Clinical safety of iron-fortified formulas

Effect of Fortified Formula on Growth and Nutritional Status in Young Children: A Systematic Review and Meta-Analysis

Previous reviews of the effect of young child formulas on health outcomes in infants and toddlers have been inconclusive. In this study, we undertook a contemporary synthesis of studies investigating the effects of consuming fortified milk beverages (compared to cow’s milk or unfortified comparator formula) on growth and/or nutritional status in children 1−3 years of age. Five electronic databases were searched (PubMed, Web of Science, Scopus, ProQuest, and Cochrane Library) for randomised controlled trials comparing fortified milk against control milk in young children (9−48 months), published between January 1990 and June 2022. Outcomes were growth, body composition, biochemical markers, and/or nutritional status. Mean differences (MD) were pooled using random-effects meta-analysis where there were ≥3 studies. The risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool. Nineteen articles (12 studies; n = 4795) met the inclusion criteria. Heterogeneity was substantial, likely attributable to considerable variation in study characteristics. Fortified milk was associated with increased weight gain (MD = 0.14 kg [95% CI 0.06, 021], p = 0.0003) compared with control milk. Subgroup analyses demonstrated increases in weight in lower-income countries, and in studies with intervention periods > 6 months. There were no effects of fortified milks on other anthropometric measures. Haemoglobin (MD = 3.76 g/L [95% CI 0.17, 7.34], p = 0.04) and ferritin (MD = 0.01 nmol/L [95% CI 0.00, 0.02], p = 0.02) concentrations were increased in infants consuming fortified milks. Fortified milk beverages appear to offer a safe and acceptable source of complementary nutrition as a short-term strategy for addressing nutritional deficits and may modestly promote weight gain in vulnerable populations when provided for periods > 6 months. This study was prospectively registered with PROSPERO (CRD42022339920) and funded by the Infant Nutrition Council.

Serum Ferritin Threshold for Iron Deficiency Screening in One-Year-Old Children

The American Academy of Pediatrics recommends universal hemoglobin screening for iron deficiency anemia using hemoglobin <110 g/L at the 1-year-old well child visit. Our retrospective study suggests the need for combined hemoglobin and serum ferritin iron deficiency screening and raising the diagnostic serum ferritin threshold to 24-25 μg/L.

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.

Common parenting misconceptions regarding infant care: setting the record straight for parents (and some pediatricians)

PURPOSE OF REVIEW

First-time parents often turn to friends and family for advice regarding feeding, sleeping, bathing, diapering and toilet training, and childhood illnesses. Unfortunately, parents may at times be given incorrect and potentially dangerous advice as several widely embraced parenting practices are no longer deemed appropriate. In addition, young children are cared for by family and friends - many of whom are older and may still subscribe to outdated parenting practices.Parents and grandparents are not the only ones who subscribe to child care myths and misconceptions. Pediatricians also believe in the effectiveness of some outdated child care practices. Although some of these parenting myths are relatively benign, others may indeed pose a significant health risk or safety hazard to a young child. The purpose of this article is to review 10 commonly held myths or misconceptions regarding infant care.

RECENT FINDINGS

In this review article, we not only highlight many of the studies that document which outdated health beliefs are still endorsed by parents and/or pediatricians, but also review the specific health risks associated with these parenting myths or misconceptions.

SUMMARY

It is important that pediatricians educate parents and other primary caregivers about the potential risks of following outdated parenting practices.

In vitro assessment of iron availability from commercial Young Child Formulae supplemented with prebiotics

PURPOSE

Iron is essential for development and growth in young children; unfortunately, iron deficiency (ID) is a significant public health problem in this population. Young Child Formulae (YCF), milk-derived products fortified with iron and ascorbic acid (AA, an enhancer of iron absorption) may be good sources of iron to help prevent ID. Furthermore, some YCF are supplemented with prebiotics, non-digestible carbohydrates suggested to enhance iron bioavailability. The aim of our study was to evaluate iron bioavailability of YCF relative to prebiotic and AA concentrations. We hypothesised that YCF with the highest levels of prebiotics and AA would have the most bioavailable iron.

