Low iodine levels during pregnancy could have an adverse impact on the mental development of the child, a new study has found.
The findings suggest that iodine deficiency among pregnant women is a public health issue that needs to be addressed, according to the scientists behind the research, which was published in the Lancet.
There is well-established evidence linking extreme iodine deficiency to problems with brain development, but considerably less research has focused on the possible effects of mild to moderate deficiency on an unborn child’s cognitive development.
Pregnant women are among certain UK population groups recently identified as showing mild-to-moderate iodine deficiency, which led to this latest study.
The main dietary sources of iodine are seafood and dairy products. The chemical plays a crucial role in producing the hormones made by the thyroid gland, which have a direct effect on foetal brain development.
Professor Margaret Rayman, of the University of Surrey, led a team of researchers from Surrey and Bristol universities using data from a long-term health project known as ‘Children of the 90s’.
The data covers more than 14,000 mothers who enrolled when pregnant in 1991 and 1992, with the health and development of their children tracked in great detail.
Children born to women in the iodine-deficient group were significantly more likely to have low scores of verbal IQ, reading accuracy and reading comprehension, the scientists said.
They also reported that the lower the mother’s concentration of iodine, the lower their child’s average scores for IQ and reading ability.
“Our results clearly show the importance of adequate iodine status during early pregnancy, and emphasise the risk that iodine deficiency can pose to the developing infant, even in a country classified as only mildly iodine deficient,” said Professor Rayman.
Co-author Professor Jean Golding OBE said the findings provide “further strong evidence” of the need to eat iodine-rich foods such as fish during pregnancy.
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