Armed with the knowledge that iodine is essential for fetal brain development, researchers at Surrey and Bristol universities set out to find whether “mild iodine deficiency during early pregnancy was associated with an adverse effect on child cognitive development.”

Severe iodine deficiency is considered the leading cause of preventable brain damage in the world.

Although iodine deficiency isn’t generally considered a first-world problem, increasing evidence that the U.K. may be mildly iodine deficient led the researchers to take a look at 1,000 families for their study, which was published in the Lancet.

The results were surprising, and not only in the discovery that two-thirds of the women had an iodine deficiency. Based on urine samples taken from the women when they were pregnant, they found that young children with mothers whose iodine levels were low had lower IQs and reading scores.

These children continued to have lower IQs at the age of 8 and worse reading ability by the age of 9.

Dr. Sarah Bath, one of the study’s authors, told the BBC, "We saw a three-point IQ difference between children who were born to mothers with low iodine in early pregnancy and children who were born to mothers above the cut-off."

The study concludes, “Iodine deficiency in pregnant women in the U.K. should be treated as an important public health issue that needs attention.”

The National Institutes of Health advises pregnant women to get 220 micrograms of iodine daily. The most commonly consumed sources are dairy products, fish, some fruits and vegetables, and iodized salt. Seaweed is another excellent source, but don't eat too much any source. Experts warn against getting more than 1,100 micrograms of iodine a day.

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