheat flour has been fortified with iron in Canada, the United Kingdom, and the United States since the 1940s. However, half a century later, nutritional iron deficiency (ID) is estimated to affect 1.5-2 billion people worldwide. The reasons for the apparently limited impact of health and nutrition policies aimed at reducing the prevalence of ID in developing countries are complex. They include uncertainty about the actual prevalence of ID, particularly in regions where malaria and other infections are endemic, failure of policy makers to recognize the relationships between ID and both impaired productivity and increased morbidity, concerns about safety and the risks to iron-sufficient individuals if mass fortification is introduced, and technical obstacles that make it difficult to add bioavailable iron to the diets of those at greatest risk. It is, however, likely that the next decade will see a marked reduction in the prevalence of ID worldwide. More specific assessment tools are being standardized and applied to population surveys. The importance of preventing ID during critical periods of the life cycle is receiving increased attention. Innovative approaches to the delivery of bioavailable iron have been shown to be efficacious. The importance of integrating strategies to improve iron nutrition with other health measures, and economic and social policies addressing poverty as well as trade and agriculture, are receiving increasing consideration.

HFE gene variants affect iron in the brain

Iron accumulation in the brain and increased oxidative stress are consistent observations in many neurodegenerative diseases. Thus, we have begun examination into gene mutations or allelic variants that could be associated with loss of iron homeostasis. One of the mechanisms leading to iron overload is a mutation in the HFE gene, which is involved in iron metabolism. The 2 most common HFE gene variants are C282Y (1.9%) and H63D (8.9%). The C282Y HFE variant is more commonly associated with hereditary hemochromatosis, which is an autosomal recessive disorder, characterized by iron overload in a number of systemic organs. The H63D HFE variant appears less frequently associated with hemochromatosis, but its role in the neurodegenerative diseases has received more attention. At the cellular level, the HFE mutant protein resulting from the H63D HFE gene variant is associated with iron dyshomeostasis, increased oxidative stress, glutamate release, tau phosphorylation, and alteration in inflammatory response, each of which is under investigation as a contributing factor to neurodegenerative diseases. Therefore, the HFE gene variants are proposed to be genetic modifiers or a risk factor for neurodegenerative diseases by establishing an enabling milieu for pathogenic agents. This review will discuss the current knowledge of the association of the HFE gene variants with neurodegenerative diseases: amyotrophic lateral sclerosis, Alzheimer's disease, Parkinson's disease, and ischemic stroke. Importantly, the data herein also begin to dispel the long-held view that the brain is protected from iron accumulation associated with the HFE mutations.

Infant Nutrition and 12 and 18 Months Secure Base Behavior: An Exploratory Study

A notable omission in studies of developmental links to early nutritional deficiencies is infant attachment. In those few studies investigating associations between infant nutrition and attachment, nutrition was defined solely by physical growth, and infants had moderate-severe growth retardation. In this study, we utilized multiple markers of infant nutrition. Our sample consisted of 172 12-month-old Peruvian infants and their mothers from low-income families, with a follow-up assessment on 77 infants at 18 months. Infants were not severely malnourished, but did have micronutrient deficiencies. Anthropometry, dietary intake, and iron status were used as measures of infant nutrition. Based on infant behavior in a structured laboratory situation, Q-sort techniques were used to rate three attachment markers: infant secure base behavior, interaction quality, and negative emotionality with mother. At 12 months, infant weight was positively related to interaction quality. At 18 months, infant iron status was positively related to secure base behavior. This pattern of findings remained even after statistically controlling for family socioeconomic status and maternal education. Our findings indicate that infant nutritional status is associated with markers of infant attachment and these associations are not restricted just to severely malnourished infants.

Case study on iron in mental development--in memory of John Beard (1947-2009)

Iron deficiency (ID) anemia is associated with poor neurocognitive development in infants and children. Depending on the stage of development at the time of deficiency, these adverse effects may be reversible. Recent investigations using sensitive measurements have confirmed that the deposition of iron in the brain varies according to brain region and age, and that dopamine-dependent behaviors are among the core deficits in ID. Dr John Beard (1947-2009) has been one of the leading scientists and pioneers in the area of iron and child development. His legacy to this area of science will grow through the continuation of his work by his co-workers and colleagues.

