Randomised study of cognitive effects of iron supplementation in non-anaemic iron-deficient adolescent girls A Study of the Effects of Latent Iron Deficiency on Measures of Cognition: A Pilot Randomised Controlled Trial of Iron Supplementation in Young Women The effect of iron deficiency and mental stimulation on Indonesian children's cognitive performance and development. Inconsistent Effects of Iron-Folic Acid and/or Zinc Supplementation on the Cognitive Development of Infants Iron treatment normalizes cognitive functioning in young women. Effects of iron supplementation twice a week on attention score and haematologic measures in female high school students. Impact of iron supplementation on cognitive functions in preschool and school-aged children: the Indian experience. Improvements in Iron Status and Cognitive Function in Young Women Consuming Beef or Non-Beef Lunches Once-weekly and 5-days a week iron supplementation differentially affect cognitive function but not school performance in Thai children. Effects of iron supplementation of low-birth-weight infants on cognition and behavior at 7 years: a randomized controlled trial Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials Cognitive deficits in iron-deficient and iron-deficient anemic children. Behavioural responses of young anaemic Indian children to iron-folic acid supplements. Effects of iron supplementation and nutrition education on haemoglobin, ferritin and oxidative stress in iron-deficient female adolescents in Palestine: randomized control trial. Effects of Iron Supplementation of LBW Infants on Cognition and Behavior at 3 Years The efficacy of micronutrient supplementation in reducing the prevalence of anaemia and deficiencies of zinc and iron among adolescents in Sri Lanka Efficacy of Iron and/or Zinc Supplementation on Cognitive Performance of Lead-Exposed Mexican Schoolchildren: A Randomized, Placebo-Controlled Trial
BACKGROUND Up to 25 % of adolescent girls in the USA are iron deficient . This double-blind , placebo-controlled clinical trial assessed the effects of iron supplementation on cognitive function in adolescent girls with non-anaemic iron deficiency . METHODS 716 girls who enrolled at four Baltimore high schools were screened for non-anaemic iron deficiency ( serum ferritin < or = 12 micrograms/L with normal haemoglobin ) . 98 ( 13.7 % ) girls had non-anaemic iron deficiency of whom 81 were enrolled in the trial . Participants were r and omly assigned oral ferrous sulphate ( 650 mg twice daily ) or placebo for 8 weeks . The effect of iron treatment was assessed by question naires and haematological and cognitive tests , which were done before treatment started and repeated after the intervention . We used four tests of attention and memory to measure cognitive functioning . Intention-to-treat and per- protocol analyses were done . FINDINGS Of the 81 enrolled girls with non-anaemic iron deficiency , 78 ( 96 % ) completed the study ( 39 in each group ) . Five girls ( three control , two treatment ) developed anaemia during the intervention and were excluded from the analyses . Thus , 73 girls were included in the per- protocol analysis . Ethnic distribution , mean age , serum ferritin concentrations , haemoglobin concentrations , and cognitive test scores of the groups did not differ significantly at baseline . Postintervention haematological measures of iron status were significantly improved in the treatment group ( serum ferritin 27.3 vs 12.1 micrograms/L , p < 0.001 ) . Regression analysis showed that girls who received iron performed better on a test of verbal learning and memory than girls in the control group ( p < 0.02 ) . INTERPRETATION In this urban population of non-anaemic iron-deficient adolescent girls , iron supplementation improved verbal learning and memory Rates of iron deficiency are high amongst healthy young women .  Cognitive impairment occurs secondary to iron deficiency in infants and children , but evaluation of the impact on cognition among young women is inconsistent . The aim was to determine the suitability of the IntegNeuro test battery for assessing cognitive function in iron-deficient and iron-sufficient young women . A pilot double-blinded , placebo-controlled intervention trial was conducted in iron-deficient ( serum ferritin ≤ 20 μg/L and haemoglobin > 120 g/L ) and iron-sufficient young women ( 18–35 years ) . Cognitive function and haematological markers of iron status were measured at baseline and follow-up . Iron-deficient participants ( n = 24 ) were r and omised to receive placebo , 60 mg or 80 mg elemental iron daily supplements for 16 weeks . A control group of iron-sufficient participants ( n = 8) was allocated to placebo . Change scores for Impulsivity and Attention were significantly greater in plasma ferritin improvers than in non-improvers ( p = 0.004 , p = 0.026 ) . IntegNeuro was easy to administer and acceptable to young women . Based on the differences in Memory and Attention scores between iron-deficient participants on iron treatment and