A randomized trial of two levels of iron supplementation and developmental outcome in low birth weight infants

The Effects of Iron Administration on Anemia Development during the 7th and 21st Day of Life in Premature Newborns: A Prospective Cohort Study

Background and Objectives: The administration of iron to premature newborns is a common intervention aimed at preventing iron deficiency (ID). However, there is no consensus on the optimal timing and dosage for iron supplementation in this population. This study evaluates the effects and potential adverse outcomes of administering iron on the 7th and 21st days of life in premature infants. Materials and Methods: This research was conducted on 108 premature neonates at the "Louis Turcanu" Children's Emergency Clinical Hospital in Timisoara, Romania. The study population was divided into a control group of 48 newborns who did not receive iron supplementation and an intervention group of 60 newborns who did. The analysis utilized univariate and multivariate regression to examine binary outcomes. Results: The findings indicate that iron supplementation significantly increased the risk of anemia during the premature period at 21 days of life, as demonstrated by both univariate and multivariate regression analyses, with an odds ratio (OR) of 2.40 (95% CI, 1.01-5.68) and an adjusted odds ratio (AOR) of 2.75 (95% CI, 1.06-7.11), respectively. Contrary to expectations, iron supplementation did not significantly alter the risk of abnormal serum ferritin or iron levels at 21 days of life, according to the univariate analysis (p = 0.380 and p = 0.526, respectively). Conclusions: The observed increase in the risk of anemia without a corresponding improvement in the serum ferritin or iron levels suggests the need for further investigation into alternative strategies for iron supplementation in premature newborns.

Iron and DHA in Infant Formula Purchased in the US Fails to Meet European Nutrition Requirements

Requirements for iron and docosahexaenoic acid (DHA) content of infant formula varies by country. Powdered full-term infant formula purchase data from all major physical stores in the US between 2017-2019 were obtained from CIRCANA, Inc. Iron and DHA composition and scoop sizes for each formula were obtained from manufacturers. The equivalent liquid ounces of prepared formula were calculated. Average iron and DHA content were compared between formula types and to both US and European formula composition requirements. These data represent 55.8 billion ounces of formula. The average iron content of all formula purchased was: 1.80 mg/100 kcal. This iron concentration is within the FDA regulations. However, it exceeds the maximum allowable iron concentration of infant formula (Stage 1) set by the European Commission of 1.3 mg/100 kcal. A total of 96% of formula purchased had an iron concentration of >1.3 mg/100 kcal. DHA is not a required ingredient in US formulas. The average DHA content of all formula purchased was: 12.6 mg/100 kcal. This DHA concentration is far below the minimum required DHA concentrations of infant formula (Stage 1) and follow-on formula (Stage 2) set by the European Commission of 20 mg/100 kcal. These are novel insights into the iron and DHA intake of formula-fed infants in the US. As international infant formulas have entered the US market due to the formula shortage, parents and providers need to be aware of regulatory differences in formula nutrient composition.

Enteral Iron Supplementation in Preterm or Low Birth Weight Infants: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Iron is needed for growth and development of infants globally, but preterm and low birth weight (LBW) infants are at risk for severe iron deficiencies. To assess the effect of enteral iron supplementation on mortality, morbidity, growth, and neurodevelopment outcomes in preterm or LBW infants fed human milk. Secondary objectives were to assess the effect on biomarkers and dose and timing.

METHODS

Data sources include PubMed, Embase and Cochrane Library databases to March 16, 2021. Study Selection includes controlled or quasi experimental study designs. Two reviewers independently extracted data.

RESULTS

Eight trials (eleven reports; 1093 participants, 7 countries) were included. No trials reported mortality. At latest follow-up, there was little effect on infection (very low certainty evidence, 4 studies, 401 participants, relative risk [RR] 0.98, 95% confidence interval [95% CI] 0.56 to 1.73, I2 = 0.00%) and necrotising enterocolitis (3 studies, 375 participants, RR 1.47, 95% CI 0.68 to 3.20, I2 = 0.00%). There was an increase in linear growth (length) (moderate certainty evidence, 3 studies, 384 participants, mean difference 0.69 cm, 95% CI 0.01 to 1.37, I2 = 0%) but little effect on weight, head circumference, or cognitive development. There was an improvement in anemia (moderate certainty evidence, 2 studies, 381 participants, RR 0.25, 95% CI 0.10 to 0.62, I2 = 0.00%) but no effect on serum ferritin. Limitations include heterogeneity in the included studies.

CONCLUSIONS

There are important benefits for human milk-fed preterm and LBW infants from enteral iron supplementation. However, more randomized control trials are required to improve the certainty of evidence.

