Iodine nutrition in infancy and childhood.

iodine is a trace element essential for the synthesis of thyroid hormones. It is present in the human body in minute amounts (15-20 mg in adults). The thyroid is very sensitive to iodine deficiency in newborns and infants because of its very low iodine content. Daily iodine requirements in humans vary from 40 mu g in neonates to 150 mu g in adults. iodine deficiency represents the first cause of avoidable mental deficiency in developed countries; it has not yet disappeared in Europe, especially in the East, where it is responsible for a high prevalence of goiter, iodine deficiency during pregnancy increases the risk of neonatal transient hypothyroidism, with a high recall rate in programs of systematic screening for congenital hypothyroidism. Data available in France suggest that screening for iodine deficiency should be performed during pregnancy and that the minimal iodine concentration in formula milk should be increased to 10 mu g/100 kcal for term infants and 20 mu g/100 kcal for premature infants. iodine deficiency is ideally prevented by the use of iodized salt. Because of the risk of iodine overexposure and secondary transient hypothyroidism, the use of iodinated antiseptics must be avoided in premature babies and neonates as well as in pregnant and lactating women. The fight against iodine deficiency: associated with oral stable preventive iodine administration, decreases sharply the risk of thyroid cancer in case of nuclear exposure, by diminishing thyroid uptake of iodine radioactive isotopes. (C) 2000 Editions scientifiques et medicales Elsevier SAS.