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

Effectiveness of intermittent iron and high-dose vitamin A supplementation on cognitive development of school children in southern Ethiopia: a randomized placebo-controlled trial

BACKGROUND

Iron is an essential mineral whose deficiency results in cognitive alteration, impaired emotional behaviors, and altered myelination and neurotransmission. In animal models, it has been shown that vitamin A (VA) could affect cognition.

OBJECTIVES

The study aimed to evaluate the effectiveness of intermittent iron and VA supplementation on cognitive development of schoolchildren, and to assess the interaction between these supplementations.

METHODS

Considering a 2 × 2 factorial design, 504 children were randomly assigned to 1 of the 4 arms: placebo VA and placebo iron supplement; high-dose vitamin VA and placebo iron supplement; iron supplement and placebo VA; and iron and high-dose vitamin VA supplements. Cognitive development was assessed using Raven's Coloured Progressive Matrices, digit span, Tower of London, and visual search tasks.

RESULTS

The mean [± standard deviation (SD)] age of the enrolled children was 9.6 (±1.6) y. One-fifth of the children had iron deficiency or anemia, whereas 2.9%, 3.9%, and 12.1% of children had low iron stores, iron deficiency anemia, and VA deficiency, respectively. Intermittent iron supplementation did not result in any significant improvement of children's cognitive development and had a negative effect on the performance index of the visual search task compared with placebo (-0.17 SD, 95% confidence interval: -0.32, -0.02). Effects were evident among children with stunting, thinness, or children coming from understimulating home environments. High-dose VA supplementation resulted in a significant improvement of digit span z-score with a mean difference of 0.30 SD (95% confidence interval: 0.14, 0.46) compared with placebo VA. VA had a more beneficial impact for girls, children infected with helminths, and those from food secure households.

CONCLUSION

In a population where the prevalence of iron deficiency is low, intermittent iron supplementation did not have any or negative effect on the child's cognitive development outcomes. Conversely, VA supplementation improved the child's working memory.

TRIAL REGISTRATION NUMBER

The study is registered at clinicaltrials.gov as NCT04137354 (https://clinicaltrials.gov/study/NCT04137354).

Effects of iron supplementation on cognitive development in school-age children: Systematic review and meta-analysis

BACKGROUND

Iron deficiency is negatively associated with children's cognitive development. Evidence showed that iron supplementation improves cognitive development. Nearly 50% of anemia is caused by iron deficiency. Anemia affects more school-age children, at an age where their brain development continues. The aim of this systematic review and meta-analysis is to review the evidence from published randomized controlled trials to evaluate the effects of iron supplementation on cognitive development and function among school-age children.

METHOD

Five databases including MEDLINE, EMBASE, Scopus, Web of Science and CENTRAL were used to search for articles on April 20th, 2021. The search was reconducted on October 13th, 2022 to retrieve new records. Studies were eligible if they included school children 6-12 years of age, were randomized controlled trials, and if they tested iron supplementation and measured cognitive development.

RESULT

Thirteen articles were included in the systematic review. Overall, iron supplementation significantly improved intelligence (standardized mean difference, 95% confidence interval) (SMD 0.46, 95%CI: 0.19, 0.73, P<0.001), attention and concentration (SMD 0.44, 95%CI: 0.07, 0.81, P = 0.02) and memory (SMD 0.44, 95%CI: 0.21, 0.67, P <0.001) of school-age children. There was no significant effect of iron supplementation on school achievement of school-age children (SMD 0.06, 95%CI: -0.15, 0.26, P = 0.56). In a subgroup analysis, iron-supplemented children who were anemic at baseline had had better outcomes of intelligence (SMD 0.79, 95%CI: 0.41, 1.16, P = 0.001) and memory (SMD 0.47, 95%CI: 0.13, 0.81; P = 0.006).

CONCLUSION

Iron supplementation has a significant positive effect on the intelligence, attention and concentration, and the memory of school-age children but there was no evidence on the effect of iron supplementation on their school achievement.

Effect of Oral Iron Supplementation on Cognitive Function among Children and Adolescents in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

BACKGROUND

There is abundant evidence showing that iron deficiency is closely linked with delayed brain development, worse school performance, and behavioral abnormalities. However, evidence on the impact of iron supplementation among children and adolescents in low- and middle-income countries (LMICs) has been inconsistent. This study aims to examine the effect of oral iron supplementation on cognitive function among children and adolescents in LMICs.