Iron Supplementation Is Associated with Improvement of Motor Development, Hemoglobin Level, and Weight in Preterm Infants during the First Year of Life in China

Iron supplementation is recommended for preterm infants due to impaired iron endowment. However, the health outcomes of this recommendation remain controversial. Thus, this study aimed to determine the association of iron supplementation with neurobehavioral development, hemoglobin (Hb), and anthropometric characteristics in preterm infants. A retrospective cohort design was applied to collect data from 1568 preterm infants at 0–3 months of corrected age (mo CA) from a hospital in South China. Infants were categorized into a 3-month iron supplementation group (IG, n = 697) or a control group (CG, n = 871) according to medical records, and then followed through to 12 mo CA. Data on neurobehavioral development, anthropometry, Hb level, history of diseases, and nutrition were collected at 3, 6, and 12 mo CA. The results showed that, compared with the CG, iron supplementation was positively related to improved gross motor skills and weight at 6 mo CA (β = 1.894, β = 5.322) and 12 mo CA (β = 4.019, β = 6.830) and fine motor skills at 12 mo CA (β = 1.980), after adjustment for confounding factors including illness, nutritional supplements, and diet. Iron supplementation was also related to elevated Hb levels and its increase at 3 mo CA (β = 2.196, β = 3.920) and 6 mo CA (β = 3.011, β = 7.259). In conclusion, iron supplementation for 3 months in Chinese preterm infants is positively associated with improved motor development, elevated Hb levels, and higher body weight during the first year of life.

Nutrient supplementation for prevention of viral respiratory tract infections in healthy subjects: A systematic review and meta-analysis

It remains uncertain as to whether nutrient supplementation for the general population considered healthy could be useful in the prevention of RTIs, such as COVID-19. In this systematic review and meta-analysis, the evidence was evaluated for primary prevention of any viral respiratory tract infection (RTI) such as SARS-CoV-2, through supplementation of nutrients with a recognized role in immune function: multiple micronutrients, vitamin A, folic acid, vitamin B12, C, D, E, beta-carotene, zinc, iron and long-chain polyunsaturated fatty acids. The search produced 15,163 records of which 93 papers (based on 115 studies) met the inclusion criteria, resulting in 199,055 subjects (191,636 children and 7,419 adults) from 37 countries. Sixty-three studies were included in the meta-analyses, which was performed for children and adults separately. By stratifying the meta-analysis by world regions, only studies performed in Asia showed a significant but heterogeneous protective effect of zinc supplementation on RTIs (RR 0.86, 95% CI 0.7-0.96, I²  = 79.1%, p = .000). Vitamin D supplementation in adults significantly decreased the incidence of RTI (RR 0.89, 95% CI 0.79-0.99, p = .272), particularly in North America (RR 0.82 95% CI 0.68-0.97), but not in Europe or Oceania. Supplementation of nutrients in the general population has either no or at most a very limited effect on prevention of RTIs. Zinc supplementation appears protective for children in Asia, whilst vitamin D may protect adults in the USA and Canada. In 10/115 (8.7%) studies post-hoc analyses based on stratification for nutritional status was performed. In only one study zinc supplementation was found to be more effective in children with low zinc serum as compared to children with normal zinc serum levels.

Reticulocyte hemoglobin content changes after treatment of anemia of prematurity

BACKGROUND

Iron deficiency during infancy is associated with poor neurological development, but iron overload causes severe complications. Appropriate iron supplementation is therefore vital. Reticulocyte hemoglobin content (RET-He) provides a real-time assessment of iron status and chracterezes hemoglobin synthesis in preterm infants. However, the existing literature lacks detailed reports assessing chronological changes in RET-He. The aim of this study was to assess the chronological changes in RET-He during oral iron dietary supplementation, and concomitant therapy with recombinant human erythropoietin (rHuEPO) in preterm very low birthweight infants.

METHODS

Very low birthweight infants, admitted to our neonatal intensive care unit were analyzed retrospectively. Hemoglobin (Hb), reticulocyte percentage (Ret), mean corpuscular volume, RET-He, serum iron (Fe), and serum ferritin were recorded. Data at birth (T0), the initial day of rHuEPO therapy (T1), the initial day of oral iron supplementation (T2), 1-2 weeks (T3), 3-4 weeks (T4), 5-6 weeks (T5), and 7-8 weeks (T6) from the initial day of oral iron supplementation were extracted, and their changes over time were examined.

RESULTS

Reticulocyte hemoglobin content was highest at birth and declined rapidly thereafter, especially after starting rHuEPO therapy. There was no upward trend in RET-He after the initiation of oral iron supplementation, with a slower increase during 5-6 weeks after the initiation of iron therapy.

CONCLUSIONS

During the treatment of anemia of prematurity, low RET-He levels may be prolonged. Anemia of prematurity should therefore be assessed and treated on a case-by-case basis, while considering the iron metabolic capacity of preterm infants.

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.

Intestinal Microbiome in Preterm Infants Influenced by Enteral Iron Dosing

OBJECTIVES

The aim of the study was to compare the intestinal microbiome in very low birth weight (VLBW) infants who received different enteral iron supplementation (EIS) doses.

STUDY DESIGN

Longitudinal stool collection in 80 VLBW infants were conducted up to 2 months postnatally in a prospective study. The 16S rRNA regions V4 was used to calculate microbiome compositions and the Piphillin software was used for bacterial functional prediction. Linear mixed effect models and Wilcoxon rank-sum tests were performed to examine the relationships between initial EIS dosage and stool microbiome and bacterial functional potential.

RESULTS

There were 105 samples collected before and 237 collected after EIS started from infants with birth gestational age and weight of 28.1 ± 2.4 weeks and 1103 ± 210 g, respectively. The average postnatal age at start of EIS was 17.9 ± 6.9 days and the average initial EIS dose was 4.8 ± 1.1 mg · kg-1 · day-1. Infants who were started on ≥6 mg · kg-1 · day-1 had higher abundances of Proteus and Bifidobacterium and a lower alpha diversity than those started on lower doses (P < 0.05). Infants given higher EIS doses had higher bacterial predicted functional potentials for ferroptosis and epithelial invasion after 2 weeks post EIS.