Psychomotor development in children with iron deficiency and iron-deficiency anemia

BACKGROUND

Iron deficiency and iron-deficiency anemia are the most common nutritional deficiencies in children, especially in developing countries. Iron-deficiency anemia in infancy is associated with impaired neurodevelopment. Studies have shown an association between iron deficiency without anemia and adverse effects on psychomotor development.

OBJECTIVE

To determine the effects of iron deficiency and iron-deficiency anemia on psychomotor development in childhood.

METHODS

. We evaluated psychomotor development in healthy children with iron deficiency and iron-deficiency anemia with the use of the Denver II Developmental Screening Test (DDST-II). If the child score was more than 90th percentile compared to children in the same age group, the test was scored as "delay" it was scored as a "caution" if the child score was between the 75th and 90th percentiles. The test result was interpreted as "normal," if there was no delay and only one "caution" for any item. If the child had one or more "delays" or more than two "cautions," the result was classified as "abnormal."

RESULTS

DDST-II scores were abnormal in 67.3% of subjects with iron-deficiency anemia, 21.6% of those with iron deficiency, and 15.0% of control subjects. The difference from the control group in the percentage of abnormal scores was significant for subjects with iron-deficiency anemia (p < .01) but not for those with iron deficiency (p = 0.203); p > .05. (p-value, post-hoc comparison of 2 groups.)

CONCLUSIONS

Iron-deficiency anemia impaired psychomotor development during childhood. However, the evidence on the adverse effects of iron deficiency remains controversial. The Denver II Developmental Screening Test is a valuable test to detect early developmental delays, especially in infants with risk factors.

Fatores favoráveis à recuperação do quadro clínico de crianças anêmicas: um estudo exploratório

OBJETIVO: investigar a existência de aspectos do ambiente familiar de crianças anêmicas que possam ser considerados favoráveis à recuperação do quadro de anemia e ao desenvolvimento da linguagem. MÉTODOS: trata-se de um estudo de caso de crianças com anemia. As crianças (n = 11) foram submetidas anteriormente ao tratamento clínico e avaliação da linguagem. Após 12 meses, foram reavaliadas nos aspectos clínicos e da linguagem, acrescentando-se a investigação dos recursos do ambiente familiar. Deste grupo, foram selecionados três casos que refletem diferentes evoluções do quadro clínico da anemia e do desenvolvimento da linguagem, a fim de explorar as contribuições do ambiente familiar na melhora desses aspectos. RESULTADOS: a comparação das variáveis entre as crianças que obtiveram melhora ou não no tratamento medicamentoso mostra diferença estatisticamente nos valores de hemoglobina e tempo de aleitamento materno (p<0,05). A análise dos três casos revela que a situação ambiental pode ser agravante do quadro clínico da criança. CONCLUSÕES: a qualidade dos recursos domiciliares, o tempo de aleitamento materno e as práticas parentais em relação à criança podem ter contribuído para a adequada recuperação da criança nos aspectos focalizados.

Critical issues in setting micronutrient recommendations for pregnant women: an insight

The European Micronutrient Recommendations Aligned (EURRECA) Network aims to provide standardized approaches to reveal and beneficially influence variability within the European Union in micronutrient recommendations for vulnerable population groups. Characterization of the 'vulnerability' together with the 'variability' of micronutrient needs represents the first step to creating guidelines for setting micronutrient recommendations within target populations. This paper describes some of the key factors and characteristics relevant to assess micronutrient requirements and formulate recommendations of micronutrients in pregnancy. Nutritional requirements during pregnancy increase to support fetal growth and development as well as maternal metabolism and tissue accretion. Micronutrients are involved in both embryonal and fetal organ development and overall pregnancy outcomes. Several factors may affect directly or indirectly fetal nourishment and the overall pregnancy outcomes, such as the quality of diet including intakes and bioavailability of micronutrients, maternal age, and the overall environment. The bioavailability of micronutrients during pregnancy varies depending on specific metabolic mechanisms because pregnancy is an anabolic and dynamic state orchestrated via hormones acting for both redirection of nutrients to highly specialized maternal tissues and transfer of nutrients to the developing fetus. The timing of prenatal intakes or supplementations of specific micronutrients is also crucial as pregnancy is characterized by different stages that represent a continuum, up to lactation and beyond. Consequently, nutrition during pregnancy might have long-lasting effects on the well-being of the mother and the fetus, and may further influence the health of the baby at a later age.

