A new study suggests that high amounts of a chemical commonly found in nearly everything we consume may be limiting the intelligence of children before they are even born. The chemical is perchlorate, found in many foods and drinking water supplies, and the detailed study revealed women with higher amounts of it in their body gave birth to children with below-average IQs.

Researchers from Boston University School of Medicine and Cardiff University combined efforts to study how high levels of perchlorate in mothers affect their offspring, according to a recent press release. Perchlorate is both a naturally occurring and man-made chemical used in the production of rocket fuel, missiles, fireworks, flares, and explosives. The contaminant is released into the environment primarily during military operations and programs, seeps into the ground water and soil, where it eventually finds its way into our food chain and drinking water. It is reported that there are traces of this contaminant in the bloodstreams of nearly every human on the planet.

Perchlorate’s effect on the thyroid is sometimes extreme. High exposure to the chemical affects the body’s ability to absorb iodine, the building block of thyroid hormones. Low iodine levels can cause a condition called hypothyroidism. In their study, researchers followed 487 mother-child pairs from women with underactive thyroid glands. In the 50 women with the highest levels of perchlorate in their body, their offspring had below-average IQ levels when compared to other children, according to the press release.

Although this is the first study to find such specific effects of perchlorate contamination, the chemical has been linked to health risks by the Centers for Disease Control and Prevention for some time now. Still, the chemical’s effects are not as widely known to the public, despite its clear danger. "The reason people really care about perchlorate is because it is ubiquitous. It's everywhere," lead researcher of the study, Elizabeth Pearce, explained in the press release. 

Pearce was not exaggerating when she described the chemical as “ubiquitous." The Agency for Toxic Substances & Disease Registry reports that the contaminant is found in food, milk, and plants, especially leafy green vegetables. In one investigation by the FDA, 74 percent of all food tested contained some levels of perchlorate. The ATSDR advises that you drink bottled water if your area has been reported to have perchlorate in the drinking water. Other simple tasks such as washing your hands before putting them in your mouth, preventing children from eating dirt, and washing as soon as you get home if you work in a factory, are advised as measures to reduce perchlorate exposure.

Source: Pearce EN, Taylor PN, Okosieme OE, et al. Maternal perchlorate levels in women with borderline thyroid function during pregnancy and the cognitive development of their offspring; Data from the Controlled Antenatal Thyroid Study. The Journal of Clinical Endocrinology & Metabolism. 2014.