those on placebo , it was decided that between 26 and 84 participants would be required in each iron treatment group for an adequately powered extension of this pilot RCT Three studies conducted in Indonesia will be described . Soewondo ( 12 ) investigated the relation of iron deficiency and cognitive function and impact of iron supplementation on verbal intelligence , attention and concept learning among iron deficient children without anemia and iron deficient anemic children . Half of 176 children , aged 3 - 6 years , received elemental Fe for 8 weeks and the other half received  placebo . There were significant changes from pre to post intervention evaluations in ferritin , transferrin saturation , free erythrocyte protoporphyrin , and hemoglobin in the iron deficient anemic children . Pre and post treatment psychological test data showed that iron deficiency anemia produced alterations in cognitive processes related to visual attention and concept acquisition . These alterations can be reversed with iron treatment . Idjradinata ( 4 ) assessed the impact of iron supplementation on iron deficient infant 's mental and psychomotor development . Hundred twenty six subjects aged 12 to 18 month were r and omly assigned to either iron treatment or placebo intervention . After 4 months of iron supplementation , the hemoglobin , ferritin and transferrin saturation changed significantly in the iron deficient infants . A developmental delay was observed in the iron deficient anemic infants before intervention and the conditions were reversed after 4 months of iron treatment . Soemiarti ( 8) examined the effectiveness of a  training course  given to mothers of children aged 12 to 24 month on the rearing environment and consequently to the child 's development .  The subjects were 69 mothers of 20 - 35 years old . The training lasted for 21 days by giving mothers training using the program " Ibu Maju Anak Bermutu " . The rearing environment improved , also the child 's mental and psychomotor development Despite concerns over the neurocognitive effects of micronutrient deficiencies in infancy , few studies have examined the effects of micronutrient supplementation on specific cognitive indicators . This study investigated , in 2002 , the effects of iron-folic acid and /or zinc supplementation on the results of Fagan Test of Infant Intelligence ( FTII ) and the A-not-B Task of executive functioning among 367 Nepali infants living in Sarlahi district . Infants were enrolled in a cluster-r and omized , placebo-controlled clinical trial of daily supplementation with 5 mg of zinc , 6.25 mg of iron with 25 µg of folic acid , or zinc-iron-folic acid , or placebo . These were tested on both the tasks using five indicators of information processing : preference for novelty ( FTII ) , fixation duration ( FTII ) , accelerated performance ( ≥85 % correct ; A-not-B ) , deteriorated performance ( < 75 % correct and > 1 error on repeat-following-correct trails ; A-not-B ) , and the A-not-B error ( A-not-B ) . At 39 and 52 weeks , 247 and 333 infants respectively attempted the cognitive tests ; 213 made an attempt to solve both the tests . The likelihood of females completing the A-not-B Task was lower compared to males when cluster r and omization was controlled [ odds ratio=0.67 ; 95 % confidence interval 0.46 - 0.97 ; p<0.05 ] . All of the five cognitive outcomes were modelled in linear and logistic regression . The results were not consistent across either the testing sessions or the information-processing indicators . Neither the combined nor the individual micronutrient supplements improved the performance on the FTII or the A-not-B Task ( p>0.05 ) . These findings suggest that broader interventions ( both in terms of scope and duration ) are needed for infants who face many biological and social stressors BACKGROUND Evidence suggests that brain iron deficiency at any time in life may disrupt metabolic processes and subsequently change cognitive and behavioral functioning . Women of reproductive age are among those most vulnerable to iron deficiency and may be at high risk for cognitive alterations due to iron deficiency . OBJECTIVE We aim ed to examine the relation between iron status and cognitive abilities in young women . DESIGN A blinded , placebo-controlled , stratified intervention study was conducted in women aged 18 - 35 y of varied iron status who were r and omly assigned to receive iron supplements or a placebo .  