Government Report Links High Fluoride Exposure With Low IQ Among Children

Exposing children to high levels of fluoride is “consistently associated” with lower IQ, and potentially other neurodevelopmental issues, according to a report by the National Toxicology Program (NTP).

In 2016, NTP started a systematic review of scientific literature to ascertain links between fluoride and cognition. On Aug. 21, it published a report detailing its findings. A total of 72 studies reviewed in the report examined how fluoride exposure affected children’s IQ. Sixty-four of these studies found an “inverse association between estimated fluoride exposure and IQ in children,” meaning higher exposure was linked to lower IQ and vice versa.

“This review finds, with moderate confidence, that higher estimated fluoride exposures … are consistently associated with lower IQ in children,” the report stated. NTP is a unit of the U.S. Department of Health and Human Services.

NTP defined high exposure as drinking water with fluoride concentrations that exceed the 1.5 mg/L limit set by the World Health Organization.

The allowable limits in the United States are different. While the U.S. Food and Drug Administration (FDA) has set a threshold of 0.7 mg/L for fluoride presence in drinking water (including naturally occurring and added fluoride, or fluoridation), the U.S. Environmental Protection Agency has a limit of 2 mg/L.

As of April 2020, community water systems in the United States supplied water containing 1.5 mg/L or more of naturally occurring fluoride to 0.59 percent of the country’s population, which comes to approximately 1.9 million people, NTP stated. Around 1 million people were supplied water with 2 mg/L or more of naturally occurring fluoride.

“There is also some evidence that fluoride exposure is associated with other neurodevelopmental and cognitive effects in children; although, because of the heterogeneity of the outcomes, there is low confidence in the literature for these other effects,” the report stated.

The studies on children’s IQ reviewed in the report were conducted in 10 countries, including Canada and Mexico. No studies from the United States were included in the review.

Fluoride is a mineral that prevents and repairs damage to the teeth caused by bacteria. In 1945, the United States introduced a community water fluoridation program, which has been considered a successful public health measure.

However, there were concerns that children and pregnant women may ingest fluoride in excess amounts due to exposure to the mineral from a variety of sources, including water, beverages, toothpaste, and teas, the NTP said. This led the program to conduct the current study.

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