While 96% of pregnant women surveyed by researchers were aware of general nutritional recommendations for pregnant women, only 12% were aware of iodine-specific advice.
The study, published in the British Journal of Nutrition, estimated the median intake of iodine during pregnancy was 190 micrograms (ug) per day, with 74% consuming less than the World Health Organisation (WHO) recommended intake of 250ug daily.
Iodine is required for the production of thyroid hormones, which are crucial for fetal development with links between iodine deficiency and developmental impairments.
Dr Emilie Combet, who led the research at the University of Glasgow, said: “Women aren’t receiving the message about the importance of iodine in pregnancy, meaning they cannot make informed choices to ensure they get the amount they require.”
Iodine deficiency affects 1.9 billion people globally and is the most preventable cause of intellectual disability. The UK is ranked 8th in a list of iodine-deficient countries in the world. The main sources of iodine-rich foods are seafood and dairy products, and in some countries iodine-fortified salt or bread.
In the UK, the Reference Nutrient Intake (RNI) for adults is 140ug per day, with no proposed increment for pregnant and lactating women. Unborn children and young infants are entirely reliant on their mother for iodine supply, making babies and pregnant or lactating mothers the most vulnerable groups of the population.
At present there is no recommendation for routine iodine supplementation in the UK unlike folic acid and Vitamin D, or routine testing in pregnancy that would reflect iodine levels, as there is with iron.
The study surveyed 1,026 women across the UK who were pregnant or mothers of children aged up to 36 months.
Participants were asked about their awareness of nutritional guidelines and completed a food frequency questionnaire.
Knowledge of iodine-rich foods was low, with 56% unable to identify any iodine-rich food and the majority wrongfully believing dark green vegetables and table salt had high levels.
Most, 84% were unaware that iodine from diet is important for the healthy development of the unborn baby, and only 11% had heard about iodine from a healthcare professional.
Dr Combet said: “Iodine is crucial during pregnancy and the first months of life, to ensure adequate brain development, but achieving over 200ug a day of iodine through diet requires regular consumption of iodine-rich foods such as milk and sea fish. Not everyone will have the knowledge, means or opportunity to achieve this.
“There is an ongoing debate as to whether there should be some form of fortification of food with iodine. Iodine-fortified salt is common in other countries, but using salt as the delivery method has raised concerns since it is perceived to clash with public health messaging around reducing salt intake to combat high blood pressure. However, other countries have demonstrated that both measures could be held simultaneously. We need to work toward a solution.
“The most important issue to come from this study, however, was the lack of awareness of the important role iodine plays in fetal development and how to consume adequate levels of this essential mineral. This is something that needs to be addressed. Our current Yorkhill Children Charity – funded project us developing tools and resources for health care professionals and women either pregnant or planning a pregnancy.”
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