METHODS

We used the in vitro digestion/Caco-2 cell model to measure iron bioavailability from 4 commercially available YCF with approximately equal amounts of iron, but varying amounts of: AA and the prebiotics fructo- and galacto-oligosaccharides. Caco-2 cell ferritin formation was used as a surrogate marker for iron bioavailability.

RESULTS

The YCF with the highest concentration of prebiotics and AA had the highest iron bioavailability; conversely, the YCF with the lowest concentration of prebiotics and AA had the lowest. After the addition of exogenous prebiotics, so that all tested YCF had equivalent amounts, there was no longer a significant difference between YCF iron bioavailability.

CONCLUSION

Our results suggest that ascorbic acid and prebiotics in YCF improve iron bioavailability. Ensuring that iron is delivered in a bioavailable form would improve the nutritional benefits of YCF in relation to ID/IDA amongst young children; therefore, further exploration of our findings in vivo is warranted.

Iron Supplementation during Pregnancy and Infancy: Uncertainties and Implications for Research and Policy

Iron is particularly important in pregnancy and infancy to meet the high demands for hematopoiesis, growth and development. Much attention has been given to conditions of iron deficiency (ID) and iron deficient anemia (IDA) because of the high global prevalence estimated in these vulnerable life stages. Emerging and preliminary evidence demonstrates, however, a U-shaped risk at both low and high iron status for birth and infant adverse health outcomes including growth, preterm birth, gestational diabetes, gastrointestinal health, and neurodegenerative diseases during aging. Such evidence raises questions about the effects of high iron intakes through supplementation or food fortification during pregnancy and infancy in iron-replete individuals. This review examines the emerging as well as the current understanding of iron needs and homeostasis during pregnancy and infancy, uncertainties in ascertaining iron status in these populations, and issues surrounding U-shaped risk curves in iron-replete pregnant women and infants. Implications for research and policy are discussed relative to screening and supplementation in these vulnerable populations, especially in developed countries in which the majority of these populations are likely iron-replete.

A micronutrient-fortified young-child formula improves the iron and vitamin D status of healthy young European children: a randomized, double-blind controlled trial

BACKGROUND

Iron deficiency (ID) and vitamin D deficiency (VDD) are common among young European children because of low dietary intakes and low compliance to vitamin D supplementation policies. Milk is a common drink for young European children. Studies evaluating the effect of milk fortification on iron and vitamin D status in these children are scarce.

OBJECTIVE

We aimed to investigate the effect of a micronutrient-fortified young-child formula (YCF) on the iron and vitamin D status of young European children.

DESIGN

In this randomized, double-blind controlled trial, healthy German, Dutch, and English children aged 1-3 y were allocated to receive either YCF (1.2 mg Fe/100 mL; 1.7 μg vitamin D/100 mL) or nonfortified cow milk (CM) (0.02 mg Fe/100 mL; no vitamin D) for 20 wk. Blood samples were taken before and after the intervention. The primary and secondary outcomes were change from baseline in serum ferritin (SF) and 25-hydroxyvitamin D [25(OH)D], respectively. ID was defined as SF <12 μg/L in the absence of infection (high-sensitivity C-reactive protein <10 mg/L) and VDD as 25(OH)D <50 nmol/L. Statistical adjustments were made in intention-to-treat analyses for sex, country, age, baseline micronutrient status, and micronutrient intake from food and supplements (and sun exposure in the case of vitamin D outcomes).

RESULTS

The study sample consisted of 318 predominantly Caucasian (∼95%) children. The difference in the SF and 25(OH)D change between the treatment groups was 6.6 μg/L (95% CI: 1.4, 11.7 μg/L; P = 0.013) and 16.4 nmol/L (95% CI: 9.5, 21.4 nmol/L; P < 0.001), respectively. The probability of ID (OR 0.42; 95% CI:0.18, 0.95; P = 0.036) and VDD (OR 0.22; 95% CI: 0.01, 0.51; P < 0.001) after the intervention was lower in the YCF group than in the CM group.

