Mild to moderate iodine deficiency during pregnancy can result in a child developing a lower IQ and diminished reading ability and comprehension later.
The findings are from a study by the University of Surrey in England, and they were published online in late May, 2013 in the medical journal The Lancet.
Study researchers found that insufficient levels of this important trace element in an expectant mother’s diet appear to put her child at risk of developing a lower IQ and poorer verbal and reading skills as a preteen. The study subjects were approximately one thousand mother-child pairs from Bristol, England, who were tracked until the children were 9.
After researchers adjusted for variables including breast-feeding history and parental education level, they found that the more iodine levels had dropped during the pregnancy, the lower the child’s intellectual performance was later on. More than two-thirds of the mothers in the study had had a mild to moderate iodine deficiency during their pregnancy.
Iodine deficiency is the most common cause of preventable brain damage in the world; according to figures from the World Health Organization, more than 30 percent of the world’s population is iodine-deficient. And this new study showed that even mild iodine deficiency in utero can impair the child’s future brain development.
Iodine deficiencies occur more often in women than in men, and they are especially common among pregnant women and older children. (Iodine deficiency cases are less common in the United States than in other countries, but they do exist.) Earlier studies have found that iodine deficiencies during pregnancy are also associated with increased incidence of miscarriages, stillbirths and birth defects.
Iodine is essential for normal metabolic cell processes, including the conversion of food into energy. Iodine also helps to maintain normal thyroid function and assists in the production of thyroid hormones. Iodine is also known to be essential for healthy brain and nerve development in the human fetus.
Medical experts urge pregnant women, and those planning to become pregnant, to ensure that they consume enough iodine in their diet. Iodine-rich foods include:
- dairy products
- fish (particularly cod and other ocean-caught fish)
- cooked eggs
- baked potatoes with skin
- navy beans
- iodized table salt (look for container label to say that salt is iodized, since not all store-bought table salts contain the added ingredient)
As for taking iodine supplements, while kelp and seaweed are sometimes touted as good dietary sources of this element, some experts caution people not to consume either, because their iodine concentrations may in fact be too high.
Two American physicians who commented on the English study urged British public policy makers to take the results of the study as a call to action, and to find ways to better insure that British citizens are informed about the importance of consuming enough iodine in their diet.
A pregnant and a nursing woman’s daily iodine requirement is double that of a woman who is not pregnant. The American doctors recommend that pregnant women take a multi-vitamin that also contains iodine.
By Eirian Hallinan