CONCLUSIONS

Higher EIS dosage is linked to higher abundances of Proteus and Bifidobacterium, and a less diverse microbiome and higher predicted potential of bacterial epithelial invasion. These observational findings should be further studied in a randomized study to elucidate the optimal dosage of EIS in VLBW infants.

Iron Homeostasis Disruption and Oxidative Stress in Preterm Newborns

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

Iron supplementation in preterm and low-birth-weight infants: a systematic review of intervention studies

Context

Enteral iron supplementation in preterm infants is recommended to supply sufficient iron for growth and development without increasing the risk of iron overload. However, the current recommendations date from 2010 and are based on limited evidence.

Objective

This systematic review aimed to investigate the effects of enteral iron supplementation on iron status, growth, neurological development, and adverse clinical outcomes in preterm (<37 weeks’ gestation) and low-birth-weight (LBW, <2500 g) infants.

Data sources

The PubMed/Medline and Cochrane Library databases were searched to 31 October 2018.

Data extraction

Of the 684 records identified, 27 articles, describing 18 randomized controlled trials (RCTs) plus 4 nonrandomized interventions, were included. Using the Cochrane Collaboration’s criteria, study quality was found to be poor to fair overall.

Results

Most articles (23/27) reported iron status indices; supplementation for ≥8 weeks resulted in increased hemoglobin and ferritin concentrations and a reduction in iron deficiency and anemia. No article reported on iron overload. Growth-related parameters reported in 12 articles were not affected by supplementation. Among the 7 articles on neurological development, a positive effect on behavior at 3.5 and 7 years was observed in one Swedish RCT. No association was found between supplementation and adverse clinical outcomes in the 9 articles reporting on studies in which such data was collected.

Conclusions

Long-term iron supplementation appears to result in improved iron status and a reduction in iron deficiency and anemia in preterm and LBW infants. However, high-quality evidence regarding the long-term effects of supplementation on functional health outcomes is lacking. Iron overload has largely been ignored. Well-designed, long-term, dose-response RCTs are required to ascertain the optimal dose and delivery method for the provision of dietary iron in preterm infants, with consideration of short- and long-term health effects.

Systematic Review Registration

PROSPERO registration no. CRD42018085214.

Do effects of early life interventions on linear growth correspond to effects on neurobehavioural development? A systematic review and meta-analysis

BACKGROUND

Faltering in linear growth and neurobehavioural development during early childhood are often assumed to have common causes because of their consistent association. This notion has contributed to a global focus on the promotion of nutrition during pregnancy and childhood to improve both conditions. Our aim was to assess whether effects of interventions on linear growth are associated with effects on developmental scores and to quantify these associations.

METHODS

In this systematic review and meta-analysis, we included randomised trials done during pregnancy and in children aged 0-5 years that reported effects of any intervention on length-for-age or height-for-age Z scores (LAZ or HAZ) and on any of the following outcomes: motor, cognitive or mental, language, and social-emotional or behavioural development. We searched MEDLINE (Ovid), CINAHL (EBSCO), and PsycINFO (EBSCO) from database inception to June 25, 2019. Study-level data were extracted and, when required, authors were contacted for missing information. We calculated weighted meta-regression coefficients of the association between standardised effect sizes of interventions on LAZ or HAZ and developmental outcome scores and calculated pooled effect sizes for different types of intervention.

FINDINGS

Of the 7207 studies identified, we included 75 studies with 122 comparisons between intervention and control groups and outcomes reported for 72 275 children. Across all interventions, effect sizes on LAZ or HAZ were significantly associated with effect sizes on social-emotional scores (β 0·23, 95% CI 0·05 to 0·41; p=0·02), but not on cognitive (0·18, -0·36 to 0·72; p=0·51), language (0·12, -0·07 to 0·31; p=0·21), or motor development scores (0·23, -0·05 to 0·50; p=0·11). In studies that provided nutritional supplements, we observed positive significant pooled effect sizes on all five outcomes of LAZ or HAZ (effect size 0·05, 95% CI 0·01-0·09; p=0·01; n=50), cognitive or mental (0·06, 0·03-0·10; p<0·01; n=38), language (0·08, 0·03-0·13; p=0·01; n=21), motor (0·08, 0·04-0·12; p<0·01; n=41), and social-emotional (0·07, 0·02-0·12; p=0·01; n=20) scores. The effect sizes of nutritional supplementation on LAZ or HAZ scores were significantly associated with effect sizes on cognitive (β 0·40, 95% CI 0·04-0·77; p=0·049) and motor (0·43, 0·11-0·75; p=0·01) scores. In the 14 interventions promoting responsive care and learning opportunities, the pooled effect size on LAZ or HAZ score was not significant (-0·01, 95% CI -0·07 to 0·05; p=0·74), but pooled effect sizes on cognitive, language, and motor scores were 4 to 5 times larger (range 0·38-0·48) than the pooled effect sizes of nutritional supplementation (0·05-0·08).

INTERPRETATION

In nutritional supplementation interventions, improvements in linear growth were associated with small improvements in child development, whereas nurturing and stimulation interventions had significant effects on child development but no effects on linear growth. The determinants of linear growth and neurodevelopment are only partly shared. To nurture thriving individuals and communities, interventions should specifically target determinants of neurodevelopment and not simply linear growth.