METHODS

A systematic review and meta-analysis was conducted to examine the impact of iron supplementation on cognitive function (including intelligence, attention, short-term memory, long-term memory, and school performance) among children and adolescents aged 5 to 19. We searched PubMed, Embase, Web of Science, CINAHL, and references of related articles published from the inception of the databases to 1 May 2022. Random-effects pooled standardized mean difference (SMD) with 95% confidence intervals (CIs) were calculated to estimate the effect of iron supplementation on cognitive function. We also investigated the heterogeneity of the effects using subgroup and meta-regression analyses. This review was registered with PROSPERO (CRD42020179064).

RESULTS

Nine studies with 1196 individual participants from five countries were identified and included. Iron had a positive impact on intelligence test scores among children and adolescents (SMD = 0.47, 95% confidence interval [CI]: 0.10, 0.83). Meta-regression showed that the intelligence test scores improved with increasing the iron supplement dose (odds ratio [CI] = 1.02, 95% CI: 1.00, 1.04). There were no significant effects on attention, short-term memory, long-term memory, or school performance.

CONCLUSIONS

Oral iron intake can improve the intelligence test scores of children and adolescents in LMICs and should be considered for future nutritional interventions.

Effects of iron intake on neurobehavioural outcomes in African children: a systematic review and meta-analysis of randomised controlled trials

Background: Iron deficiency and developmental delay are common in African children. While experimental studies indicate an important role of iron in brain development, effects of iron on child development remain unclear. We aimed to evaluate the effects of iron supplementation or fortification on neurobehavioural outcomes in African children and further summarise these effects in children living in non-African countries for comparison. Methods: We searched PubMed, EMBASE, PsycINFO, Scopus and Cochrane Library for studies published up to 22 nd October 2021. We included randomised controlled trials (RCTs) evaluating effects of iron supplementation or fortification on neurobehavioural outcomes in children. Due to heterogeneity in study methods, we analysed all studies qualitatively and in secondary analyses only seven RCTs with 11 arms were meta-analysed. Results: We identified 2231 studies and included 35 studies (n=9988) in the systematic review. Only five studies (n=1294) included African children while 30 (n=8694) included children living in non-African countries. Of the five African studies, two (n=647) reported beneficial effects of iron supplementation on neurobehavioural outcomes in anaemic children, while three (n=647) found no beneficial effects. Of 30 studies in children living in non-African countries, 10 (n=3105) reported beneficial effects of iron supplementation or fortification on neurobehavioural outcomes, seven (n=786) reported beneficial effects only in children who had iron deficiency, iron deficiency anaemia or anaemia while 13 (n=4803) reported no beneficial effects. Conclusions: There are few studies in African children despite the high burden of iron deficiency and developmental delay in this population. Evidence on the effects of iron supplementation on neurobehavioural outcomes remains unclear and there is need for further well-powered studies evaluating these effects in African populations. PROSPERO registration: CRD42018091278 (20/03/2018).

Effects of iron intake on neurobehavioural outcomes in African children: a systematic review and meta-analysis of randomised controlled trials

Background: Iron deficiency and developmental delay are common in African children. While experimental studies indicate an important role of iron in brain development, effects of iron on child development remain unclear. We aimed to evaluate the effects of iron supplementation or fortification on neurobehavioural outcomes in African children and further summarise these effects in children living in non-African countries for comparison. Methods: We searched PubMed, EMBASE, PsycINFO, Scopus and Cochrane Library for studies published up to 9 th March 2021. We included randomised controlled trials (RCTs) evaluating effects of iron supplementation or fortification on neurobehavioural outcomes in children. Due to heterogeneity in study methods, we analysed the studies qualitatively and only seven RCTs with 11 arms were meta-analysed. Results: We identified 2155 studies and included 34 studies (n=9808) in the systematic review. Only five studies (n=1294) included African children while 29 (n=8514) included children living in non-African countries. Of the five African studies, two (n=647) reported beneficial effects of iron supplementation on neurobehavioural outcomes in anaemic children while three (n=647) found no beneficial effects. Of 29 studies in children living in non-African countries, nine (n=2925) reported beneficial effects of iron supplementation or fortification on neurobehavioural outcomes, seven (n=786) reported beneficial effects only in children who had iron deficiency, iron deficiency anaemia or anaemia while 13 (n=4803) reported no beneficial effects. Meta-analysis of seven studies (n=775) in non-African countries showed no beneficial effects of iron supplementation on cognitive or motor development in children. Conclusions: There are few studies in African children despite the high burden of iron deficiency and developmental delay in this population. Evidence on the effects of iron supplementation on neurobehavioural outcomes remains unclear and there is need for further well-powered studies evaluating these effects in African populations. PROSPERO registration: CRD42018091278 (20/03/2018).

