Resumen

BELTRAN-NAVARRO, Beatriz; MATUTE, Esmeralda  y  VASQUEZ-GARIBAY, Edgar M.. Effect of iron deficiency on neuropsychological development in infants. Interdisciplinaria [online]. 2019, vol.36, n.2, pp.129-150. ISSN 1668-7027.  http://dx.doi.org/10.16888/interd.2019.36.2.9.

Iron is involved in various aspects related to brain function, including oxygen transport, neurotransmitters metabolism, DNA synthesis, ATP production, dendritic growth, axonal development and transport, myelin production, glial development, in plasticity markers such as the brain-derived growth factor, and in synaptic plasticity. Human development (biological, cognitive, social) is associated with a bidirectional and dynamic interaction between gene activity, neural activity and environment. An environmental variable is nutrition, and it is known that the central nervous system is extremely vulnerable to nutritional deficiencies during pregnancy and in the first two years of life, period in which an accelerated maturational dynamism occurs. Therefore, a disturbance of these by an iron deficiency would result in neuropsychological alterations, with varied expressions depending on the age at which it occurs and the severity and duration of the nutritional disease. Iron deficiency is defined as the depletion of iron reserves in the body by various factors (nutritional, physiological, pathological, etc.). Three stages of the illness have been established: iron depletion, iron deficiency without anemia and iron deficiency anemia. The first is associated with a decrease in iron reserves without reaching the deficiency; it may be due to a reduction in iron intake and or absorption, excessive loss or an increase in iron requirements. At this stage, there are no functional consequences in the organism. The second stage, is characterized by biochemical changes that reflect a pathologically reduced concentration of serum ferritin with a normal hemoglobin concentration. Finally, iron deficiency anemia is defined by the combination of low concentration of serum ferritin and hemoglobin. Given that iron deficiency is the most prevalent childhood nutritional disorder in the world (affecting 43 % of children aged 6-59 months) and that it impacts brain maturation and the consequent cognitive, linguistic, motor and behavioral development of those who suffer from it, in this paper, the literature on the effect of iron deficiency on neuropsychological development in infants is analyzed in depth. The review was performed considering the short, medium and long lasting effects of iron deficiency without anemia, iron deficiency anemia, chronic iron deficiency during the first two years of life and the presence of treatment. To contextualize, the analysis of the relationship between iron and brain functioning is included and the variables that modulate the expression of its effect are addressed. To carry out the search of literature regarding the effect of iron deficiency on neuropsychological development in infants, Pubmed and SciELO were consulted. No date or language restriction was established. Different combinations of terms were used: “iron deficiency infant”, “iron deficiency fetal”, “iron deficiency neonatal”, “iron deficiency long lasting”. The analyzed reports fulfilled the following inclusion criteria: a) primary sources, b) establish a value of hemoglobin and at least one of iron (i.e, serum ferritin, mean corpuscular volume, free erythrocyte, protoporphyrin, transferrin saturation) to define the children of each group, c) human sample, d) description of the measures used for the evaluation, e) studies examined after this stage, had to determine that the sample evaluated presented iron deficiency during the first two years of life. In this paper, 51 original articles conducted in humans were analyzed, of which 49 were obtained through Pubmed and 2 from SciELO. It should be noted that, in order to discuss the findings of these reports, literature was included on the effect of iron deficiency using animal models, as well as studies in humans with typical development. The search for these was done at convenience. The recognition of its implications would facilitate the therapeutic work, as well as the inclusion of early stimulation programs together with the management of nutritional deficiency.

Palabras clave : Iron; Anemia; Infants; Central nervous system; Neuropsychological development.

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