FUNDING

University of California Davis, US Department of Agriculture National Institute of Food and Agriculture.

[Research advances in the relationship between iron deficiency and neurodevelopment in preterm infants]

Iron deficiency (ID) is the most common micronutrient deficiency in children. Due to insufficient iron storage at birth and rapid catch-up growth after birth, preterm infants tend to have a high incidence rate of ID. During the critical period of brain development, ID alters iron-dependent neurometabolism, neurochemistry, neuroanatomy, and gene/protein profiles. This affects the central nervous system and causes the change in neurocognitive and behavioral development. Iron supplementation in infancy cannot reverse neurodevelopmental impairment caused by perinatal ID. The influence of ID on neurodevelopment is time- and region-specific, and in the high-risk population, early diagnosis and optimal iron treatment may help with the recovery of brain function and improve quality of life and long-term prognosis in preterm infants.

Development of iron homeostasis in infants and young children

Healthy, term, breastfed infants usually have adequate iron stores that, together with the small amount of iron that is contributed by breast milk, make them iron sufficient until ≥6 mo of age. The appropriate concentration of iron in infant formula to achieve iron sufficiency is more controversial. Infants who are fed formula with varying concentrations of iron generally achieve sufficiency with iron concentrations of 2 mg/L (i.e., with iron status that is similar to that of breastfed infants at 6 mo of age). Regardless of the feeding choice, infants' capacity to regulate iron homeostasis is important but less well understood than the regulation of iron absorption in adults, which is inverse to iron status and strongly upregulated or downregulated. Infants who were given daily iron drops compared with a placebo from 4 to 6 mo of age had similar increases in hemoglobin concentrations. In addition, isotope studies have shown no difference in iron absorption between infants with high or low hemoglobin concentrations at 6 mo of age. Together, these findings suggest a lack of homeostatic regulation of iron homeostasis in young infants. However, at 9 mo of age, homeostatic regulatory capacity has developed although, to our knowledge, its extent is not known. Studies in suckling rat pups showed similar results with no capacity to regulate iron homeostasis at 10 d of age when fully nursing, but such capacity occurred at 20 d of age when pups were partially weaned. The major iron transporters in the small intestine divalent metal-ion transporter 1 (DMT1) and ferroportin were not affected by pup iron status at 10 d of age but were strongly affected by iron status at 20 d of age. Thus, mechanisms that regulate iron homeostasis are developed at the time of weaning. Overall, studies in human infants and experimental animals suggest that iron homeostasis is absent or limited early in infancy largely because of a lack of regulation of the iron transporters DMT1 and ferroportin.

Perspective: What Makes It So Difficult to Mitigate Worldwide Anemia Prevalence?

Anemia can be related to decreased production or increased loss of erythrocytes, or both, leading to many underlying and often overlapping causes. A largely cereal-based diet with plenty of phytates, polyphenols, and other ligands that inhibit intestinal iron absorption predominated in preindustrial Europe and predominates in present-day developing countries alike. In both situations, we find poor hygienic conditions, which frequently lead to anemia of inflammation. The large number of possible causes and their interaction shows why it is so difficult to mitigate anemia prevalence. Diagnostic biomarkers are required to differentiate the different types of anemia and to treat them appropriately. Some of them are well established in adults [e.g., concentrations of serum ferritin, soluble transferrin receptor (sTfR), and serum iron or the ratio of sTfR to log ferritin]. Others, such as serum hepcidin, hold considerable promise, although they are not yet widely used. A particular issue is to establish reference values for biomarkers in infants and children at different ages. The fact that resource-rich postindustrial societies have a very low prevalence of iron-deficiency anemia offers hope that common types of anemia can be eliminated. In contrast, inborn forms of anemia, such as thalassemia, and anemias related to underlying diseases (e.g., bleeding tumors or peptic ulcers, gynecologic blood losses, or renal diseases) require an operational health system to be addressed appropriately.

Early Nutritional Interventions for Brain and Cognitive Development in Preterm Infants: A Review of the Literature

Adequate nutrition is important for neurodevelopmental outcomes in preterm-born infants. In this review, we aim to summarize the current knowledge on nutritional interventions initiated during the hospital stay targeting brain and cognitive development benefits in preterm human infants. Studies can broadly be split in general dietary intervention studies and studies investigating specific nutrients or nutritional supplements. In general, mother's breast milk was reported to be better for preterm infants' neurodevelopment compared to infant formula. The differences in methodologies make it difficult to conclude any effects of interventions with individual nutrients. Only protein and iron level studies showed some consistent findings regarding optimal doses; however, confirmatory studies are needed. This review does not support some widely accepted associations, such as that between long-chain polyunsaturated fatty acid supplementation and visual development. Clear nutritional recommendations cannot be made based on this review. However, the type of infant nutrition (i.e., breast milk versus formula or donor milk), the timing of the nutritional intervention, and the dose of the nutrient/supplement have been found to be relevant factors in determining the success of nutritional intervention studies in preterm infants.

Early and late Iron supplementation for low birth weight infants: a meta-analysis

Background

Iron deficiency in infancy is associated with a range of clinical and developmentally important issues. Currently, it is unclear what is the optimal timing to administer prophylactic enteral iron supplementation in preterm and very low birth weight infants. The objective of this meta-analysis was to evaluate early compared with late iron supplementation in low birth weight infants.