CONCLUSION

Micronutrient-fortified YCF use for 20 wk preserves iron status and improves vitamin D status in healthy young children in Western Europe. This trial was registered at www.trialregister.nl as NTR3609.

Effect of fortified milk on growth and nutritional status in young children: a systematic review and meta-analysis

Objective

Adequate nutrition is critical for optimal growth and development. However, young children may be at risk of nutrient deficiencies when transitioning to weaning foods for a variety of reasons. Supplementation with fortified milk may provide potentially lacking essential nutrients, but effects on growth and nutritional status are yet to be established.

Design

Five databases were searched for randomised controlled trials using fortified milk against control milk in young children. Outcomes were growth, body composition and/or biochemical markers. Pooled differences in means were calculated for continuous outcomes and odds ratios for binary outcomes.

Setting

Randomised controlled trials set in any country.

Subjects

Otherwise healthy children aged 6–47 months.

Results

Fifteen articles met the eligibility criteria. Fortification varied from Fe, Zn, vitamins, essential fatty acids, to pre- and/or probiotics. Frequently reported outcomes were weight, height and Fe status. Studies varied in geographical location, sample size and duration. Fortified milk had minimal effects on weight gain (mean difference=0·17 kg; 95 % CI 0·02, 0·31 kg) compared with control milk. The risk of anaemia was reduced in fortified milk groups (OR=0·32; 95 % CI 0·15, 0·66) compared with control groups. There were no significant effects on height gain, changes in body composition or Hb concentration.

Conclusions

Fortified milk is an effective source of complementary nutrition to supplement children in need when consumed in appropriate amounts in addition to a normal diet. Due to compositional differences, further research on fortified milk is warranted before making global recommendations on benefits for growth and nutritional outcomes in young children.

Iron Fortification: Its Efficacy and Safety in Relation to Infections

Iron-fortification programs are efficacious and effective provided recent guidelines are followed: the iron compound is carefully chosen and its level in the food is based on target population requirements, the amount lacking in the diet, and the iron bioavailability of the diet and the compound. For monitoring, serum ferritin and transferrin receptor should be included in addition to hemoglobin. Thus, recent studies of provision of iron-fortified salt to children in Morocco, rice to children in India, wheat flour to women in Thailand, and fish sauce in Vietnam have demonstrated efficacy and effectiveness. All were in nonmalarious areas, and intestinal parasites were uncommon except in India, where the children were dewormed. C-reactive protein was used to eliminate high ferritin values due to infection. An efficacy study of iron-fortified salt in dewormed school-aged children in Côte d'Ivoire, where the prevalence of malaria parasitemia was 55%, found no change in hemoglobin after 6 months, but serum ferritin increased and transferrin receptor decreased significantly, and the increase in body iron and estimated iron absorbed compared favorably with the results of a study of similar design in Morocco, where the prevalence of iron-deficiency anemia decreased from 30% to 5% after 10 months. Hence, iron-fortification programs in malarious areas may not decrease anemia prevalence but will improve iron status and, presumably, iron-dependent health outcomes. Eight studies in nonmalarious areas, all but one in infants receiving iron-fortified formula, have found no evidence of increase in infections and some evidence of a decrease in respiratory infection. There have been no studies in malarious areas.

Iron Fortification of Foods for Infants and Children in Low-Income Countries: Effects on the Gut Microbiome, Gut Inflammation, and Diarrhea

