The work developed by a group of researchers from institutions such as the University Institute of Health Sciences – CESPU, the Faculties of Medicine and Pharmacy of the University of Porto, the Faculty of Medical Sciences of the New University of Lisbon, among others, follows another study that had already concluded that iodine deficiency also impairs cognitive development.

In this study, which will be presented today at the International Congress of TOXRUN, Research Unit in Toxicology of the University Institute of Health Sciences – CESPU, the levels of iodine and the Intelligence Quotient (IQ) of about 2,000 children between 5 and 12 years of age from schools in the Northern region were analysed.

Speaking to Lusa, Sandra Leal, one of the researchers involved, warned of the importance of these data to adjust public policies: "[iodine] levels that are above [normal] also have an association with lower IQ."

"Lacking in iodine is bad, but excess may not be very good either," she says.

The range of daily iodine intakes recommended by the World Health Organization (WHO) is established by age and is grouped into four levels: 90 micrograms for children up to 5 years, 120 micrograms for children between 6 and 11 years and 150 micrograms for adolescent adults and the elderly. For pregnant and lactating women, the daily requirements are 250 micrograms.

In this study, researchers concluded that a higher proportion of children with levels above the recommended levels had below-average IQs, the same as had been observed in those with iodine deficiency.

Confessing that the researchers were surprised by these results, Sandra Leal draws attention to the importance of adjusting public health promotion policies according to the characteristics of the population after the diagnosis is made.

"Even promotion policies have to be adjusted to the socio-economic reality [of the population]," she adds.

Iodine is an element essential to the normal functioning of the body and the only way to obtain it is from food, because it is not produced by the body, and serves to keep in balance the metabolic processes of growth and development of the brain and nervous system.

The foods richest in iodine are those of marine origin, such as mackerel, mussels, cod, salmon, hake, cockles or shrimp, but it also exists in milk, egg or liver.