Does the fortified milk with high iron dose improve the neurodevelopment of healthy infants? Randomized controlled trial

Background

Since iron plays an important role in several physiological processes, its deficiency but also overload may harm the development of children. The aim was to assess the effect of iron–fortified milk on the iron biochemical status and the neurodevelopment of children at 12 months of age.

Methods

Randomized controlled trial conducted in 133 Spanish children, allocated in two groups to receive formula milk fortified with 1.2 or 0.4 mg/100 mL of iron between 6 and 12 months of age. Psychomotor (PDI) and Mental (MDI) Development Index were assessed by the Bayley Scales before and after the intervention. Maternal obstetrical and psychosocial variables were recorded. The biochemical iron status of children was measured and data about breastfeeding, anthropometry and infections during the first year of life were registered.

Results

Children fortified with 1.2 mg/100 mL of iron, compared with 0.4 mg/100 mL, showed higher serum ferritin (21.5 vs 19.1 μg/L) and lower percentage of both iron deficiency (1.1 to 5.9% vs 3.8 to 16.7%, respectively, from 6 to 12 months) and iron deficiency anemia (4.3 to 1.1% vs 0 to 4.2%, respectively, from 6 to 12 months) at the end of the intervention. No significant differences were found on neurodevelopment from 6 to 12 months between children who received high dose of Fe compared with those who received low dose.

Conclusion

Despite differences on the iron status were observed, there were no effects on neurodevelopment of well–nourished children in a developed country after iron supplementation with doses within dietary recommendations. Follow–up studies are needed to test for long–term neurodevelopmental improvement.

Trial registration

Retrospectively registered in ClinicalTrials.gov with the ID: NCT02690675.

Nutrition (Micronutrients) in Child Growth and Development: A Systematic Review on Current Evidence, Recommendations and Opportunities for Further Research

OBJECTIVE

An important aspect of malnutrition is deficiency of different micronutrients during pregnancy or early childhood. We systematically reviewed the role of nutrition in child growth (weight or height gain) and development.

METHODS

A comprehensive literature search was done on PubMed/Cochrane Library browsing through 38,795 abstracts until December 31, 2016 to select systematic reviews/meta-analyses and individual randomized controlled trials (RCTs) of micronutrient supplementation.

RESULTS

Micronutrients studied included iron, iodine, folate, zinc, calcium, magnesium, selenium, vitamin D, vitamin A, vitamin B complex, and multiple micronutrients. We summarize evidence with details and results of RCTs, highlight strengths/weaknesses, and critically interpret findings. Effects of breastfeeding-promotion, food-supplementation (complementary and school feeding), conditional-cash-transfers, and integrated nutrition/psychosocial interventions are discussed.

CONCLUSION

Based on this evidence we make policy and programmatic recommendations for supplementation to mothers and children at high-risk of deficiency.

Combined Iron Deficiency and Low Aerobic Fitness Doubly Burden Academic Performance among Women Attending University

BACKGROUND

Academic success is a key determinant of future prospects for students. Cognitive functioning has been related to nutritional and physical factors. Here, we focus on iron status and aerobic fitness in young-adult female students given the high rate of iron deficiency and declines in fitness reported in this population.

OBJECTIVES

We sought to explore the combined effects of iron status and fitness on academic success and to determine whether these associations are mediated by cognitive performance.

METHODS

Women (n = 105) aged 18-35 y were recruited for this cross-sectional study. Data were obtained for iron biomarkers, peak oxygen uptake (VO_2peak), grade point average (GPA), performance on computerized attention and memory tasks, and motivation and parental occupation. We compared the GPA of groups 1) with low compared with normal iron status, 2) among different fitness levels, and 3) by using a combined iron status and fitness designation. Mediation analysis was applied to determine whether iron status and VO_2peak influence GPA through attentional and mnemonic function.