Methods

PubMed and Cochrane Library databases were searched up to May 10, 2014 for studies that compared the benefit of early and late iron supplementation in infants of low birth weight. Sensitivity analysis was carried out using the leave one-out approach and the quality of the included data was assessed.

Results

The data base search and detailed review identified four studies that were included in the meta-analysis. The number of included patients was 246 (n = 121 for early supplementation and n = 125 for late supplementation) and the majority were premature infants. Across studies, early supplementation ranged from as early as enteral feeding was tolerated to 3 weeks, and late supplementation ranged from 4 weeks to about 60 days. Early treatment was associated with significantly smaller decreases in serum ferritin and hemoglobin levels (P < 0.001). In addition, the rate of blood transfusions was lower with early compared with late iron supplementation (P = 0.022). There was no difference between early and late supplementation in the number of patients with nectorizing enteroclitis (>bell stage 2) (P = 0.646). Sensitivity analysis indicated no one study overly influenced the findings and that the data was reliable.

Conclusion

In conclusion, early iron supplementation resulted in less a decrease in serum ferritin and hemoglobin levels in infants with low birth rate. However, caution should be used when treating infants with iron so as not to result in iron overload and possibly negative long-term effects on neurodevelopment.

Early versus late enteral prophylactic iron supplementation in preterm very low birth weight infants: a randomised controlled trial

OBJECTIVES

To evaluate whether preterm very low birth weight (VLBW) infants receiving early iron (EI) supplementation (2 mg/kg/day elemental iron) at 2 weeks postnatal age have improved serum ferritin levels compared with late iron (LI) supplementation at 6 weeks postnatal age.

DESIGN

Single-blinded parallel-group interventional randomised controlled trial.

SETTING

Tertiary care centre in southern India.

INTERVENTIONS

Randomised at 2 weeks postnatal age to EI and LI groups and evaluated at 2, 6 and 12 weeks postnatal age.

OUTCOME

The primary outcome was serum ferritin level at 12 weeks, and the secondary outcomes were the incidence of neonatal morbidities, haemoglobin level, anthropometric parameters and blood transfusion requirements.

RESULTS

Of the 104 babies randomised, outcomes were analysed in 46 and 47 babies in EI and LI groups, respectively. Serum ferritin level was significantly higher (p<0.001) at 12 weeks (82±5 vs 63±3 ng/mL) in the EI group. Haemoglobin (10.1±0.4 vs 9.2±0.4 g/dL) and mean corpuscular haemoglobin concentration (31±0.5 vs 29.4±0.5 g/dL) were also significantly (p<0.001) higher at 12 weeks in the EI group. There was a significant decrease of ferritin in the LI group and significant increase in ferritin in the EI group at 6 weeks compared with 2 weeks. There were no significant differences in the incidences of neonatal morbidities (necrotising enterocolitis, periventricular leukomalacia, retinopathy of prematurity), anthropometric parameters and blood transfusion requirements between the two groups.

CONCLUSIONS

EI supplementation in preterm VLBW infants improves serum ferritin and haemoglobin levels.

TRIAL REGISTRATION

CTRI/2013/01/003277.

Iron requirements of infants and toddlers

Iron deficiency (ID) is the most common micronutrient deficiency worldwide and young children are a special risk group because their rapid growth leads to high iron requirements. Risk factors associated with a higher prevalence of ID anemia (IDA) include low birth weight, high cow's-milk intake, low intake of iron-rich complementary foods, low socioeconomic status, and immigrant status. The aim of this position paper was to review the field and provide recommendations regarding iron requirements in infants and toddlers, including those of moderately or marginally low birth weight. There is no evidence that iron supplementation of pregnant women improves iron status in their offspring in a European setting. Delayed cord clamping reduces the risk of ID. There is insufficient evidence to support general iron supplementation of healthy European infants and toddlers of normal birth weight. Formula-fed infants up to 6 months of age should receive iron-fortified infant formula, with an iron content of 4 to 8 mg/L (0.6-1.2 mg(-1) · kg(-1) · day(-1)). Marginally low-birth-weight infants (2000-2500 g) should receive iron supplements of 1-2 mg(-1) · kg(-1) · day(-1). Follow-on formulas should be iron-fortified; however, there is not enough evidence to determine the optimal iron concentration in follow-on formula. From the age of 6 months, all infants and toddlers should receive iron-rich (complementary) foods, including meat products and/or iron-fortified foods. Unmodified cow's milk should not be fed as the main milk drink to infants before the age of 12 months and intake should be limited to <500 mL/day in toddlers. It is important to ensure that this dietary advice reaches high-risk groups such as socioeconomically disadvantaged families and immigrant families.

Health effects of different dietary iron intakes: a systematic literature review for the 5th Nordic Nutrition Recommendations

BACKGROUND

The present literature review is part of the NNR5 project with the aim of reviewing and updating the scientific basis of the 4th edition of the Nordic Nutrition Recommendations (NNR) issued in 2004.

OBJECTIVE

The objective of this systematic literature review was to assess the health effects of different intakes of iron, at different life stages (infants, children, adolescents, adults, elderly, and during pregnancy and lactation), in order to estimate the requirement for adequate growth, development, and maintenance of health.