Iron deficiency anemia (IDA) is common among infants and children in Sub-Saharan Africa and is a leading contributor to the global burden of disease, as well as a hindrance to national development. In-home iron fortification of complementary foods using micronutrient powders (MNPs) effectively reduces the risk for IDA by ensuring that the iron needs of infants and young children are met without changing their traditional diet. However, the iron dose delivered by MNPs is high, and comparable on a mg iron per kg body weight to the supplemental doses (2 mg/kg) typically given to older children, which increases diarrhea risk. In controlled studies, iron-containing MNPs modestly increase risk for diarrhea in infants; in some cases, the diarrhea is severe and may require hospitalization. Recent in vitro and in vivo studies provide insights into the mechanism of this effect. Provision of iron fortificants to school-age children and iron-containing MNPs to weaning infants decreases the number of beneficial ‘barrier’ commensal gut bacteria (e.g., bifidobacteria), increases the enterobacteria to bifidobacteria ratio and abundances of opportunistic pathogens (e.g., pathogenic Escherichia coli), and induces gut inflammation. Thus, although iron-containing MNPs are highly effective in reducing IDA, they may increase gastrointestinal morbidity in infants, and safer formulations are needed.

Iron fortification adversely affects the gut microbiome, increases pathogen abundance and induces intestinal inflammation in Kenyan infants

BACKGROUND

In-home iron fortification for infants in developing countries is recommended for control of anaemia, but low absorption typically results in >80% of the iron passing into the colon. Iron is essential for growth and virulence of many pathogenic enterobacteria. We determined the effect of high and low dose in-home iron fortification on the infant gut microbiome and intestinal inflammation.

METHODS

We performed two double-blind randomised controlled trials in 6-month-old Kenyan infants (n=115) consuming home-fortified maize porridge daily for 4 months. In the first, infants received a micronutrient powder (MNP) containing 2.5 mg iron as NaFeEDTA or the MNP without iron. In the second, they received a different MNP containing 12.5 mg iron as ferrous fumarate or the MNP without the iron. The primary outcome was gut microbiome composition analysed by 16S pyrosequencing and targeted real-time PCR (qPCR). Secondary outcomes included faecal calprotectin (marker of intestinal inflammation) and incidence of diarrhoea. We analysed the trials separately and combined.

RESULTS

At baseline, 63% of the total microbial 16S rRNA could be assigned to Bifidobacteriaceae but there were high prevalences of pathogens, including Salmonella Clostridium difficile, Clostridium perfringens, and pathogenic Escherichia coli. Using pyrosequencing, +FeMNPs increased enterobacteria, particularly Escherichia/Shigella (p=0.048), the enterobacteria/bifidobacteria ratio (p=0.020), and Clostridium (p=0.030). Most of these effects were confirmed using qPCR; for example, +FeMNPs increased pathogenic E. coli strains (p=0.029). +FeMNPs also increased faecal calprotectin (p=0.002). During the trial, 27.3% of infants in +12.5 mgFeMNP required treatment for diarrhoea versus 8.3% in -12.5 mgFeMNP (p=0.092). There were no study-related serious adverse events in either group.

CONCLUSIONS

In this setting, provision of iron-containing MNPs to weaning infants adversely affects the gut microbiome, increasing pathogen abundance and causing intestinal inflammation.

TRIAL REGISTRATION NUMBER

NCT01111864.

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.

Micronutrient fortification of food and its impact on woman and child health: a systematic review

BACKGROUND

Vitamins and minerals are essential for growth and metabolism. The World Health Organization estimates that more than 2 billion people are deficient in key vitamins and minerals. Groups most vulnerable to these micronutrient deficiencies are pregnant and lactating women and young children, given their increased demands. Food fortification is one of the strategies that has been used safely and effectively to prevent vitamin and mineral deficiencies.

METHODS

A comprehensive search was done to identify all available evidence for the impact of fortification interventions. Studies were included if food was fortified with a single, dual or multiple micronutrients and impact of fortification was analyzed on the health outcomes and relevant biochemical indicators of women and children. We performed a meta-analysis of outcomes using Review Manager Software version 5.1.