RESULTS

After controlling for age, parental occupation, and motivation, GPA was higher in women with normal compared with low ferritin (3.66 ± 0.06 compared with 3.39 ± 0.06; P = 0.01). In analyses of combined effects of iron status and fitness, GPA was higher in women with normal ferritin and higher fitness (3.70 ± 0.08) than in those with 1) low ferritin and lower fitness (3.36 ± 0.08; P = 0.02) and 2) low ferritin and higher fitness (3.44 ± 0.09; P = 0.04). Path analysis revealed that working memory mediated the association between VO_2peak and GPA.

CONCLUSIONS

Low iron stores and low aerobic fitness may prevent female college students from achieving their full academic potential. Investigators should explore whether integrated lifestyle interventions targeting nutritional status and fitness can benefit cognitive function, academic success, and postgraduate prospects.

A question mark on iron deficiency in 185 million people of Pakistan: its outcomes and prevention

Micronutrient deficiency especially the iron deficiency is the bane of our lives, affecting all strata of society. Unfortunately, the women during pregnancy, adolescence, and children are under this curse particularly in developing countries like Pakistan. It is one of the biggest reasons of complications during pregnancy and malnourished children under five years of age. Maternal death, still-births, and underweight births are most common consequences of iron deficiency and these outbreaks as iron-deficiency anemia in Pakistan. Disastrous nature of iron deficiency requires an urgent call to eradicate it. Hence, the solution should not be frail comparing with the huge economic loss and other incompatibilities. Flour fortification, supplementation, dietary diversification, and especially maternal education are possible solutions for combating this micronutrient deficiency.

Comparison of intelligence, weight and height in children after general anesthesia with and without perioperative desaturation in non-cardiac surgery: a historical and concurrent follow-up study

Purpose

To determine whether perioperative desaturation (PD) in preschool children undergoing non-cardiac surgery is associated with subsequent impairment of intelligence or subsequent change in age-specific weight and height percentile.

Method

A historical-concurrent follow-up study was conducted in children aged ≤ 60 months who underwent general anesthesia (GA) for non-cardiac surgery between January 2008 and December 2011 at Songklanagarind Hospital. Children who developed PD (PD group) and children who did not develop perioperative respiratory events (no-PRE group) were matched on sex, age, year of having index GA, type of surgery and choice of anesthesia. The children’s age-specific weight and height percentile and intelligence quotient (IQ) scores by Standford Binet-LM or Wechsler Intelligence Scale for Children, 3rd edition 12–60 months after GA were compared using Student’s t- test and Wilcoxon’s rank sum test. Multivariate linear regression models for standardized IQ and multivariate mixed effects linear regression models for the change of age-specific weight and height percentile from the time of index GA to the time of IQ test were performed to identify independent predictors. The coefficients and 95% confidence intervals (CI) were displayed and considered significant if the F test p-values were < 0.05.

Results

Of 103 subjects in each group (PD vs no-PRE), there were no statistically significant differences in IQ (94.7 vs 98.3, p = 0.13), standardized IQ (−0.1 vs 0.1, p = 0.14) or age-specific weight percentile (38th vs 63th, p = 0.06). However, age-specific height percentile in the PD group at the time of IQ test was significantly lower (38th vs 50th, p = 0.02). In the multivariate analysis, PD was not a significant predictor for standardized IQ (coefficient: −0.06, 95% CI: −0.3, 0.19, p = 0.57), change in age-specific weight percentile (coefficient: 4.66, 95% CI: −2.63, 11.95, p = 0.21) or change in age-specific height percentile (coefficient: −1.65, 95% CI: −9.74, 6.44, p = 0.69) from the time of index GA to the time of IQ test after adjusting for family and anesthesia characteristics.

Conclusion

Our study could not demonstrate any serious effect of PD on subsequent intelligence or on the change in age-specific weight and height percentile of children after non-cardiac surgery.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-3-164) contains supplementary material, which is available to authorized users.