METHODS

The initial literature search resulted in 1,076 abstracts. Out of those, 276 papers were identified as potentially relevant. Of those, 49 were considered relevant and were quality assessed (A, B, or C). An additional search on iron and diabetes yielded six articles that were quality assessed. Thus, a total of 55 articles were evaluated. The grade of evidence was classified as convincing (grade 1), probable (grade 2), suggestive (grade 3), and inconclusive (grade 4).

RESULTS

There is suggestive evidence that prevention or treatment of iron deficiency (ID) and iron deficiency anemia (IDA) improves cognitive, motoric, and behavioral development in young children, and that treatment of IDA improves attention and concentration in school children and adult women. There is insufficient evidence to show negative health effects of iron intakes in doses suggested by the NNR 4. There is insufficient evidence to suggest that normal birth weight, healthy, exclusively breast-fed infants need additional dietary iron before 6 months of life in the Nordic countries. An iron concentration of 4-8 mg/L in infant formulas seems to be safe and effective for normal birth weight infants. There is probable evidence that iron supplements (1-2 mg/kg/day) given up to 6 months of age to infants with low birth weight (<2,500 g) prevents IDA and possibly reduce the risk of behavioral problems later on. There is probable evidence that ID and IDA in pregnant women can be effectively prevented by iron supplementation at a dose of 40 mg/day from week 18-20 of gestation. There is probable evidence that a high intake of heme iron, but not total dietary, non-heme or supplemental iron, is associated with increased risk of type 2 diabetes (T2D) and gestational diabetes.

CONCLUSIONS

Overall, the evidence does not support a change of the iron intakes recommended in the NNR 4. However, one could consider adding recommendations for infants below 6 months of age, low birth weight infants and pregnant women.

Selected macro/micronutrient needs of the routine preterm infant

Requirements for optimal nutrition, especially for micronutrients, are not well defined for premature infants. The "reference fetus," developed by Ziegler et al,(1) has served as a model to define nutritional needs and studies designed to determine nutrient requirements. Revision of nutrient requirements and provision of optimal nutrition may lead to improved outcomes in preterm infants. Appropriate provision of nutrients also may help prevent nutritional disorders, such as metabolic bone disease and anemia. In this review, we discuss calcium, phosphorus, magnesium, vitamin D, iron, and copper, and define optimal intakes based on the available published data.

Effect of iron-fortified foods on hematologic and biological outcomes: systematic review of randomized controlled trials

BACKGROUND

The utility of iron fortification of food to improve iron deficiency, anemia, and biological outcomes is not proven unequivocally.

OBJECTIVES

The objectives were to evaluate 1) the effect of iron fortification on hemoglobin and serum ferritin and the prevalence of iron deficiency and anemia, 2) the possible predictors of a positive hemoglobin response, 3) the effect of iron fortification on zinc and iron status, and 4) the effect of iron-fortified foods on mental and motor development, anthropometric measures, and infections.

DESIGN

Randomized and pseudorandomized controlled trials that included food fortification or biofortification with iron were included.

RESULTS

Data from 60 trials showed that iron fortification of foods resulted in a significant increase in hemoglobin (0.42 g/dL; 95% CI: 0.28, 0.56; P < 0.001) and serum ferritin (1.36 μg/L; 95% CI: 1.23, 1.52; P < 0.001), a reduced risk of anemia (RR: 0.59; 95% CI: 0.48, 0.71; P < 0.001) and iron deficiency (RR: 0.48; 95% CI: 0.38, 0.62; P < 0.001), improvement in other indicators of iron nutriture, and no effect on serum zinc concentrations, infections, physical growth, and mental and motor development. Significant heterogeneity was observed for most of the evaluated outcomes. Sensitivity analyses and meta-regression for hemoglobin suggested a higher response with lower trial quality (suboptimal allocation concealment and blinding), use of condiments, and sodium iron edetate and a lower response when adults were included.

CONCLUSION

Consumption of iron-fortified foods results in an improvement in hemoglobin, serum ferritin, and iron nutriture and a reduced risk of remaining anemic and iron deficient.

Benefits of iron supplementation for low birth weight infants: a systematic review

Background

A number of studies have reported on the effects of iron supplementation in low birth weight infants; however, no systematic review of the available evidence has been conducted to date. Hence, we performed a systematic review of the literature to examine the effects of iron supplementation on hematologic iron status, growth, neurodevelopment, and adverse effects in low birth weight/premature infants.

Methods

We searched the Cochrane Library, Medline, and PubMed for articles reporting on the effects of iron supplementation in low weight infants. The following search terms were used: “preterm born infant(s)/children”; “preterm infants”; “prematurely born children” “weight less than 1500 g at birth”; “born prematurely”; “low birth weight infant(s)”; “infants born preterm”; “prematurity”; “small-for-gestational age”; “very small gestational age infants”; “iron supplementation”; “iron intake”; “iron supplements”; “ferric and/or ferrous compounds”; and “ferrous sulphate/fumarate/sulfate”.