RESULTS

Our systematic review identified 201 studies that we reviewed for outcomes of relevance. Fortification for children showed significant impacts on increasing serum micronutrient concentrations. Hematologic markers also improved, including hemoglobin concentrations, which showed a significant rise when food was fortified with vitamin A, iron and multiple micronutrients. Fortification with zinc had no significant adverse impact on hemoglobin levels. Multiple micronutrient fortification showed non-significant impacts on height for age, weight for age and weight for height Z-scores, although they showed positive trends. The results for fortification in women showed that calcium and vitamin D fortification had significant impacts in the post-menopausal age group. Iron fortification led to a significant increase in serum ferritin and hemoglobin levels in women of reproductive age and pregnant women. Folate fortification significantly reduced the incidence of congenital abnormalities like neural tube defects without increasing the incidence of twinning. The number of studies pooled for zinc and multiple micronutrients for women were few, though the evidence suggested benefit. There was a dearth of evidence for the impact of fortification strategies on morbidity and mortality outcomes in women and children.

CONCLUSION

Fortification is potentially an effective strategy but evidence from the developing world is scarce. Programs need to assess the direct impact of fortification on morbidity and mortality.

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.

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.

Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age)

This clinical report covers diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants (both breastfed and formula fed) and toddlers from birth through 3 years of age. Results of recent basic research support the concerns that iron-deficiency anemia and iron deficiency without anemia during infancy and childhood can have long-lasting detrimental effects on neurodevelopment. Therefore, pediatricians and other health care providers should strive to eliminate iron deficiency and iron-deficiency anemia. Appropriate iron intakes for infants and toddlers as well as methods for screening for iron deficiency and iron-deficiency anemia are presented.

Food-based strategies improve iron status in toddlers: a randomized controlled trial12

BACKGROUND

Nonanemic iron deficiency is common in toddlers in developed countries. Food-based strategies are safe methods to control and prevent mild micronutrient deficiencies.

OBJECTIVE

Our objective was to determine the efficacy of an increased intake of red meat, or the consumption of iron-fortified milk, in improvement of iron status in toddlers at a population level.

DESIGN

In this 20-wk randomized placebo-controlled trial, 225 healthy nonanemic 12-20-mo-old children were assigned to 1 of 3 groups: red meat (toddlers encouraged to consume approximately 2.6 mg iron from red meat dishes daily), fortified milk [toddlers' regular milk replaced with iron-fortified (1.5 mg iron/100 g prepared milk) cow milk], or control [toddlers' regular milk replaced with nonfortified (0.01 mg iron/100 g prepared milk) cow milk]. Blood samples were collected at baseline and at 20 wk for hemoglobin, serum ferritin, serum transferrin receptor, and C-reactive protein. The prevalence of suboptimal iron status (ie, depleted iron stores, iron-deficient erythropoiesis, and iron deficiency anemia) was determined, and body iron was calculated.

RESULTS

No intervention effects were shown on the prevalence of suboptimal iron status. Serum ferritin increased by 44% (95% CI: 14%, 82%; P = 0.002) in the fortified milk group, did not change (+10%) in the red meat group (95% CI: -7%, 30%; P = 0.241), and tended to decrease (-14%) in the control group (95% CI: -27%, 1%; P = 0.063). By 20 wk, in comparison with the control group, serum ferritin and body iron were significantly higher in the fortified milk group (both P < 0.001), and serum ferritin was significantly higher in the red meat group (P = 0.033).

CONCLUSIONS

Consumption of iron-fortified milk can increase iron stores in healthy nonanemic toddlers, whereas increased intakes of red meat can prevent their decline. This trial was registered at actr.org.au as ACTRN12605000487617.

Increased murine neonatal iron intake results in Parkinson-like neurodegeneration with age

Iron elevation is well-documented in the Parkinsonian midbrain but its cause and contribution to subsequent neurodegeneration remain unknown. Mice administered iron at doses equivalent to those found in iron-fortified human infant formula during a developmental period equivalent to the first human year of life display progressive midbrain neurodegeneration and enhanced vulnerability to toxic injury. This may have major implications for the impact of neonatal iron intake as a potential risk factor for later development of Parkinson's disease (PD).