Cognition was assessed by using 8  cognitive performance tasks  ( from Detterman 's Cognitive Abilities Test ) at baseline ( n = 149 ) and after 16 wk of treatment ( n = 113 ) . RESULTS At baseline , the iron-sufficient women ( n = 42 ) performed better on cognitive tasks ( P = 0.011 ) and completed them faster ( P = 0.038 ) than did the women with iron deficiency anemia ( n = 34 ) . Factors representing performance accuracy and the time needed to complete the tasks by the iron-deficient but nonanemic women ( n = 73 ) were intermediate between the 2 extremes of iron status . After treatment , a significant improvement in serum ferritin was associated with a 5 - 7-fold improvement in cognitive performance , whereas a significant improvement in hemoglobin was related to improved speed in completing the cognitive tasks . CONCLUSIONS Iron status is a significant factor in cognitive performance in women of reproductive age . Severity of anemia primarily affects processing speed , and severity of iron deficiency affects accuracy of cognitive function over a broad range of tasks . Thus , the effects of iron deficiency on cognition are not limited to the developing brain INTRODUCTION Iron deficiency , associated with a decline in cognitive function , is the most common nutritional deficiency globally . The present study aim ed to identify the impact of weekly iron supplements on the attention function of female students from a high school in North Khorasan Province , Iran . METHODS This was a blind , controlled , clinical trial study , involving 200 female students who were chosen using the stratified r and omised sampling method . First , laboratory studies were performed to detect iron consumption limitations . Next , the 200 students were divided r and omly and equally into case and control groups . The case group was treated with 50 mg of ferrous sulfate twice a week for 16 weeks . We compared both groups ' data on attention , iron status and erythrocyte indices . Question naires were used to collect demographic data , while clinical data was collected using complete blood count and Toulouse-Piéron tests . Data was analysed using descriptive statistics , as well as paired and independent t-tests . RESULTS The mean attention scores of the case and control groups were 104.8 ± 7.0 and 52.7 ± 9.6 , respectively ( p < 0.001 ) . The mean haemoglobin levels of the two groups were 12.5 ± 0.9 and 11.2 ± 1.0 , respectively ( p < 0.001 ) . Compared to the control group , the attention scores and haemoglobin concentrations of the case group were found to be improved by approximately 90 % and 10 % , respectively . CONCLUSION Oral iron supplements ( 50 mg twice a week for 16 weeks ) were able to improve the attention span and haematologic indices of female high school students Four studies examined impacts of iron supplementation on school children of various ages and both sexes . The first study investigated impact of iron-folic acid supplements for 60 d on cognition in 94 boys and girls aged 5 - 8 y. Improvement in total scores of the anemics was significantly higher than the nonanemics in 7 - 8-y-old children only . The second study assessed impacts of supplementation on cognition in 14 pairs of 5 - 6-y-old anemic boys , with clear beneficial effects on cognitive function . The third study investigated effects of varying dosages of elemental iron on cognitive function in 48 boys aged 8 - 15 y , with different levels of improvement . The fourth study investigated impacts of iron supplementation on 163 anemic girls aged 8 - 15 y with treatment and evaluations at 4 and 8 mo , with significantly improved scores in cognitive function after the eighth month Iron status is associated with cognitive performance and intervention trials show that iron supplementation improves mental function in iron-deficient adults . However , no studies have tested the efficacy of naturally iron-rich food in this context . This investigation measured the hematologic and cognitive responses to moderate beef consumption in young women . Participants ( n = 43 ; age 21.1 ± 0.4 years ) were r and omly assigned to a beef or non-beef protein lunch group [ 3-oz ( 85 g ) , 3 times weekly ] for 16 weeks . Blood was sample d at baseline , and weeks 8 and 16 , and cognitive performance was measured at baseline and week 16 . Body iron increased in both lunch groups ( p < 0.0001 ) , with greater improvement demonstrated in women with lower baseline body iron ( p < 0.0001 ) . Body iron had significant beneficial effects on spatial working memory and planning speed ( p < 0.05 ) , and ferritin responders ( n = 17 ) vs. non-responders ( n = 26 ) showed significantly greater improvements in planning speed , spatial working memory strategy , and attention ( p < 0.05 ) . Lunch group had neither significant interactions with iron status nor consistent main effects on test performance . These findings support a relationship between iron status and cognition , but do not show a particular benefit of beef over non-beef protein consumption on either measure in young women 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 , r and omized , placebo-controlled trial was conducted . Primary schoolchildren ( n = 397 ) were r and omly assigned to receive iron supplements daily or weekly or placebo . Ferrous sulfate ( 300 mg ) or placebo tablets were given under direct observation by the research er 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 Background Low-birth-weight infants ( LBW ) are at an increased risk of iron deficiency that has been associated with impaired neurodevelopment . We hypothesized that