An overview of evidence for a causal relation between iron deficiency during development and deficits in cognitive or behavioral function

Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA, USA.
American Journal of Clinical Nutrition (Impact Factor: 6.77). 04/2007; 85(4):931-45.
Source: PubMed


This review, intended for a broad scientific readership, summarizes evidence relevant to whether a causal relation exists between dietary iron deficiency with (ID+A) or without (ID-A) anemia during development and deficits in subsequent cognitive or behavioral performance. An overview of expert opinion and major evidence in humans and animals is provided. Cognitive and behavioral effects observed in humans with ID-A and in animals with ID+/-A are provided in tables. The degree to which 5 conditions of causality are satisfied and whether deleterious effects of ID-A might be expected to occur are discussed. On the basis of the existing literature, our major conclusions are as follows. Although most of the 5 conditions of causality (association, plausible biological mechanisms, dose response, ability to manipulate the effect, and specificity of cause and effect) are partially satisfied in humans, animals, or both, a causal connection has not been clearly established. In animals, deficits in motor activity are consistently associated with severe ID+A, but adverse effects on performance in tests that target cognitive function have not been clearly shown. Resistance to iron treatment was observed in most trials of children <2 y of age with ID+A, but not in older children. Similar observations were made in rodents when ID+A occurred before rather than after weaning. In children >2 y of age and in adolescents with ID-A, evidence suggests cognitive or behavioral deficits; however, the surprisingly small number of studies conducted in either humans or animals prevents a thorough assessment.

Full-text preview

Available from:
  • Source
    • "iron deficiency associated with fatigue in menstruating women [19] ; with impaired physical performance in female athletes and with reversible cognitive and behavioural deficits in early infant development [20]. Maternal iron deficiency is associated with low neonatal iron stores in the neonate [21] and it has been suggested that the period of particular vulnerability for iron deficiency in the fetus and newborn is between the last trimester and the first two years of life [22]. The epidemiology and natural history of the condition, including development from latent to declared disease, should be adequately understood and there should be a detectable risk factor, disease marker, latent period or early symptomatic stage "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Iron deficiency anaemia is a common problem in pregnancy despite national recommendations and guidelines for treatment. The aim of this study was to appraise the evidence against the UK National Screening Committee (UKNSC) criteria as to whether a national screening programme could reduce the prevalence of iron deficiency anaemia and/or iron deficiency in pregnancy and improve maternal and fetal outcomes. Methods: Search strategies were developed for the Cochrane library, Medline and Embase to identify evidence relevant to UK National Screening Committee (UKNSC) appraisal criteria which cover the natural history of iron deficiency and iron deficiency anaemia, the tests for screening, clinical management and evidence of cost effectiveness. Results: Many studies evaluated haematological outcomes of anaemia, but few analysed clinical consequences. Haemoglobin and ferritin appeared the most suitable screening tests, although future options may follow recent advances in understanding iron homeostasis. The clinical consequences of iron deficiency without anaemia are unknown. Oral and intravenous iron are effective in improving haemoglobin and iron parameters. There have been no trials or economic evaluations of a national screening programme for iron deficiency anaemia in pregnancy. Conclusions: Iron deficiency in pregnancy remains an important problem although effective tests and treatment exist. A national screening programme could be of value for early detection and intervention. However, high quality studies are required to confirm whether this would reduce maternal and infant morbidity and be cost effective.
    Full-text · Article · Dec 2015 · BMC Pregnancy and Childbirth
  • Source
    • "The World Health Organization (WHO) defines anemia as hemoglobin concentrations that are below recommended thresholds [3] [5]. The main causes of anemia are dietary iron deficiency; infectious diseases such as malaria, hookworm infections, and schistosomiasis; deficiencies of other key micronutrients including folate, vitamin B12, and vitamin A; or inherited conditions that affect red blood cells (RBCs), such as thalassaemia [6]. The prevalence of anemia during pregnancy is quite high (42%) globally and above 57.1% in Africa, signifying it as a severe public health problem in the region [3]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Anemia is a major public health problem worldwide. In Ethiopia, a nationally representative and consistent evidence is lacking on the prevalence and determinants during pregnancy. We conducted an in-depth analysis of demographic and health survey for the year 2011 which is a representative data collected from all regions in Ethiopia. Considering maternal anemia as an outcome variable, predicting variables from sociodemographic, household, and reproductive/obstetric characteristics were identified for analyses. Logistic regression model was applied to identify predictors at P < 0.05 . The prevalence of anemia among pregnant women was 23%. Maternal age, region, pregnancy trimester, number of under five children, previous history of abortion (termination of pregnancy), breastfeeding practices, and number of antenatal care visits were key independent predictors of anemia during pregnancy. In conclusion, the level of anemia during pregnancy is a moderate public health problem in Ethiopia. Yet, special preventive measures should be undertaken for pregnant women who are older in age and having too many under five children and previous history of abortion. Further evidence is expected to be generated concerning why pregnant mothers from the eastern part of the country and those with better access to radio disproportionately develop anemia more than their counterparts.
    Full-text · Article · Sep 2015 · Anemia
  • Source
    • "There is considerable evidence about the important role of iron in cognitive, behavioral, and motor development (Beard 2001). It is a component of many enzymes involved in neurotransmitter synthesis, and in iron deficiency (ID), due to decreased activity of associated enzymes, monoamine neurotransmitter systems may be affected (McCann and Ames 2007). A decrease in brain iron concentration is accompanied by changes in serotonergic and dopaminergic systems, in cortical fiber conduction, and myelogenesis (Erikson et al. 2001).Viteri (1998)stated that the tragedy of ID is that unless it is severe and prolonged enough to cause anemia, it is silent, not being evident by clinical signs, and therefore ID must be prevented before anemia is detected. "

    Full-text · Article · Jan 2015
Show more