Maternal iodine deficiency can affect child development

August 11, 2017
Credit: Colourbox.com

A low iodine intake among pregnant women may be associated with poor language development, reduced fine motor skills and behavioural problems when the child is three years old. These are findings from the Norwegian Mother and Child Cohort Study (MoBa).

Iodine is a nutrient needed to produce thyroid hormones, which in turn are essential for brain development.

"We see an association between low iodine intake and language, and behaviour, but not with gross motor skills or the age when the child starts walking," says Anne Lise Brantsæter.

Brantsæter is a researcher at the Norwegian Institute of Public Health. She is leading a project where researchers study how iodine intake from food or from supplement use by is associated with various neurodevelopmental outcomes in children in MoBa.

"We already know that severe in pregnancy is harmful to the foetus but it has been uncertain whether milder deficiency can also have negative consequences," continues Brantsæter, one of the authors of the study published in the Journal of Nutrition.

Many pregnant women have a low iodine intake

Iodine intake was calculated based on a detailed food-frequency questionnaire answered mid-pregnancy by MoBa participants. More than half (63 per cent) of pregnant women in MoBa had a lower iodine intake than recommended (175 μg / day is recommended for pregnant women according to the Nordic Nutrition Recommendations) and many had a significantly lower iodine intake. 17 per cent had an intake below half of the recommended values.

A high prevalence of low iodine intake among pregnant women and women of childbearing age in Norway has been confirmed by other studies. Iodine deficiency is also very common worldwide and the results of this research are relevant to other countries.

Iodine supplements do not seem to protect

"In this study we also looked at whether iodine from supplements is protective, but the results do not suggest this. One possible explanation may be that starting to take an iodine supplement when pregnant may be too late to have beneficial effects," explains Brantsæter.

In MoBa, 30 per cent of pregnant women reported using supplements containing iodine.

Small, yet concerning effects

Although the effects on each child may be minor, with such a high proportion of Norwegian pregnant women having a low iodine intake, the results are of concern.

"If the assumptions for our calculations are correct and the associations we see actually reflect causal relationships, then mild to moderate iodine deficiency is significant for the occurrence of and language delays among Norwegian three-year-olds," says Brantsæter.

"In this kind of study, we can never be entirely sure that the relationships we see really represent causal relationships. Nevertheless, there is much to indicate that these findings should be taken seriously. Our findings are supported by those of other studies, but more research is necessary," she adds.

MoBa well-suited to highlight the problem

Major studies are needed to detect such associations. MoBa is particularly suitable because the study has so many participants and because iodine deficiency is widespread among Norwegian women.

"We have valuable data in MoBa that allow us to look at other brain development goals in children. We are working to look at the risk of ADHD and we will also look at more development goals at eight years of age now that the MoBa children are growing older. Then we can see if the relationships we saw at three years persist," says Brantsæter.

Urgent need for action

The findings in this study support the conclusion in the Nutrition Council's 2016 report on iodine status in Norway that there is an urgent need for measures to ensure an adequate iodine intake in Norway. The report emphasises the need to investigate and assess measures to achieve a satisfactory iodine intake.

"The results show that it is important for pregnant to have an adequate iodine intake before they conceive and that in pregnancy cannot compensate for low intake before pregnancy. However, more research is necessary," concludes Brantsæter.

Explore further: Experts stress need for sufficient iodine nutrition during pregnancy

More information: Marianne H Abel et al. Suboptimal Maternal Iodine Intake Is Associated with Impaired Child Neurodevelopment at 3 Years of Age in the Norwegian Mother and Child Cohort Study, The Journal of Nutrition (2017). DOI: 10.3945/jn.117.250456

Related Stories

Experts stress need for sufficient iodine nutrition during pregnancy

August 27, 2015
New research published in Acta Obstetricia et Gynecologica Scandinavica, a journal of the Nordic Federation of Societies of Obstetrics and Gynecology, found that pregnant women in Sweden had inadequate levels of iodine in ...

Universal iodine supplementation during pregnancy could offer huge cost savings

August 10, 2015
Giving all pregnant women iodine supplements, even in mildly iodine deficient countries like the UK, could result in huge cost savings for health care systems and society, according to new modelling research published in ...

Pregnant women lack guidance on iodine intake levels

May 26, 2015
Pregnant women are not getting enough information about the need to include iodine in their diets, despite high awareness of general advice for pregnancy nutrition.

Are Kiwi men getting enough iodine?

January 29, 2016
Do Kiwi men who sweat a lot suffer from iodine deficiency? That is the question researchers from Massey University's School of Food and Nutrition want to answer as they kick off a new study investigating the iodine levels ...

Iodine in bread not enough for pregnant women

June 18, 2013
(Medical Xpress)—New research from the University of Adelaide shows that iodised salt used in bread is not enough to provide healthy levels of iodine for pregnant women and their unborn children.

Iodine deficiency common in pregnancy, pediatricians warn

May 26, 2014
(HealthDay)—Many pregnant and breast-feeding women are deficient in iodine and should take a daily supplement containing iodide, according to a leading group of pediatricians.

Recommended for you

Breathing dirty air may harm kidneys, study finds

September 21, 2017
Outdoor air pollution has long been linked to major health conditions such as heart disease, stroke, cancer, asthma and chronic obstructive pulmonary disease. A new study now adds kidney disease to the list, according to ...

Excess dietary manganese promotes staph heart infection

September 21, 2017
Too much dietary manganese—an essential trace mineral found in leafy green vegetables, fruits and nuts—promotes infection of the heart by the bacterium Staphylococcus aureus ("staph").

Being active saves lives whether a gym workout, walking to work or washing the floor

September 21, 2017
Physical activity of any kind can prevent heart disease and death, says a large international study involving more than 130,000 people from 17 countries published this week in The Lancet.

Frequent blood donations safe for some, but not all

September 21, 2017
(HealthDay)—Some people may safely donate blood as often as every eight weeks—but that may not be a healthy choice for all, a new study suggests.

Higher manganese levels in children correlate with lower IQ scores, study finds

September 21, 2017
A study led by environmental health researchers at the University of Cincinnati (UC) College of Medicine finds that children in East Liverpool, Ohio with higher levels of Manganese (Mn) had lower IQ scores. The research appears ...

Higher levels of fluoride in pregnant woman linked to lower intelligence in their children

September 20, 2017
Fluoride in the urine of pregnant women shows a correlation with lower measures of intelligence in their children, according to University of Toronto researchers who conducted the first study of its kind and size to examine ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.