iron supplementation of LBW infants improves cognitive scores and reduces behavioral problems until school age . Methods We r and omized 285 marginally LBW ( 2,000–2,500 g ) infants to receive 0 , 1 , or 2 mg/kg/day of iron supplements from 6 weeks to 6 months of age . At 7 years of age , 205 participants were assessed regarding cognition using Wechsler Intelligence Scale for Children ( WISC-IV ) and behavior using the parental question naires Child Behavior Checklist ( CBCL ) and Five  to Fifteen  ( FTF ) . Results There were no significant differences between the intervention groups in WISC-IV or FTF . However , the CBCL scores for externalizing problems were significantly different , in favor of supplemented children ( P=0.045 ) . When combining the supplemented groups , they had significantly lower scores for externalizing behavior compared with placebo ( median ( interquartile range ) : 44 [ 34;51 ] vs. 48.5 [ 41;56 ] P=0.013 ) , and their risk ratio ( 95 % confidence interval ) for a total behavioral score above the cutoff for clinical problems was 0.31 ( 0.09–1.0 ) , P=0.054 . Conclusion Lower scores of externalizing behavior in supplemented children support our previous findings at 3 years , and suggest that iron supplementation may have long-lasting effects on behavioral functions Objective Iron supplementation in iron-deficiency anaemia is st and ard practice , but the benefits of iron supplementation in iron-deficient non-anaemic ( IDNA ) individuals remains controversial . Our objective is to identify the effects of iron therapy on fatigue and physical capacity in IDNA adults . Design Systematic review and meta- analysis of r and omised controlled trials ( RCTs ) . Setting Primary care . Participants Adults ( ≥18 years ) who were iron deficient but non-anaemic . Interventions Oral , intramuscular or intravenous iron supplementation ; all therapy doses , frequencies and duration s were included . Comparators Placebo or active therapy . Results We identified RCTs in Medline , Embase , Cochrane Central Register of Controlled Trials , Cumulative Index of Nursing and Allied Health , SportD iscus and CAB Abstract s from inception to 31 October 2016 . We search ed the WHO ’s International Clinical Trials Registry Platform for relevant ongoing trials and performed forward search es of included trials and relevant review s in Web of Science . We assessed internal validity of included trials using the Cochrane Risk of Bias tool and the external validity using the Grading of Recommendations Assessment , Development and Evaluation methodology . From 11 580 citations , we included 18 unique trials and 2 companion papers enrolling 1170 patients . Using a Mantel-Haenszel r and om-effects model , iron supplementation was associated with reduced self-reported fatigue ( st and ardised mean difference ( SMD ) −0.38 ; 95 % CI −0.52 to −0.23 ; I2 0 % ; 4 trials ; 714 participants ) but was not associated with differences in objective measures of physical capacity , including maximal oxygen consumption ( SMD 0.11 ; 95 % CI −0.15 to 0.37 ; I2 0 % ; 9 trials ; 235 participants ) and timed methods of exercise testing  . Iron supplementation significantly increased serum haemoglobin concentration ( MD 4.01 g/L ; 95 % CI 1.22 to 6.81 ; I2 48 % ; 12 trials ; 298 participants ) and serum ferritin ( MD 9.23 µmol/L ; 95 % CI 6.48 to 11.97 ; I2 58 % ; 14 trials ; 616 participants ) . Conclusion In IDNA adults , iron supplementation is associated with reduced subjective measures of fatigue but not with objective improvements in physical capacity . Given the global prevalence of both iron deficiency and fatigue , patients and practitioners could consider consumption of iron-rich foods or iron supplementation to improve symptoms of fatigue in the absence of documented anaemia . PROSPERO registration number CRD42014007085 Eighteen- to 60-month-old iron-deficient anemic children given iron therapy ( n = 25 ) and a control group matched for mother 's educational level showed no significant difference in mean mental development score at baseline . The control group 's mean score was increased significantly over baseline score at 3 and 6 months and was significantly higher than the experimental group 's mean score at 3 months . Although the experimental group demonstrated hematologic correction over 6 months , mean mental development score showed no significant improvement . Scores for an iron deficient not anemic group given iron ( n = 22 ) , despite complete hematologic correction over the six months of observation , and for its control group , did not change significantly . Baseline scores for an iron-deficient not anemic placebo group ( n = 23 ) and for its control group were not significantly different . At 3 months the control group score had increased significantly , whereas that for the experimental group had not . When experimental and control subjects were matched on baseline mental development score , the control subjects experienced increases in scores over time , further confirming an impaired