Behavioral consequences of developmental iron deficiency in infant rhesus monkeys

Human studies have shown that iron deficiency and iron deficiency anemia in infants are associated with behavioral impairment, but the periods of brain development most susceptible to iron deficiency have not been established. In the present study, rhesus monkeys were deprived of iron by dietary iron restriction during prenatal (n=14, 10 microg Fe/g diet) or early postnatal (n=12, 1.5 mg Fe/L formula) brain development and compared to controls (n=12, 100 microg Fe/g diet, 12 mg Fe/L formula) in behavioral evaluations conducted during the first four months of life in the nonhuman primate nursery. Iron deficiency anemia was detected in the pregnant dams in the third trimester and compromised iron status was seen in the prenatally iron-deprived infants at birth, but no iron deficiency was seen in either the prenatally or postnatally iron-deprived infants during the period of behavioral evaluation. Neither prenatal nor postnatal iron deprivation led to significant delays in growth, or gross or fine motor development. Prenatally deprived infants demonstrated a 20% reduced spontaneous activity level, lower inhibitory response to novel environments, and more changes from one behavior to another in weekly observation sessions. Postnatally deprived infants demonstrated poorer performance of an object concept task, and greater emotionality relative to controls. This study indicates that different syndromes of behavioral effects are associated with prenatal and postnatal iron deprivation in rhesus monkey infants and that these effects can occur in the absence of concurrent iron deficiency as reflected in hematological measures.

Risk analysis applied to food fortification

OBJECTIVE

To describe how a risk analysis can be applied to food fortification, with emphasis on voluntary fortification and intake levels that might exceed usual dietary levels.

DESIGN

Use of the risk analysis model as a frame to classify nutrients according to the risk of exceeding upper safe intake levels. Furthermore, to apply the model when discussing possible consequences of liberal fortification practices on eating behaviour and disease patterns.

SETTING

The discussion on food fortification presently going on internationally.

RESULTS

Micronutrients can be classified according to their safety margin, i.e. the size of the interval between the recommended intake and the upper safe level of intake. We suggest that nutrients with a small safety margin, i.e. for which the upper safe level is less than five times the recommended intake, be placed in a category A and should be handled with care (retinol, vitamin D, niacin, folate and all minerals). Category B comprises nutrients with an intermediate safety margin (vitamins E, B6, B12 and C), while nutrients that according to present knowledge are harmless even at 100 times the recommendation (vitamin K, thiamin, riboflavin, pantothenic acid and biotin) are categorised as C.

DISCUSSION

The risk analysis model is a useful tool when assessing the risk of both too low and excess intakes of single micronutrients, but can also be applied to analyse the consequences of fortification practices on eating behaviour and disease patterns. Liberal fortification regulations may, for example, distort the conception of what is healthy food, and drive consumption towards a more unhealthy diet, contributing to the plague of overweight and concomitant increased risk of degenerative diseases.

CONCLUSION

The impact of fortification practices on the total eating pattern of a population should become an integrated part of the discussions and regulations connected to the issue.

Effect of iron supplementation on incidence of infectious illness in children: systematic review

OBJECTIVE

To evaluate the effect of iron supplementation on the incidence of infections in children.

DESIGN

Systematic review of randomised controlled trials.

DATA SOURCES

28 randomised controlled trials (six unpublished and 22 published) on 7892 children.

INTERVENTIONS

Oral or parenteral iron supplementation or fortified formula milk or cereals.

OUTCOMES

Incidence of all recorded infectious illnesses, and individual illnesses, including respiratory tract infection, diarrhoea, malaria, other infections, and prevalence of positive smear results for malaria.

RESULTS

The pooled estimate (random effects model) of the incidence rate ratio (iron v placebo) was 1.02 (95% confidence interval 0.96 to 1.08, P=0.54; P<0.0001 for heterogeneity). The incidence rate difference (iron minus placebo) for all recorded illnesses was 0.06 episodes/child year (-0.06 to 0.18, P=0.34; P<0.0001 for heterogeneity). However, there was an increase in the risk of developing diarrhoea (incidence rate ratio 1.11, 1.01 to 1.23, P=0.04), but this would not have an overall important on public health (incidence rate difference 0.05 episodes/child year, -0.03 to 0.13; P=0.21). The occurrence of other illnesses and positive results on malaria smears (adjusted for positive smears at baseline) were not significantly affected by iron administration. On meta-regression, the statistical heterogeneity could not be explained by the variables studied.