Iron supplements reduce the risk of iron deficiency anemia in marginally low birth weight infants

OBJECTIVE

Low birth weight infants are at risk for iron deficiency (ID). Most LBW infants have marginally low birth weight (MLBW, 2000-2500 g) and it is not known whether they benefit from iron supplements. The objective of this trial was to study the effects of iron supplementation in MLBW infants.

METHOD

In a randomized controlled trial, we assigned 285 healthy, MLBW infants to receive iron supplements at a dose of 0 (placebo), 1, or 2 mg/kg per day between 6 weeks and 6 months of age. Hemoglobin levels, ferritin levels, transferrin saturation, mean cell volume, and transferrin receptor levels were analyzed at 6 months. Growth and morbidity were monitored.

RESULTS

Iron supplementation resulted in significant dose-dependent effects on hemoglobin and all iron status indicators at 6 months. The prevalence of ID at 6 months was 36% in the placebo group, 8.2% in the 1 mg/kg per day group, and 3.8% in the 2 mg/kg per day group (P<.001). The prevalence rates of ID anemia (IDA) were 9.9%, 2.7%, and 0%, respectively (P=.004). Among infants who were exclusively breastfed at 6 weeks, the prevalence of IDA was 18% in the placebo group. There were no significant differences between groups in growth or morbidity.

CONCLUSIONS

MLBW infants have relatively high risks of ID and IDA, especially if they are breastfed. Iron supplementation at 2 mg/kg per day from 6 weeks to 6 months reduces this risk effectively, with no short-term adverse effects on morbidity or growth.

Nutrition and indigenous health in New Zealand

Within New Zealand, Maori experience a greater burden than non-Maori from childhood communicable diseases and from adult non-communicable diseases, for which malnutrition is recognised to have an important role in causality. The nutritional status of Maori is poorer than non-Maori. A larger proportion of Maori newborns are small for gestational age. Weight gain during the first 2 years of life is then more rapid than for non-Maori, and the proportion of Maori that are obese is higher than non-Maori through childhood and into adulthood. Across the age range from infancy to women of childbearing age, iron deficiency is more prevalent, and vitamin D status is poorer in Maori than non-Maori. Over the past two decades, the nutritional status of Maori has improved at birth and during childhood. The proportion of Maori infants small for gestational age and the mean body mass of Maori children aged 2-14 years have decreased. These improvements have been larger than in non-Maori. Further reduction in disparities in nutritional status between Maori and non-Maori must be a priority if the health status of New Zealand's population is to improve. The interventions must address the role that poverty plays in malnutrition, need to be rooted in local food systems and be community driven. If population health status is to improve, New Zealand must secure access to nutritious food for pregnant women, infants and children living in low-income families.

Brain iron metabolism and its perturbation in neurological diseases

Metal ions are of particular importance in brain function, notably iron. A broad overview of iron metabolism and its homeostasis both at the cellular level (involving regulation at the level of mRNA translation) and the systemic level (involving the peptide 'hormone' hepcidin) is presented. The mechanisms of iron transport both across the blood-brain barrier and within the brain are then examined. The importance of iron in the developing foetus and in early life is underlined. We then review the growing corpus of evidence that many neurodegenerative diseases (NDs) are the consequence of dysregulation of brain iron homeostasis. This results in the production of reactive oxygen species, generating reactive aldehydes, which, together with further oxidative insults, causes oxidative modification of proteins, manifested by carbonyl formation. These misfolded and damaged proteins overwhelm the ubiquitin/proteasome system, accumulating the characteristic inclusion bodies found in many NDs. The involvement of iron in Alzheimer's disease and Parkinson's disease is then examined, with emphasis on recent data linking in particular interactions between iron homeostasis and key disease proteins. We conclude that there is overwhelming evidence for a direct involvement of iron in NDs.

Neonatal period: linking best nutrition practices at birth to optimize maternal and infant health and survival

Delayed umbilical cord clamping, immediate skin-to-skin contact, and early initiation of breastfeeding have been shown to be simple, safe, and effective and should be implemented in all deliveries, with very few exceptions. Although these practices can also prevent death, their importance extends beyond survival and optimizes both short-and long-term neonatal and maternal health and nutrition. Their implementation requires that they be integrated with one another and included with other standard lifesaving care practices. Leveraging knowledge of efficacious interventions into high-quality programs with broad coverage is often the main obstacle to improving neonatal and maternal health in low-income countries. To achieve results at-scale, attention must be given to increasing access to scientific information supporting evidence-based practices and addressing the skills needed to implement the recommended practices; establishing and communicating global, national, and local policies and guidelines for implementation in conjunction with advocacy and synchronization with other maternal and neonatal care efforts; reorganizing delivery care services; and monitoring and evaluation. This will require international investments similar to those being made for other lifesaving neonatal interventions. Neonatal vitamin A supplementation, recommended for implementation in Asia, is controversial, and the evidence for and against this recommendation is reviewed.

