Brain development deficiency

A deficiency of iodine results iu insufficient synthesis of thyroxine and a low plasma level, so that secretion of TSH is increased in an attempt to stimulate synthesis but this results in enlargement of the thyroid gland (goitre). Iodine deficiency in pregnancy impairs brain development in the foetus, causing mental retardation (known as cretinism). Indeed iodine deficiency is one of the major public health issues worldwide an estimated 200 million people are affected. 

Stumpo DJ, Bock CB, Tuttle JS, et al MARCKS deficiency in mice leads to abnormal brain development and perinatal death. Proc Natl Acad Sci USA 92 944-948, 1995... 

Iodine deficiency has its most devastating effects on babies while they are in the womb and during their first three months oflife. These are the critical periods of brain development and lack of iodine leads to irreversible effects and permanent mental retardation and on average such children have an IQ of around 85 compared to the IQ of 100 of children who develop normally. Many exhibit the symptoms of brain damage due to lack of iodine, and this condition affects as many... 

It has long been known that thyroid hormone deficiency, when established prior to the critical period of brain development, produces severe and permanent mental retardation both in humans ( cretinism ) and in experimental animals (see Refs. 6 and 101). Most of the early studies aimed at describing the behavioural, physiolog-... 

Neurological Effects. Severe zinc deficiency is known to affect mental well-being, with varying degrees of confusion and depression being consistent with zinc enzymes having important activity in brain development and function. The history of zinc in relation to the brain and possible relevance to hmnan disease has been reviewed. 

Since iron is involved in many central nervous system processes that could affect infant behaviour and development, iron deficiency has adverse effects on brain development, both pre- and post-natal. In various epidemiological studies, it is reported that children with iron-deficiency anaemia have poorer performances on tests of some specific cognitive function. Animal experiments have identified some of the defects of reduced iron availability on brain function, which include post-translational changes (which result in a failure of iron incorporation into protein structures which are subsequently degraded), vulnerability of the developing hippocampus (with loss of the neuronal metabolic marker cytochrome c oxidase), and altered dendritic stmcture. Iron deficiency will also have a direct effect on myelin, including a decrease in myelin lipids and proteins, as well as neurotransmitter systems, since iron... 

Menon NK, Dhopeshwarkar GA. Essential fatty acid deficiency and brain development. Prog Lipid Res 1982 21 309-326. 

Tominaga, L., Ogawa, Y., Taniguchi, M., Ohno, K., Matsuda, J., Oshima, A., Suzuki, Y., and Nanba, E., Galactonojirimycin derivatives restore mutant human beta-galactosidase activities expressed in fibroblasts from enzyme-deficient knockout mouse, Brain Develop 23 (2001) 284 287. 

Pregnant and lactating women are vulnerable to iodine deficiency if specialized enteral preparations are their sole source of nutrition. Only 9 out of 44 specialized enteral preparations for adults provide the current requirement of 200 pg/day. If the WHO technical consultation presently under review is accepted, then only two preparations will meet the proposed allowance of 250 pg/day. This has particular consequences for the brain development of the fetus and infant if the mother has an iodine deficiency during pregnancy and if she breast-feeds. Generally, standard infant formula are recommended for use by the manufacturers for up to 1 year, but as infants are weaned from approximately 6 months, estimation of iodine intakes can only be approximate as the mixed diet progresses. 

Neonates, and especially preterm infants, are a population at risk of suffering the consequences of iodine deficiency because of the impact of neonatal hypothyroxinemia on brain development. We evaluate the possible association between mental development scores at different ages and iodine intake during the neonatal period. Sixty-seven preterm infants were subdivided into GA groups for data analysis. The mental development scores reported here are those of the Brunet-Lezine scale index for children (0-24 months of age). The children were tested at 6, 9, 12, 18 and 24 months of postnatal age, and results were corrected for their GA. The test assesses P, motor abilities and postural... 

Most preterm babies are at high risk of iodine deficiency neonates, and especially preterm infants, are a very important population at risk of suffering the consequences of both iodine deficiency and excess, because of the impact of neonatal hypothyroxinemia on brain development. 

The history of the problem of iodine deficiency has been analyzed (Hetzel, 1989), and reports from two comprehensive symposia on various aspects of iodine and brain development have been published (DeLong et al., 1989 Stanbury, 1994). 

Three mechanisms have been suggested for the effect of iodine deficiency on fetal brain development. 

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