ability to improve scores with repeated testing in the experimental groups . Behavioral rating data ( responsiveness to examiner , responsiveness to environment , and emotional tone ) revealed significant differences between the iron-deficient anemic group and its control group at 3 and 6 months , with the control group rated more responsive , suggesting that iron deficiency , alone or in association with anemia , may have some lasting effect on behavior and development . Group differences were also found between the mean number of occurrences of multiple stressful events . Failure to show improvement in scores in the iron-deficient anemic group may reflect the fact that those children were less testable than were children in the control group , despite repeated testings , a theory supported by the infant behavior rating data . This may be related to some irreversible behavioral deficit or to an adverse environmental milieu ( e.g. , stress ) 1 . Behavioural responses of young anaemic Indian children to iron-folic acid supplements were assessed in two separate studies using the Indian adaptation of Wechsler 's ( 1967 ) intelligence scale for children ( WISC ) . 2 . The first study was an exploratory study in which the cognitive behaviour of 5 - 8-year-old children of both sexes was assessed before and after supplementation with 20 mg elemental Fe and 0.1 mg folic acid given daily for a period of 60 d. 3 . The supplemented children showed a significant improvement in haemoglobin ( Hb ) as well as the WISC scores while the control children who did not receive any supplements failed to show an improvement either in Hb or in the WISC scores . However , within the supplemented group when the initially-anaemic children were compared with the initially-non-anaemic ones , only the 7-year-old anaemic children performed significantly poor in the tests than the non-anaemic group of the same age . The study raised the possibility that in addition to increasing the blood Hb levels , Fe-folic acid supplements may have additional benefits in improving the cognitive performance of children . 4 . In the second study , cognitive behaviour of fourteen matched pairs of anaemic children in the age-range of 5 - 6 years was assessed before and after supplementation with 40 mg Fe and 0.2 mg folic acid given daily in two divided doses or sugar placebos for a period of 60 d. The tester did not know the groups to which each child belonged . 5 . The supplemented children showed a significant improvement in Hb as well as in the verbal and performance IQ of WISC . The control children showed no improvement in Hb but their verbal IQ improved significantly . However , there was no significant improvement in their performance IQ . 6 . The results indicated that Fe-folic acid supplements to anaemic children not only raised Hb levels but also improved intelligence test results , particularly in the performance section Background Iron deficiency and iron-deficiency anaemia are associated with oxidative stress , but their role is largely unclear . Information is scarce on the effects of iron supplementation on biomarkers of oxidative stress in humans . Aims This study evaluated the effectiveness of iron supplementation and nutrition education on improving the levels of haemoglobin and ferritin , and decreasing oxidative stress among iron-deficient female adolescents in Gaza , Palestine . Methods A total 131 iron-deficient female adolescents were recruited and allocated r and omly into 3 different groups . The iron supplementation group ( A ) received 200 mg of ferrous fumarate weekly during the 3-month intervention , the iron supplementation with nutrition education group ( B ) received iron supplements with nutrition education sessions , and the control group ( C ) did not receive any intervention . The levels of haemoglobin , ferritin and malonyl dialdehyde were measured at baseline , after 3 months ( at which point the intervention was stopped ) , and then 3 months later . Trial registration number : ACTRN12618000960257 . Results Haemoglobin levels increased significantly after supplementation in both groups A and B. At the follow-up stage ( 3 months after stopping the intervention ) , iron and haemoglobin levels in group B continued to increase and malonyl dialdehyde decreased . In Group A , haemoglobin , ferritin and malonyl dialdehyde levels decreased after 3 months of stopping the intervention . No changes were seen in Group C. Conclusions A nutrition programme should be adopted and integrated into comprehensive intervention programmes to target iron-deficiency anaemia among female adolescents in Palestine OBJECTIVE : Low birth weight ( LBW ) infants are at increased risk of cognitive and behavioral problems and at risk for iron deficiency , which is associated with impaired neurodevelopment . We hypothesized that iron supplementation of LBW infants would improve cognitive scores and reduce behavioral problems . METHODS : In a r and omized controlled trial , 285 marginally LBW ( 2000–2500 g ) infants received 0 , 1 , or 2 mg/kg/day of iron supplements from 6 weeks to 6 months of age . At 3.5 years of age , these infants and 95 normal birth weight controls were assessed with a psychometric test ( Wechsler Preschool and Primary Scale of Intelligence ) and a question naire of behavioral problems ( Child Behavior Checklist ; CBCL ) . RESULTS : There were no significant differences in IQ between the LBW groups or LBW infants versus controls  .  