The government review comes as a federal judge is about to rule on whether water fluoridation poses a neurotoxic hazard to human health.
A landmark National Toxicology Program (NTP) report on fluoride neurotoxicity has confirmed what experts have long suggested: that fluoride is comparable to lead in its ability to lower IQ in children, according to the Fluoride Action Network.
After conducting an 8-year systematic review, which included an unprecedented number of peer reviews and attempts to suppress its release, the NTP published their long-awaited monograph. NTP authors reported that “72 studies assessed the association between fluoride exposure and IQ in children,” and 64 of those studies, amounting to 88%, found “an inverse relationship associated between estimated fluoride exposure and IQ in children.”
Of those 72 studies, the NTP reported:
“19 of those studies were considered to be high quality; of these, 18 reported an inverse association between estimated fluoride exposure and IQ in children.”
This is a 95% consistency among the highest quality studies, with the best human studies (Bashash 2017, 2018; Green 2019; Till 2020) having found neurotoxic harm to occur at current exposure levels for people living in fluoridated communities. NTP continued,
“The 18 studies, which include 3 prospective cohort studies and 15 cross-sectional studies, were conducted in 5 different countries.”
This speaks to the strength of the findings since they are consistent across diverse populations and found by different research teams from various leading public health institutions. NTP added,
“46 of the 53 low-quality studies [88%] in children also found evidence of an inverse association between estimated fluoride exposure and IQ in children.”
FAN’s Science Director, Chris Neurath says, “Although the NTP’s systematic review was not intended to define a safe lower dose, the information it compiled provides strong evidence that water fluoridation as done in the US by adding fluoride to a concentration of 0.7 milligrams per liter (mg/L) is very likely to be lowering the IQ of at least some children.”
The NTP also reviewed studies looking at effects on brain development other than IQ loss. While they found limited research, despite fluoridation being declared safe for over 75 years, the studies they did find had similarly concerning results, with NTP reporting that:
“8 of 9 high-quality studies examining other cognitive or neurodevelopmental outcomes reported associations with estimated fluoride exposure.”
A study published this past May in the Journal of the American Medical Association (Malin et. al, 2024), but not published in time to be included in this NTP report, found that in fluoridated Los Angeles, the children of mothers with higher fluoride exposures during pregnancy had double the odds of several neurobehavioral problems compared to mothers with lower exposures. Funding for the study was provided by the National Institutes of Health (NIH) and the US Environmental Protection Agency (EPA). This most recent study represents the 10th consecutive NIH-funded study in humans finding adverse effects of fluoride on children’s developing brains.
In the NTP review released today, the authors ultimately concluded,
“This review finds, with moderate confidence, that higher estimated fluoride exposures (e.g., as in approximations of exposure such as drinking water fluoride concentrations that exceed the World Health Organization Guidelines for Drinking-water Quality of 1.5 mg/L of fluoride) are consistently associated with lower IQ in children.”
To clarify at what level of exposure their review most confidently found harm, the NTP authors use the example of exposure levels commonly found in communities with 1.5 mg/L fluoride in drinking water, or greater. Proponents of fluoridation have used this language to mislead decision makers and the media about how this applies to water fluoridation in the United States, where the target concentration is 0.7mg/L.
Among pregnant women and their infants, some will drink twice as much water as the average, which will put their exposure right into the range with the strongest evidence for causing IQ loss. This is a special concern for infants fed formula made up with fluoridated water. Other major sources of fluoride include black tea for mothers and swallowed fluoride toothpaste in young children.
In 2022, the NTP’s report was blocked from public release by top officials at the U.S. Department of Health & Human Services. But under an agreement reached in an ongoing lawsuit against the EPA where a ruling is expected any day now, the report was made public. Included were comments from external peer-reviewers and internal HHS departments, along with NTP’s responses. NTP’s experts confirmed in these comments that their conclusion applies to communities with water fluoridation. When an unnamed government commenter claimed:
“The data do not support the assertion of an effect below 1.5 mg/L…all conclusory statements in this document should be explicit that any findings from the included studies only apply to water fluoride concentrations above 1.5 mg/L.”
The NTP responded:
“We do not agree with this comment…our assessment considers fluoride exposures from all sources, not just water…because fluoride is also found in certain foods, dental products, some pharmaceuticals, and other sources… Even in the optimally fluoridated cities…individual exposure levels…suggest widely varying total exposures from water combined with fluoride from other sources.”
NTP continued:
“We have no basis on which to state that our findings are not relevant to some children or pregnant people in the United States.”
“Several of the highest quality studies showing lower IQs in children were done in optimally fluoridated (0.7 mg/L) areas…many urinary fluoride measurements exceed those that would be expected from consuming water that contains fluoride at 1.5 mg/L.”
Stuart Cooper, Director of the Fluoride Action Network said, “This is a historic day for those who have warned about fluoridation’s obvious risks for more than 75 years. This report, along with the large body of published science, makes it abundantly clear that the question isn’t whether fluoridation is safe, but instead how many children have been needlessly harmed.”
Watch the former NTP director, Linda Birnbaum, PhD, blow the whistle on fluoridation in this short video clip: