Children with chronic exposure to high levels of fluoride in drinking water made more errors on drawing and cognitive tests, according to a new pilot study by researchers at Tulane University.
The study, which linked fluoride exposure and cognitive impairment, was published in the November-December issue of the peer-reviewed Neurotoxicology and Teratology journal.
Lead author Tewodros Godebo, Ph.D., assistant professor of environmental health sciences at Tulane University School of Public Health and Tropical Medicine, told Tulane News that the testing underlying their study “affirmed a clear association between high fluoride and cognitive impairment.”
“These results add to the growing concern about the potential neurotoxic effects of fluoride, especially during early brain development and childhood,” Godebo said. He said more epidemiological studies should be conducted to validate the findings of his team’s work.
For the study, researchers recruited 74 children ages 5-14 from demographically and ethnically similar rural Ethiopian farming communities with varying levels of natural fluoride in their community wells, ranging from 0.4 to 15.5 mg/L.
The U.S. Public Health Service recommends 0.7 milligrams per liter (mg/L) as the “optimal level” for water fluoridation and the World Health Organization recommends that fluoride levels be kept below 1.5 mg/L.
The children were tested for fluoride exposure and their cognitive performances were measured using two tests.
One test assessed the children’s abilities to draw common objects. The other used the Cambridge Neuropsychological Test Automated Battery, or CANTAB test, to assess memory and learning.
The researchers didn’t analyze IQ. Instead, they used tests designed to identify different markers of cognitive impairment and found that the higher the levels of fluoride exposure, the worse children performed on both tests and that in the CANTAB tests, the total number of errors became “markedly stronger” as the tasks became more difficult.
“This well-conducted study by a team of U.S. scientists is the latest in a long series of studies showing that fluoride is a neurotoxicant that can cause cognitive impairment in children,” Michael Connett, attorney for the plaintiffs in a lawsuit challenging the U.S. Environmental Protection Agency (EPA) to end water fluoridation in the U.S.
“At this point, it’s no longer a question of, does fluoride damage the brain? Does fluoride lower IQ?” Connett told The Defender. “It’s a question of, at what dose? How does that dose vary with innate susceptibility among the population?”
He added, “The obliviousness of public health officials to this clear and present danger is becoming intolerable.
Fluoride exposure is receiving more scrutiny from scientists and the public in part because of a lawsuit brought in 2017 by Food and Water Watch, Fluoride Action Network and others alleging water fluoridation violates the EPA’s Toxic Substances Control Act and that fluoride is neurotoxic and lowers children’s IQ.
The authors of the Tulane study called for more research on the topic, particularly for studies to establish at what level fluoride is neurotoxic, as well as the effects of low levels of fluoride in drinking water.
Higher exposure ‘consistently associated with lower IQ’
The Tulane study’s findings support similar findings released — by court order as part of the lawsuit against the EPA — by the National Toxicology Program (NTP) in March in a draft report linking prenatal and childhood fluoride exposure to reduced IQ in children.
Public health officials tried for almost a year to block its publication, documents obtained by plaintiffs through the Freedom of Information Act revealed.
The NTP — which operates under the U.S. Department of Health and Human Services National Institute of Environmental Health Sciences and analyzes environmental toxins — conducted a six-year systematic review to assess scientific studies on fluoride exposure and potential neurodevelopmental and cognitive health effects in humans.
The report, a monograph and a meta-analysis of existing studies on fluoride’s neurotoxic effects concluded that “higher fluoride exposure is consistently associated with lower IQ in children.’”
The findings from the report will inform the next phase of the trial set to begin at the end of January….