Mean ( SD ) full-scale IQ was 105.2 ( 14.5 ) , 104.2 ( 14.7 ) , and 104.5 ( 12.7 ) in the placebo , 1 mg , and 2 mg groups , respectively ( P = .924 ) . However , for behavioral problems , there was a significant effect of intervention . The prevalence of children with CBCL scores above the US sub clinical cutoff was 12.7 % , 2.9 % , and 2.7 % in the placebo , 1-mg , and 2-mg groups , respectively ( P = .027 ) , compared with 3.2 % in controls . Relative risk ( 95 % confidence interval ) for CBCL score above cutoff in placebo-treated children versus supplemented was 4.5 ( 1.4–14.2 ) . CONCLUSIONS : Early iron supplementation of marginally LBW infants does not affect cognitive functions at 3.5 years of age but significantly reduces the prevalence of behavioral problems . The study suggests a causal relation between infant iron deficiency and later behavioral problems Objective : To determine the effectiveness of combined iron and zinc over the iron or zinc-only supplementation in correcting deficiency and possible interactive effects in a group of adolescent school children . Subjects and methods : Schoolchildren ( n=821 ) of 12–16 years of age were r and omized into four groups and supplemented with iron ( 50 mg/day ) , zinc ( 14 mg/day ) , iron+zinc or placebo capsules 5 days per week for 24 weeks . Anthropometry , and haemoglobin ( Hb ) , serum zinc ( SZn ) and serum ferritin ( SF ) concentrations were determined before and after the intervention . Results : There were no significant effects between-groups in their weight , height and Hb concentrations with the intervention when compared with the placebo group . Iron-only and combination-supplemented groups had reached mean SF concentrations of 55.1 μg/l with no difference between them ( P=0.99 ) . The zinc-only group had a mean change of 4.3 μmol//l whereas the combine-supplemented group had a mean change of 4.0 μmol/l ( P=0.82 ) . The prevalence of anaemia was found to be 70.3 % in the iron group at baseline ; this was reduced to 14.5 % after the supplementation . In the combine-supplemented group anaemia , prevalence was reduced from 64.8 to 19.3 % . Conclusions : Zinc alone or in combination with iron has not shown a significant improvement in growth in adolescence . Severe and moderate forms of anaemia were successfully treated in children who received iron supplementation . Initial high prevalence of low SZn and iron stores was significantly improved with micronutrient supplementation OBJECTIVE . Lead exposure in children has been associated with both global and specific cognitive deficits . Although chelation therapy is advised for children with blood lead concentrations of > 44 μg/dL , treatment options for children with lower blood lead values are limited . Because lead absorption is related to children 's nutritional status , micronutrient supplements may be 1 strategy for combating low-level , chronic lead exposure . This study was design ed to test the efficacy of iron and zinc supplementation for lowering blood lead concentrations and improving cognitive performance in schoolchildren who live in a lead-contaminated city . METHODS . This r and omized , double-blind , placebo-controlled field trial was conducted in public elementary schools in Torreón , an industrialized city in northern Mexico . A metal foundry , located close to the city center and within 3.5 km of 9 schools , was the main source of lead exposure . A total of 602 children who were aged 6 to 8 years and regularly attending first grade in the study schools were enrolled . Children were given 30 mg of iron , 30 mg of zinc , both , or a placebo daily for 6 months . A total of 527 completed the treatment , and 515 were available for long-term follow-up , after another 6 months without supplementation . Eleven cognitive tests of memory , attention , visual-spatial abilities , and learning were administered at baseline and each follow-up . RESULTS . There were no consistent or lasting differences in cognitive performance among treatment groups . CONCLUSIONS . Daily supplementation with iron and /or zinc may be of limited usefulness for improving cognition in lead-exposed schoolchildren . However , these treatments may be effective in setting s with higher prevalence of nutritional deficiencies or in younger children
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 .
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 r and omised controlled trials ( RCTs ) .
Aim To assess whether iron supplementation improved cognitive domains : concentration , intelligence , memory , psychomotor skills and scholastic achievement .