Two new research studies indicate that low levels of iodine in expectant mothers could result in lower IQ and literacy scores in their children. The studies were published in recent issues of the Lancet and the Journal of Clinical Endocrinology & Metabolism (JCEM).
The study appearing in the Lancet states that “while there is well-established evidence linking extreme iodine deficiency to problems with brain development, there is ‘considerably less’ research focused on the possible effects of mild to moderate deficiency on an unborn child’s cognitive development.” Led by Professor Margaret Rayman and her team of researchers, the team found “Low maternal iodine status was associated with an increased risk of suboptimum scores for verbal IQ at age 8 years, and reading accuracy, comprehension, and reading score at age 9 years, even after adjustment for many potential confounders.”
The research team analyzed the “Children of the 90s” study which followed children born to 14,000 mothers between 1990 and 1991. They discovered that “67% of mothers had levels of iodine below that recommended by the World Health Organisation.” The team reported that “children were then divided into groups according to how well they performed on IQ and reading tests at ages eight and nine, with the team finding that those children whose mothers had low iodine levels were 60% more likely to be in the bottom group.”
The second study from the JCEM found similar results, noting that iodine deficiency in expectant mothers caused lower than average literacy scores for their children in the future. Led by Dr. Kristen Hynes from the University of Tasmania, she stated that “although the participants’ diet was fortified with iodine during childhood, later supplementation was not enough to reverse the impact of the deficiency during the mother’s pregnancy.”
The study “examined standardised test scores of 228 children – finding that children whose mothers had urinary iodine concentrations of less than 150ug/L had reductions of 10% in spelling, 7.6% in grammar, and 5.7% in English-literacy performance compared with children whose mothers’ iodine levels were above the 150ug/L level.”
Hynes and her team did note that low iodine levels produced no correlation between lower scores on tests involving mathematics, and with regards to preventing iodine deficiency, she stated that “pregnant women should follow public health guidelines and take daily dietary supplements containing iodine.”
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