CONCLUSION

Iron supplementation has no apparent harmful effect on the overall incidence of infectious illnesses in children, though it slightly increases the risk of developing diarrhoea.

Dietary intakes of 6-24-month-old urban South Island New Zealand children in relation to biochemical iron status

OBJECTIVE

To investigate food sources and intakes of iron, and dietary factors associated with serum ferritin levels in 6-24-month-old children.

DESIGN

A cross-sectional survey employing proportionate cluster sampling was conducted in 1998/1999. Dietary intakes were assessed using a non-consecutive 3-day weighed food record. Serum ferritin and C-reactive protein were analysed from non-fasting venepuncture blood samples and general sociodemographic data were collected.

SETTING

Cities of Christchurch, Dunedin and Invercargill, New Zealand.

SUBJECTS

Randomly selected healthy 6-24-month-old non-breast-feeding children (n = 226).

RESULTS

Total iron intakes (+/- standard deviation (SD)) among non-breast-feeding infants (< 12 months old; n = 42) and toddlers (> or = 12 months old; n = 184) were 8.4 +/- 2.9 mg day(-1) and 5.0 +/- 2.5 mg day(-1), respectively. Fifteen per cent of infants and 66% of toddlers were at risk of inadequate iron intakes. Main sources of dietary iron were infant formula (60%) for infants and cereals (31%) for toddlers. Meat contributed on average 2% and 10% of dietary iron in the infant and toddler diets, respectively. Dietary factors positively associated with serum ferritin were intakes of iron and vitamin C, whereas intakes of calcium and dietary fibre were negatively associated. For each 1% increase in percentage of energy from iron-fortified formula concomitant with a 1% decrease from dairy products, there was a 4.2% increased odds of replete iron stores (ferritin > or = 20 microg l(-1)).

CONCLUSIONS

Toddlers were at higher risk of sub-optimal iron intakes than infants. Results suggest that a diet high in bioavailable iron is important for optimising the iron stores of young children in New Zealand.

Iron and breastfeeding

Given the importance of iron nutrition during the first year of life, there are surprisingly few true, randomized, controlled studies addressing this issue; however, it seems that iron deficiency is unlikely in full-term, breastfed infants during the first 6 months of life because these infants' body iron stores are sufficient to meet requirements. After this time, many infants exhaust their iron stores and become dependent on a secondary dietary iron supply. Although iron deficiency is a significant nutritional problem worldwide, most of the adverse effects of iron deficiency in this age group are hypothetical and rely on extrapolation from animal studies or studies at different ages. This, however, also is true of most of the adverse effects of iron excess in this age group. Given this uncertainty, it seems prudent to use the lowest dose of iron that prevents iron-deficiency anemia. Currently, the best evidence is that this is achieved by prolonged breastfeeding, avoidance of unfortified formulas and cow's milk, and the introduction of iron-fortified and vitamin C-fortified weaning foods at approximately 6 months of age. Despite much research, there are many areas of uncertainty regarding iron supplementation of infants, including that: 1. The optimal age for introducing iron-fortified supplemental foods is poorly defined and should be further evaluated. 2. The natural history of iron deficiency and iron-deficiency anemia during the first year of life is unclear, as are the possible long-term effects of this, especially on developmental outcome. 3. The biologic variability among infants and among their mothers that allows many infants who do not receive iron-fortified foods to prevent iron deficiency while receiving only human milk throughout the first year of life is intriguing and warrants additional study. 4. The iron requirements of small-for-gestational-age, term infants are unknown. Their iron requirements are likely to be higher than those of average term infants, but whether iron supplements are required is unclear. 5. The optimum amount of dietary iron in the weaning diet needs to be further defined. Similarly, the optimal source and amount of iron in infant formulas given to infants who receive a mixture of human milk and formula is unclear.