Redox control of prion and disease pathogenesis

Imbalance of brain metal homeostasis and associated oxidative stress by redox-active metals like iron and copper is an important trigger of neurotoxicity in several neurodegenerative conditions, including prion disorders. Whereas some reports attribute this to end-stage disease, others provide evidence for specific mechanisms leading to brain metal dyshomeostasis during disease progression. In prion disorders, imbalance of brain-iron homeostasis is observed before end-stage disease and worsens with disease progression, implicating iron-induced oxidative stress in disease pathogenesis. This is an unexpected observation, because the underlying cause of brain pathology in all prion disorders is PrP-scrapie (PrP(Sc)), a beta-sheet-rich conformation of a normal glycoprotein, the prion protein (PrP(C)). Whether brain-iron dyshomeostasis occurs because of gain of toxic function by PrP(Sc) or loss of normal function of PrP(C) remains unclear. In this review, we summarize available evidence suggesting the involvement of oxidative stress in prion-disease pathogenesis. Subsequently, we review the biology of PrP(C) to highlight its possible role in maintaining brain metal homeostasis during health and the contribution of PrP(Sc) in inducing brain metal imbalance with disease progression. Finally, we discuss possible therapeutic avenues directed at restoring brain metal homeostasis and alleviating metal-induced oxidative stress in prion disorders.

The effects of early adversity on the adult and developing brain

PURPOSE OF REVIEW

Recent advances in neuroimaging methods have provided new ways of unravelling the complex interplay between genetic and environmental factors that influence functional brain development in the critical first years of life. This has allowed new insights into the effects that early adverse experience can exert on the brain later in life. We review recent progress in the characterization of those effects and underlying mechanisms through which adverse environment influences the neurocognitive development.

RECENT FINDINGS

Socioeconomic background may have a profound effect on structural and functional brain development, especially in the domains of language and prefrontal executive control. These effects are mediated by several factors: diet, quality of parental care, impoverished environment, prenatal exposure to toxic substances and so on. Other circumstances such as perinatal brain injury, early sensory deprivation or limb malformation may result in atypical functional organization of the brain and lasting cognitive impairment of certain functions. Early experience of maltreatment or institutionalized care may alter the development of the social brain, contributing to negative mental health outcomes, which may be partially reversed through early intervention programmes.

SUMMARY

Subsequent models of psychiatric disorder should take into account early risk factors and embrace developmental models at multiple levels of biological organization. There is a continuing need for the study of optimal environmental input during sensitive periods in brain development.

Metabolic response to iron deficiency in Saccharomyces cerevisiae

Iron is an essential cofactor for enzymes involved in numerous cellular processes, yet little is known about the impact of iron deficiency on cellular metabolism or iron proteins. Previous studies have focused on changes in transcript and proteins levels in iron-deficient cells, yet these changes may not reflect changes in transport activity or flux through a metabolic pathway. We analyzed the metabolomes and transcriptomes of yeast grown in iron-rich and iron-poor media to determine which biosynthetic processes are altered when iron availability falls. Iron deficiency led to changes in glucose metabolism, amino acid biosynthesis, and lipid biosynthesis that were due to deficiencies in specific iron-dependent enzymes. Iron-sulfur proteins exhibited loss of iron cofactors, yet amino acid synthesis was maintained. Ergosterol and sphingolipid biosynthetic pathways had blocks at points where heme and diiron enzymes function, whereas Ole1, the essential fatty acid desaturase, was resistant to iron depletion. Iron-deficient cells exhibited depletion of most iron enzyme activities, but loss of activity during iron deficiency did not consistently disrupt metabolism. Amino acid homeostasis was robust, but iron deficiency impaired lipid synthesis, altering the properties and functions of cellular membranes.