Results

A total of 15 studies were identified and included in the systematic review. Supplemental iron was given orally or as an iron-fortified formula in 14/15 studies. The duration of treatment ranged from 1 week to 18 months. Iron supplementation significantly increased hematologic measures of iron status (including hemoglobin, hematocrit, serum ferritin) relative to placebo or over time in most studies. All controlled studies that examined iron-deficiency anemia (IDA)/ID reported a decreased prevalence of IDA/ID with iron supplementation. Dose dependent decreases in the prevalence of IDA/ID were reported in several studies. Of the 5 studies reporting on growth, none found any significant effect on growth-related parameters (length, height, weight, and head circumference). Only 2 studies reported on neurodevelopment; no marked effects were reported. There were no consistently reported adverse effects, including oxidative stress, inhibited nutrient absorption, morbidity, or the requirement for blood transfusion.

Conclusion

The available data suggest that iron supplementation increases the levels of hematologic indicators of iron status and reduces the prevalence of IDA/ID in low birth weight/premature infants. There is insufficient evidence to make a definitive statement regarding the effects of iron supplementation on growth, neurodevelopment, or the occurrence of adverse effects in low birth weight/premature infants.

Enteral iron supplementation in preterm and low birth weight infants

BACKGROUND

Preterm infants are at risk of exhausting their body iron stores much earlier than healthy term newborns. It is widespread practice to give enteral iron supplementation to preterm and low birth weight infants to prevent iron deficiency anaemia. However, it is unclear whether supplementing preterm and low birth weight infants with iron improves growth and neurodevelopment. It is suspected that excess exogenous iron can contribute to oxidative injury in preterm babies, causing or exacerbating conditions such as necrotising enterocolitis and retinopathy of prematurity. Additionally, the optimal dose and timing of commencement and cessation of iron supplementation are uncertain.

OBJECTIVES

To evaluate the effect of prophylactic enteral iron supplementation on growth and neurodevelopmental outcomes in preterm and low birth weight infants. The secondary objectives were to determine whether iron supplementation results in improved haematological parameters and prevents other causes of morbidity and mortality.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. We searched Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 8), MEDLINE (1951 to August 2011), CINAHL (1982 to August 2011) and conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-randomised trials that compared enteral iron supplementation with no iron supplementation, or different regimens of enteral iron supplementation in preterm or low birth weight infants or both.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group. Both review authors separately evaluated trial quality and data extraction. We synthesised data using risk ratios (RRs), risk differences (RDs) and weighted mean differences (WMDs). Where data about the methodology and results or both were lacking, we made an attempt to contact the study authors for further information.

MAIN RESULTS

We included twenty-six studies (2726 infants) in the analysis. The heterogeneity of participants, methods and results precluded an extensive quantitative synthesis. Of the 21 studies comparing iron supplementation with controls, none evaluated neurodevelopmental status as an outcome. Of thirteen studies reporting at least one growth parameter as an outcome, only one study of poor quality found a significant benefit of iron supplementation. Regarding haematological outcomes, no benefit for iron supplementation was demonstrated within the first 8.5 weeks of postnatal life (16 trials), except by two poor quality studies. After this age, most studies reported a higher mean haemoglobin in iron-supplemented infants. We were only able to include a limited number of studies in a quantitative meta-analysis, which suggested the haemoglobin concentration in iron-supplemented infants was higher by about 6 g/L at six to nine months. One study comparing high dose and low dose iron supplementation monitored neurodevelopmental outcome for one year, without finding any significant difference between the groups. One study comparing early versus late commencement of iron supplementation found no difference in cognitive outcome, but an increased rate of abnormal neurological examination in the late iron group at five years of age. The studies comparing high and low doses of iron indicated that there was no discernible haematological benefit in exceeding 'standard' doses of iron (i.e. 2 mg/kg/day to 3 mg/kg/day).

AUTHORS' CONCLUSIONS

The available data suggest that infants who receive iron supplementation have a slightly higher haemoglobin level, improved iron stores and a lower risk of developing iron deficiency anaemia when compared with those who are unsupplemented. However, it is unclear whether iron supplementation in preterm and low birth weight infants has long term benefits in terms of neurodevelopmental outcome and growth. The optimum timing and duration of iron supplementation remains unclear.

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.

Enteral nutrient supply for preterm infants: commentary from the European Society of Paediatric Gastroenterology, Hepatology and Nutrition Committee on Nutrition

The number of surviving children born prematurely has increased substantially during the last 2 decades. The major goal of enteral nutrient supply to these infants is to achieve growth similar to foetal growth coupled with satisfactory functional development. The accumulation of knowledge since the previous guideline on nutrition of preterm infants from the Committee on Nutrition of the European Society of Paediatric Gastroenterology and Nutrition in 1987 has made a new guideline necessary. Thus, an ad hoc expert panel was convened by the Committee on Nutrition of the European Society of Paediatric Gastroenterology, Hepatology, and Nutrition in 2007 to make appropriate recommendations. The present guideline, of which the major recommendations are summarised here (for the full report, see http://links.lww.com/A1480), is consistent with, but not identical to, recent guidelines from the Life Sciences Research Office of the American Society for Nutritional Sciences published in 2002 and recommendations from the handbook Nutrition of the Preterm Infant. Scientific Basis and Practical Guidelines, 2nd ed, edited by Tsang et al, and published in 2005. The preferred food for premature infants is fortified human milk from the infant's own mother, or, alternatively, formula designed for premature infants. This guideline aims to provide proposed advisable ranges for nutrient intakes for stable-growing preterm infants up to a weight of approximately 1800 g, because most data are available for these infants. These recommendations are based on a considered review of available scientific reports on the subject, and on expert consensus for which the available scientific data are considered inadequate.