Iron deficiency and cognitive functions

Micronutrient deficiencies, especially those related to iodine and iron, are linked to different cognitive impairments, as well as to potential long-term behavioral changes. Among the cognitive impairments caused by iron deficiency, those referring to attention span, intelligence, and sensory perception functions are mainly cited, as well as those associated with emotions and behavior, often directly related to the presence of iron deficiency anemia. In addition, iron deficiency without anemia may cause cognitive disturbances. At present, the prevalence of iron deficiency and iron deficiency anemia is 2%-6% among European children. Given the importance of iron deficiency relative to proper cognitive development and the alterations that can persist through adulthood as a result of this deficiency, the objective of this study was to review the current state of knowledge about this health problem. The relevance of iron deficiency and iron deficiency anemia, the distinction between the cognitive consequences of iron deficiency and those affecting specifically cognitive development, and the debate about the utility of iron supplements are the most relevant and controversial topics. Despite there being methodological differences among studies, there is some evidence that iron supplementation improves cognitive functions. Nevertheless, this must be confirmed by means of adequate follow-up studies among different groups.

Effects of daily iron supplementation in primary-school-aged children: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Anemia is an important public health and clinical problem. Observational studies have linked iron deficiency and anemia in children with many poor outcomes, including impaired cognitive development; however, iron supplementation, a widely used preventive and therapeutic strategy, is associated with adverse effects. Primary-school-aged children are at a critical stage in intellectual development, and optimization of their cognitive performance could have long-lasting individual and population benefits. In this study, we summarize the evidence for the benefits and safety of daily iron supplementation in primary-school-aged children.

METHODS

We searched electronic databases (including MEDLINE and Embase) and other sources (July 2013) for randomized and quasi-randomized controlled trials involving daily iron supplementation in children aged 5-12 years. We combined the data using random effects meta-analysis.

RESULTS

We identified 16 501 studies; of these, we evaluated 76 full-text papers and included 32 studies including 7089 children. Of the included studies, 31 were conducted in low- or middle-income settings. Iron supplementation improved global cognitive scores (standardized mean difference 0.50, 95% confidence interval [CI] 0.11 to 0.90, p = 0.01), intelligence quotient among anemic children (mean difference 4.55, 95% CI 0.16 to 8.94, p = 0.04) and measures of attention and concentration. Iron supplementation also improved age-adjusted height among all children and age-adjusted weight among anemic children. Iron supplementation reduced the risk of anemia by 50% and the risk of iron deficiency by 79%. Adherence in the trial settings was generally high. Safety data were limited.

INTERPRETATION

Our analysis suggests that iron supplementation safely improves hematologic and nonhematologic outcomes among primary-school-aged children in low- or middle-income settings and is well-tolerated.

Intermittent iron supplementation for improving nutrition and development in children under 12 years of age

BACKGROUND

Approximately 600 million children of preschool and school age are anaemic worldwide. It is estimated that half of the cases are due to iron deficiency. Consequences of iron deficiency anaemia during childhood include growth retardation, reduced school achievement, impaired motor and cognitive development, and increased morbidity and mortality. The provision of daily iron supplements is a widely used strategy for improving iron status in children but its effectiveness has been limited due to its side effects, which can include nausea, constipation or staining of the teeth. As a consequence, intermittent iron supplementation (one, two or three times a week on non-consecutive days) has been proposed as an effective and safer alternative to daily supplementation.

OBJECTIVES

To assess the effects of intermittent iron supplementation, alone or in combination with other vitamins and minerals, on nutritional and developmental outcomes in children from birth to 12 years of age compared with a placebo, no intervention or daily supplementation.

SEARCH METHODS

We searched the following databases on 24 May 2011: CENTRAL (2011, Issue 2), MEDLINE (1948 to May week 2, 2011), EMBASE (1980 to 2011 Week 20), CINAHL (1937 to current), POPLINE (all available years) and WHO International Clinical Trials Registry Platform (ICTRP). On 29 June 2011 we searched all available years in the following databases: SCIELO, LILACS, IBECS and IMBIOMED. We also contacted relevant organisations (on 3 July 2011) to identify ongoing and unpublished studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials with either individual or cluster randomisation. Participants were children under the age of 12 years at the time of intervention with no specific health problems. The intervention assessed was intermittent iron supplementation compared with a placebo, no intervention or daily supplementation.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the eligibility of studies against the inclusion criteria, extracted data from included studies and assessed the risk of bias of the included studies.