Metabolic crossroads of iron and copper

Interactions between the essential dietary metals, iron and copper, have been known for many years. This review highlights recent advances in iron-copper interactions with a focus on tissues and cell types important for regulating whole-body iron and copper homeostasis. Cells that mediate dietary assimilation (enterocytes) and storage and distribution (hepatocytes) of iron and copper are considered, along with the principal users (erythroid cells) and recyclers of red cell iron (reticuloendothelial macrophages). Interactions between iron and copper in the brain are also discussed. Many unanswered questions regarding the role of these metals and their interactions in health and disease emerge from this synopsis, highlighting extensive future research opportunities.

Research needed to strengthen science and programs for the control of iron deficiency and its consequences in young children

The purpose of this article is to highlight critical research needs for the effective prevention and control of iron deficiency and its consequences in children living in low-income countries. Four types of research are highlighted: The first involves scaling up interventions that we know are effective, namely iron supplementation of pregnant women, delayed cord clamping at delivery, immediate and exclusive breast-feeding, and continued exclusive breast-feeding for approximately 6 mo. The second entails evaluation research of alternative interventions that are likely to work, to find the most cost-effective strategies for a given social, economic, and epidemiological context. This research is especially needed to expand the implementation of appropriate complementary feeding interventions. In this area, research needs to be designed to provide causal evidence, to measure cost-effectiveness, and to measure potential effect modifiers. The third is efficacy research to discover promising practices where we lack proven interventions. Examples include how to detect infants younger than 6 mo who are at high risk of iron deficiency, efficacious and safe interventions for those young high-risk infants, and best protocols for the treatment of severe anemia. The fourth includes basic research to elucidate physiological processes and mechanisms underlying the risks and benefits of supplemental iron for children exposed to infectious diseases, especially malaria. Strategic research in all 4 areas will ensure that interventions to control pediatric iron deficiency are integrated into national programs and global initiatives to make pregnancy safer, reduce newborn deaths, and promote child development, health, and survival.

Iron metabolism, malaria, and other infections: what is all the fuss about?

This article briefly describes how iron lies at the center of a host-pathogen battle for nutrients and why there are many theoretical reasons to suspect that administration of supplemental iron might predispose to infection. This is supported by in vitro and small animal studies, but meta-analysis of human epidemiological and intervention studies has found little evidence for most disease outcomes. Supplemental iron does appear to increase susceptibility to malaria as measured by a variety of malariometric indices. However, even in malarious areas, iron appears beneficial in iron-deficient subjects. The concerns about iron supplementation programs for children seem to be confined to Sub-Saharan Africa and to areas of high malaria endemicity, where it will be necessary to adopt a cautious approach to supplementation based either on screening out iron-replete children or combining iron administration with effective disease-control strategies.

Setting the stage for child health and development: prevention of iron deficiency in early infancy

Iron deficiency is estimated to be the most common nutritional deficiency worldwide and is particularly persistent among infants and children. The high prevalence of anemia in 6- to 9-mo-old children raises the concern that birth iron stores in some infants are inadequate to sustain growth and development through the first 6 mo of life, and postnatal factors are contributing to early depletion of iron stores and development of anemia. At the same time, there are concerns about negative effects of excess iron in infants. Maternal iron status, infant birth weight and gestational age, as well as the timing of umbilical cord clamping at birth all contribute to the establishment of adequate total body iron at birth. Postnatally, feeding practices and growth rate are factors that will affect how quickly birth iron is depleted during the first 6 mo of life. Under conditions in which maternal iron status, birth weight, gestational age, and umbilical cord clamping time are optimal, and exclusive breast-feeding is practiced, infants should have adequate iron stores for the first 6-8 mo of life. Under suboptimal conditions, infants may not reach this goal and may need to be targeted for iron supplementation before 6 mo of age.

Iron deficiency in young children in low-income countries and new approaches for its prevention

Anemia resulting from severe iron deficiency (ID) is the most prevalent and widespread nutrition-related health problem in infants and young children in low-income countries and has proven very resistant to prevention through public health interventions. Accumulative evidence from animal and human studies suggests that such deficiencies are associated with large adverse effects on child cognitive and motor development. Therefore, effective interventions to improve iron status will have large health benefits. Action to reduce young child ID would benefit from overarching policy and programmatic guidance that informs decision makers about what to do, when to do it, and how to do it. The impetus for new approaches to prevent ID in young children reflects growing recognition of the need to intervene early and often and for better vehicles to deliver iron. Prevention of ID requires strong delivery systems that enhance consumer demand and promote compliance. When this occurs, the prevalence of anemia is greatly reduced.