Moms With Iodine Deficiency Have Babies With Lower IQs

New research shows women with even a mild-to-moderate iodine deficiency risk having children with lower IQs and reading ability.

Proper nutrition is important for expecting mothers. Chief amongst important nutrients is iodine. Iodine is critical for metabolism, and specifically in neurological development. Because of its neurological role, iodine is essential for the development of the fetal brain.

In a recent study in The Lancet, researchers wanted to find two primary pieces of information regarding iodine. First, they wanted to find the extent to which iodine deficiency during pregnancy affects the IQs of the children after birth. Second, it is known that iodine deficiency is a risk in developing countries, but researchers wanted to know if it was also a threat to already developed countries.

The researchers used stored urine samples from 1,040 pregnant women to determine their iodine levels. They then examined IQ tests done on the children at eight years of age and reading ability tests done at the age of nine. Once they had the data in hand all they had to do was compare the iodine status of a pregnant mother with the testing done on the children.

There was a very clear link. Women with only a mild-to-moderate iodine deficiency were more like to have children in the lowest 25% of IQ and reading ability. Sure enough iodine status affected their children for many years to come. The researchers were also sensitive to confounding factors, such as economic level and so forth, which they statistically factored out.

While iodine deficiency in developing countries is a serious nutritional problem, it was thought that this was not an issue for the rest of the world. Think again. This study was performed in the United Kingdom, which was thought to be a country with no iodine issues at all. However, the average iodine status of over one thousand women studied was considered mild-to-moderate deficiency. And no, they didn’t choose these women in any special way. They merely had the funding to analyze that many women out of about 14,000 total in the larger study. This means that expecting mothers everywhere need to pay attention to this important facet of prenatal nutrition.

Getting iodine is easy enough if you focus on healthy eating. Because iodine isn’t stored in the body, it is important you get enough of it every day. Many seafoods are rich in iodine, especially sea vegetables like kelp, as are dairy foods, eggs, turkey, and potatoes. Also many table salts are fortified with iodine as a means of curbing iodine deficiency. They are plainly stated on the label as “iodized salt.”

Iodine is important for everyone, including athletes, to maintain adequate metabolism and nerve health, but for expecting mothers this study shows that it might be of utmost importance. The good news is it’s not hard to get what you need by getting your nutrition dialed in. While iodine is a nutrient you need to have a part of your daily nutritional focus, it’s easy to find.


1. Sarah C Bath, et. al., “Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC),” The Lancet, 2013

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