Iodine deficiency: No longer just a third-world issue, warns study
The re-emergence of iodine deficiency in some industrialised countries has raised concerns over the public health implications and the need for fortification or supplementation programs.
FAB RESEARCH COMMENT:
Iodine is essential for normal brain development via its key role in thyroid function - and yet many people fail to obtain enough of this vital nutrient from their diets.The UK remains virtually the only developed country that still has no public health policy on iodine. (In others, adding iodine to salt or other basic foodtuffs is common practice) And research has shown that supplements for pregnant women would actually be cost-effective.
Mild-to-moderate iodine deficiency during pregancy was found in 2 out of 3 of mothers-to-be in a large UK study - and this predicted significant reductions in both verbal IQ and reading ability in their children. See:
Milk and dairy products, and fish and seafood are the main dietary sources of iodine - so deficiencies are particularly common in vegans, vegetarians and others who don't regularly consume these foods.
Supplements are therefore needed for many people - particularly women before and during pregnancy. However, kelp supplements are NOT recommended as these can provide too much iodine, which can also be harmful.
For more information on the best dietary sources, see the BDA factsheet on iodine (written by authors of this study).
As this latest research shows, much more still needs to be done to ensure that all mothers-to-be have a good dietary supply of iodine - and for the most vulnerable groups, multi-agency action is needed. However, important first steps include raising awareness and improving education on the crucial importance of dietary iodine
- among all women who may be planning - or even considering - pregnancy
- for health professionals, so that appropriate guidance and support to achieve good iodine status becomes part of standard prenatal care
See the new research here (free full text is available online):
And for more information on iodine in pregnancy, see:
The re-emergence of iodine deficiency in some industrialised countries has raised concerns over the public health implications and the need for fortification or supplementation programs.
While much progress has been made to reduce the global incidence of maternal iodine deficiency during pregnancy and lactation, recent studies have identified low maternal iodine status even in areas thought to be iodine sufficient, according to new data published in Nutrients.
Researchers from the University of Surrey, UK, and the Hospital de Riotinto, Huelva, Spain, noted that maternal iodine deficiency during pregnancy and lactation and childhood deficiency during the first two years of life, are widely recognised as having negative cognitive consequences including impaired speech development, learning and reading skills.
The team also identified the emergence of a new scenario whereby impaired cognitive outcomes are augmented by behavioural disorders such as autism or attention-deficit/hyperactivity disorder (ADHD). Recent evidence has indicated an increased risk of ADHD in the offspring of mothers with abnormal serum thyroid hormone concentrations during early pregnancy.
“Iodine is most critical in the early stages of development, as the foetal brain is extremely dependent on iodine supply and cannot be replaced by any other nutrient. So an adequate iodine intake in pregnancy is needed to achieve optimal foetal neurodevelopment,” commented co-author Dr. Inés Velasco from the Paediatrics, Obstetrics and Gynaecology Unit, Hospital de Riotinto.
While much progress has been made to reduce the global incidence of maternal iodine deficiency during pregnancy and lactation, recent studies have identified low maternal iodine status even in areas thought to be iodine sufficient, according to new data published in Nutrients.
Researchers from the University of Surrey, UK, and the Hospital de Riotinto, Huelva, Spain, noted that maternal iodine deficiency during pregnancy and lactation and childhood deficiency during the first two years of life, are widely recognised as having negative cognitive consequences including impaired speech development, learning and reading skills.
The team also identified the emergence of a new scenario whereby impaired cognitive outcomes are augmented by behavioural disorders such as autism or attention-deficit/hyperactivity disorder (ADHD). Recent evidence has indicated an increased risk of ADHD in the offspring of mothers with abnormal serum thyroid hormone concentrations during early pregnancy.
“Iodine is most critical in the early stages of development, as the foetal brain is extremely dependent on iodine supply and cannot be replaced by any other nutrient. So an adequate iodine intake in pregnancy is needed to achieve optimal foetal neurodevelopment,” commented co-author Dr. Inés Velasco from the Paediatrics, Obstetrics and Gynaecology Unit, Hospital de Riotinto.
Laboratory studies have shown that iodine deficiency leads to irreversible disturbances in the cellular structure of the brain’s cerebral cortex, explained the researchers. These disturbances cause abnormal migration of neurons, which is in turn associated with cognitive impairment.
Industrialised countries
Perhaps the most surprising finding was that the perception of iodine deficiency only being a problem in certain areas, or in impoverished conditions, was no longer the reality. “For years, it was believed that iodine deficiency was a problem restricted to certain geographic areas and high-risk conditions (poverty, malnourishment) but this is not valid anymore,” explained Velasco.
“Although the most severe clinical features of perinatal iodine deficiency have been progressively eradicated through salt-iodisation programmes and public strategies of iodine supplementation or fortification, the re-emergence of iodine deficiency in some industrialised countries has reawakened concern about the cognitive consequences of this deficiency”
Continuing education needed
“It is important to elucidate the contribution of iodine deficiency to these emergent public health issues,” said Velasco.“As researchers, we certainly must disseminate the significance of an adequate nutritional iodine status at the beginning of life and throughout the childhood in order to achieve optimal neurodevelopment.”
In order to eliminate perinatal iodine deficiency may require a broad collaborative approach from numerous stakeholders, suuggested Velasco.
“Iodine deficiency remains as a public health problem worldwide and also requires a serious commitment from health authorities to be eradicated.
"Multidisciplinary approaches (scientific community, health care system, public institutions) are needed to guarantee an adequate iodine intake in the most vulnerable populations groups (pregnant women and children under age of 2)," she concluded.
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