MAIN RESULTS

We included 33 trials, involving 13,114 children (˜49% females) from 20 countries in Latin America, Africa and Asia. The methodological quality of the trials was mixed.Nineteen trials evaluated intermittent iron supplementation versus no intervention or a placebo and 21 studies evaluated intermittent versus daily iron supplementation. Some of these trials contributed data to both comparisons. Iron alone was provided in most of the trials.Fifteen studies included children younger than 60 months; 11 trials included children 60 months and older, and seven studies included children in both age categories. One trial included exclusively females. Seven trials included only anaemic children; three studies assessed only non-anaemic children, and in the rest the baseline prevalence of anaemia ranged from 15% to 90%.In comparison with receiving no intervention or a placebo, children receiving iron supplements intermittently have a lower risk of anaemia (average risk ratio (RR) 0.51, 95% confidence interval (CI) 0.37 to 0.72, ten studies) and iron deficiency (RR 0.24, 95% CI 0.06 to 0.91, three studies) and have higher haemoglobin (mean difference (MD) 5.20 g/L, 95% CI 2.51 to 7.88, 19 studies) and ferritin concentrations (MD 14.17 µg/L, 95% CI 3.53 to 24.81, five studies).Intermittent supplementation was as effective as daily supplementation in improving haemoglobin (MD -0.60 g/L, 95% CI -1.54 to 0.35, 19 studies) and ferritin concentrations (MD -4.19 µg/L, 95% CI -9.42 to 1.05, 10 studies), but increased the risk of anaemia in comparison with daily iron supplementation (RR 1.23, 95% CI 1.04 to1.47, six studies). Data on adherence were scarce and it tended to be higher among those children receiving intermittent supplementation, although this result was not statistically significant.We did not identify any differential effect of the type of intermittent supplementation regimen (one, two or three times a week), the total weekly dose of elemental iron, the nutrient composition, whether recipients were male or female or the length of the intervention.

AUTHORS' CONCLUSIONS

Intermittent iron supplementation is efficacious to improve haemoglobin concentrations and reduce the risk of having anaemia or iron deficiency in children younger than 12 years of age when compared with a placebo or no intervention, but it is less effective than daily supplementation to prevent or control anaemia. Intermittent supplementation may be a viable public health intervention in settings where daily supplementation has failed or has not been implemented. Information on mortality, morbidity, developmental outcomes and side effects, however, is still lacking.

Weekly iron supplementation for the prevention of anemia in pre-school children: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

This study analyses the impact of weekly iron supplementation with ferrous sulphate heptahydrate (FeSO4) in 5-year-olds compared with placebo, on hemoglobin (Hb) and hematocrit (Ht) values and anemia.

DESIGN

The study concerns a cluster-randomized, placebo-controlled double-blind trial. Intervention participants received 50 mg elemental iron for 14 weeks.

SETTING

The study population comprised pre-school children (n = 135) from one randomly chosen public school in the northeast of Brazil.

SUBJECTS

Participants were 5-year-old students from a public school.

RESULTS

Mean Hb and Ht values increased after iron supplementation, with p < 0.0001. There was no statistically significant increase in the placebo group. After intervention, anemia prevalence reduced only in the intervention group, from 48.0% to 26.0%.

CONCLUSIONS

Weekly iron supplementation was effective in reducing anemia in 5-year-olds.

Once weekly low-dose iron supplementation effectively improved iron status in adolescent girls