Policy statement on iron deficiency in pre-school-aged children

AIM

We aimed to develop policy in relation to three areas: (i) the diagnosis of iron deficiency; (ii) maternal-infant issues and the prevention of iron deficiency; and (iii) the treatment of iron deficiency.

METHODS

Within each of these topic areas we completed a literature review and developed recommendations to help direct activities of the Royal Australasian College of Physicians, update paediatricians and guide clinical practice.

RESULTS

Iron deficiency can be defined using cut-off values for laboratory measures of iron status or, if an intercurrent infection is not present, by demonstrating a response to a therapeutic trial of iron. The appropriate measures of iron status vary depending upon the presence of intercurrent infection. Full-term babies are born with iron stores sufficient to meet their needs to age 4-6 months but premature infants are not. After age 6 months infants are dependent upon dietary iron from complementary foods even with continued breastfeeding. Infants <33 weeks gestation or <1800 g birthweight should receive iron from 4 weeks of age. In most settings recommended treatment of iron deficiency is with oral ferrous sulphate as a single or twice daily dose of between 3 and 6 mg/kg/day.

CONCLUSIONS

Iron deficiency is prevalent and an important determinant of child health. Precise and accurate diagnosis remains challenging. Iron supplementation is required for premature and low-birthweight infants. Oral iron salts remain the recommended treatment of choice in most instances.

Once-weekly and 5-days a week iron supplementation differentially affect cognitive function but not school performance in Thai children

Many studies have reported comparable hemoglobin response in subjects given intermittent and daily iron supplements. However, the effect of intermittent iron supplementation on impaired cognitive function, one of the serious consequences of iron deficiency among children, has not been studied. We investigated the effects of 1 d/wk (weekly) and 5 d/wk (daily) iron supplementation on changes in results of intelligence quotient (IQ), Thai language, and mathematics tests among Thai primary schoolchildren. A double-blind, randomized, placebo-controlled trial was conducted. Primary schoolchildren (n = 397) were randomly assigned to receive iron supplements daily or weekly or placebo. Ferrous sulfate (300 mg) or placebo tablets were given under direct observation by the researcher for 16 wk. Changes in IQ, and Thai language and mathematics scores were then compared. The increases in hemoglobin concentration were comparable in the weekly and daily iron supplementation groups but serum ferritin increased more in the children supplemented daily. Children receiving daily iron supplements, however, had a significantly lower increase in IQ (3 +/- 12 points) than those receiving the supplement weekly (6 +/- 12 points) or placebo (6 +/- 12 points), whereas the last-mentioned two groups did not differ. Z-scores of Thai language and mathematics test results did not differ among the groups. We conclude that weekly iron supplementation is the regimen of choice in this study community.

A double-masked, randomized control trial of iron supplementation in early infancy in healthy term breast-fed infants

OBJECTIVES

To test whether iron supplementation affects hematologic, biochemical, and developmental status in term breast-fed infants.

STUDY DESIGN

Term breast-fed infants (n=77) were randomly selected to receive either 7.5 mg per day of elemental iron as ferrous sulfate or placebo from 1 to 6 months of age. Investigators and families were unaware of group assignment. Complete blood count and ferritin, red cell superoxide dismutase, catalase, plasma ferric reducing antioxidant power, and zinc and copper levels were analyzed at 1, 3.5, 6, and 12 months of age. Bayley mental and psychomotor developmental indexes (MDI and PDI) and visual acuity (with the use of Teller acuity cards) were assessed from 12 to 18 months of age. Analysis performed by analysis of variance and t tests was by intention to treat.

RESULTS

Iron supplementation resulted in higher hemoglobin and mean corpuscular volume at 6 months of age and significantly higher visual acuity and PDI at 13 months of age (100+/-12 vs 93+/-9 [+/-SD]). Treatment and placebo groups did not differ in anthropometric indexes, compliance, biochemical status, or demographic characteristics.

CONCLUSIONS

Iron supplementation of breast-fed infants appears safe and might have beneficial hematologic and developmental effects for some infants.

Essential metals--case study on iron

Iron is a vital element in life. Because of the insolubility of iron oxides and sulfides the implication is that dissolved iron was fairly abundant and that oxygen and sulfide were rare in the atmosphere and ocean. Iron and its compounds present as pollutants in the atmosphere can cause deleterious effects to humans, animals, and materials. Analyses of urban air samples show that the iron content averages 1.6 microg/m(3), with the iron and steel industry probably the most likely source of emission. Iron is a natural component of soils and its concentration can be influenced by some industries. Iron concentration in surface water varies greatly, from 61 ppm to 2680 ppm. The disposition of iron in the human body is regulated by a complex mechanism to maintain homeostasis. Iron concentrations in body tissues must be tightly regulated because excessive iron leads to tissue damage, as a result of formation of free radicals. Iron has the capacity to accept and donate electrons readily. The content of body iron is regulated primarily by absorption since humans have no physiological mechanism by which excess iron is excreted. Iron has been identified as a component of asbestos and other mineral and synthetic fibers. Inhalation of iron oxide fumes or dust by workers in the metal industries may result in deposition of iron particles in lungs, producing an X-ray appearance resembling silicosis. During the last decades efforts regarding dietary iron supply focused mostly on the prevention of deficiencies, especially during growth and pregnancy. The chemical form of the iron influences absorption, as do interrelationships with other dietary components.