Iron supplementation has been suggested as a strategy for prevention and treatment of iron deficiency (ID) and iron deficiency anemia (IDA) in many countries, but non-compliance of daily regimens and common dosage remain as major challenges. The aim of this study was to investigate the effects of low dose once weekly iron supplementation in adolescent girls. The study was designed as a community-based, randomized, supplementation trial. The initial sample consisted of 200 female high school students, aged 14-16 years old, of whom 193 students concluded the study. They were randomly selected and assigned into either iron-supplemented group (ISG) or iron-unsupplemented group (IUG). The ISG received 150 mg ferrous sulfate once weekly for 16 weeks, whereas the IUG received nothing. Weight, height, and hematological parameters were measured and compared between the two groups before and after the intervention. There was no significant difference between the initial measures of the two groups before the intervention. After 16 weeks of intervention, mean of hemoglobin and serum ferritin improved significantly in ISG compared to IUG. At the beginning of the study, percent of anemia, IDA, and ID in ISG were 12.5%, 8.3%, and 30.2%, whereas these figures for IUG in this period of study were 14.4, 10.3, and 38.2, respectively, which were not significantly different between the two groups. However, percentages of the above items at the end of study in ISG were 2.1%, 0%, and 21.9%, respectively. In contrast to IUG, all cases of IDA were abolished in the ISG. Our study showed that once weekly supplementation of 150 mg ferrous sulfate for 16 weeks significantly improved iron status in female adolescents and effectively treated IDA. There is no need for higher dosage of iron for supplementation that may cause adverse effects and bear higher costs.

The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis

BACKGROUND

In observational studies anaemia and iron deficiency are associated with cognitive deficits, suggesting that iron supplementation may improve cognitive function. However, due to the potential for confounding by socio-economic status in observational studies, this needs to be verified in data from randomised controlled trials (RCTs).

AIM

To assess whether iron supplementation improved cognitive domains: concentration, intelligence, memory, psychomotor skills and scholastic achievement.

METHODOLOGY

Searches included MEDLINE, EMBASE, PsychINFO, Cochrane CENTRAL and bibliographies (to November 2008). Inclusion, data extraction and validity assessment were duplicated, and the meta-analysis used the standardised mean difference (SMD). Subgrouping, sensitivity analysis, assessment of publication bias and heterogeneity were employed.

RESULTS

Fourteen RCTs of children aged 6+, adolescents and women were included; no RCTs in men or older people were found. Iron supplementation improved attention and concentration irrespective of baseline iron status (SMD 0.59, 95% CI 0.29 to 0.90) without heterogeneity. In anaemic groups supplementation improved intelligence quotient (IQ) by 2.5 points (95% CI 1.24 to 3.76), but had no effect on non-anaemic participants, or on memory, psychomotor skills or scholastic achievement. However, the funnel plot suggested modest publication bias. The limited number of included studies were generally small, short and methodologically weak.

CONCLUSIONS

There was some evidence that iron supplementation improved attention, concentration and IQ, but this requires confirmation with well-powered, blinded, independently funded RCTs of at least one year's duration in different age groups including children, adolescents, adults and older people, and across all levels of baseline iron status.

The role of iron in neurocognitive development

In this article we present a review of the current literature relating iron and iron deficiency to psychological and neurobiological outcomes in both humans and experimental animals. In particular, we focus on the role of iron during gestation and infancy and the possible impact on neurobehavioral development in the short and long term. In the context of reviewing this literature, the following questions are addressed: (1) What are the neural mechanisms that are directly influenced by iron and iron deficiency? (2) Does iron play a true causal role in determining these outcomes? (3) Is there a sensitive period during which iron deficiency is most harmful?

Diet- and body size-related attitudes and behaviors associated with vitamin supplement use in a representative sample of fourth-grade students in Texas

OBJECTIVE

To examine diet- and body size-related attitudes and behaviors associated with supplement use in a representative sample of fourth-grade students in Texas.

DESIGN

Cross-sectional data from the School Physical Activity and Nutrition study, a probability-based sample of schoolchildren. Children completed a questionnaire that assessed supplement use, food choices, diet-related attitudes, and physical activity; height and weight were measured.

SETTING

School classrooms.

PARTICIPANTS

Representative sample of fourth-grade students in Texas (n = 5967; mean age = 9.7 years standard error of the mean [SEM] = .03 years, 46% Hispanic, 11% African-American).

MAIN OUTCOME MEASURES

Previous day vitamin supplement consumption, diet- and body size-related attitudes, food choices, demographic factors, and physical activity.

ANALYSIS

Multivariable logistic regression models, P < .05.

RESULTS

The prevalence of supplement use was 29%. Supplement intake was associated with physical activity. Girls who used supplements were more likely to report positive body image and greater interest in trying new food. Relative to nonusers, supplement users were less likely to perceive that they always ate healthful food, although supplement use was associated with more healthful food choices in boys and girls (P < .001).

CONCLUSIONS AND IMPLICATIONS

The widespread use of supplements and clustering of supplement use with healthful diet and greater physical activity in fourth graders suggest that supplement use be closely investigated in studies of diet-disease precursor relations and lifestyle factors in children.

A micronutrient-fortified seasoning powder reduces morbidity and improves short-term cognitive function, but has no effect on anthropometric measures in primary school children in northeast Thailand: a randomized controlled trial

BACKGROUND

Reductions in iodine and zinc deficiencies and improvements in hemoglobin were achieved from a micronutrient-fortified seasoning powder consumed in school lunches by children in northeast Thailand.

OBJECTIVE

The objective was to determine whether fortification with 4 micronutrients in a school lunch results in changes in children's growth, morbidity, and cognitive function compared with no fortification.

DESIGN

In a randomized controlled trial of 569 children aged 5.5-13.4 y from 10 schools, we compared the efficacy of a seasoning powder fortified with or without 5 mg Fe, 5 mg Zn, 50 mug I, and 270 mug vitamin A per serving consumed with a school lunch 5 d/wk. Here we report on results of the secondary functional outcomes.

RESULTS

The groups were comparable concerning compliance and loss to follow-up. The intervention had no statistically significant effect on anthropometric measures over 31 wk, but reduced the incidence of respiratory-related illnesses [rate ratio (RR): 0.83; 95% CI: 0.73, 0.94], symptoms of runny nose (RR: 0.80; 95% CI: 0.70, 0.92), cough (RR: 0.80; 95% CI: 0.66, 0.96), and diarrhea (RR: 0.38; 95% CI: 0.16, 0.90). For the visual recall test, those in the fortified group recalled 0.5 more items (95% CI: 0.1, 0.9) than did the controls. There were no statistically significant differences between groups in the results of the digits forward and backward tests or in school grades at the conclusion of the 2 semesters.

CONCLUSION

The beneficial effects on morbidity and visual recall over a short period, in addition to some biochemical improvements, highlight the potential of this micronutrient-fortified seasoning powder supplied in a school lunch. This trial was registered at clinical trials.gov as ACTRN12605000341628.

Effect of Daily versus Once-Weekly Home Fortification with Micronutrient Sprinkles on Hemoglobin and Iron Status among Young Children in Rural Bangladesh

Background

The effectiveness of commonly suggested public health interventions to control childhood iron- deficiency anemia has been low.

Objective

To determine whether iron provided in Sprinkles daily or in a higher dose once weekly affected hemoglobin, serum ferritin levels, and serum transferrin receptor levels, and to determine whether there were dif- ferences in the effects of the two regimens.

Methods

In this cluster-randomized, community- based trial conducted in rural areas of Bangladesh, 136 children aged 12 to 24 months with mild to moderate anemia (hemoglobin 70–109 g/L) were randomly allo- cated to receive Sprinkles daily (12.5 mg of elemental iron, n = 79) or once weekly (30 mg of elemental iron, n = 73) for 8 weeks. Hemoglobin, serum ferritin, and serum transferrin receptor were assessed at the start and end of the intervention.

Results

In both groups, there were significant increases in hemoglobin and serum ferritin and a significant decrease in serum transferrin receptor ( p < .01). There were no significant differences between the groups in the increases in hemoglobin (16.1 ± 13.2 g/L for the group receiving Sprinkles daily and 12.3 ± 13.3 g/L for the group receiving Sprinkles once weekly) and serum ferritin (10.6 and 5.7 μg/L, respectively). The decrease in serum transferrin receptor also did not significantly differ between the groups (median, −2.5 and −1. 8 mg/L, respectively). The prevalence rates of iron-deficiency anemia, depleted iron stores, and tissue iron deficiency decreased significantly within each group ( p < .01), with no significant differences between the groups.

Conclusions

Home fortification of complementary foods with Sprinkles given either daily or once weekly improved iron-deficiency anemia and iron status among young children.

From chronobiology to chronotherapeutics

Chronobiology focuses on variations in biological rhythms across time. This article describes biologic cycles, particularly circadian cycles and their underlying neuroanatomy. Metabolic rhythms are reviewed and their impact on disease and symptom variation discussed. Clinical and chronopharmacological implications and diagnostic applications are presented, highlighting chronotherapy's perspective.