NTP Report on Fluoride Neurotoxicity
“52 of 55 studies found lower IQ with higher #fluoride exposures, demonstrating remarkable consistency. Of the 19 studies rated higher quality, 18 found lowering of IQ. The meta-analysis could not detect any safe exposure.” - National Toxicology Program
The >National Toxicology Program(NTP), established in 1978, is the research arm of U.S. regulatory agencies and is best known for its reports on carcinogens. The NTP comes under the aegis of the National Institute of Environmental Health Sciences(NIEHS), an agency that has been able to perform good science amidst a battlefield of conflicting inter-agency interests. The NIEHS comes under the umbrella of the National Institutes of Health (NIH).
NTP’s Involvement in Fluoride Neurotoxicity
In 2015 the NTP solicited a request for information in the Federal Register on fluoride’s carcinogenicity, developmental neurotoxicity, and endocrine disruption. FAN submitted comments and the NTP made the decision to investigate fluoride’s neurotoxicity.
In December 2015 an “Evaluation of Fluoride Exposure and Potential for Developmental Neurobehavioral Effects” was presented by Kristina Thayer, PhD, of the Office of Health Assessment and Translation (OHAT), NIEHS, to the NTP’s Board of Scientific Counselors (BSC). Dr. Lisa Peterson, Chair of the NTP BSC, said “the priority for the project ranged from medium to high.”
In 2016 the NTP began a systematic review of fluoride’s neurotoxicity in humans (called a monograph) at the request of FAN. This was the first time that any government undertook this task. The NTP spent three years on the monograph and asked the National Academies of Sciences, Engineering and Medicine (NASEM) to peer review their work. NTP produced two draft reviews (2019 and 2020) which NASEM peer-reviewed.
The NTP draft review is the most comprehensive on fluoride’s neurotoxicity ever conducted and confirms that fluoride is “presumed to be a cognitive neurodevelopmental hazard to humans.” The rating of “presumed” is the highest confidence rating possible without doing a controlled human experiment on neurotoxicity, which would be unethical. The strongest studies in the review were conducted at fluoride exposure levels typically experienced in artificially fluoridated communities (0.7 ppm). These high quality studies consistently found strong associations between loss of IQ or other adverse developmental neurobehavioral outcomes.
Video: A Deep Dive Into The NTP Fluoride Neurotoxicity Review
"There is very strong evidence that at exposures to fluoridated water occurring right now in the United States, children are being harmed." - Chris Neurath, FAN Research Director.
For further reading, FAN has archived a detailed history of NTP’s involvement in fluoride toxicity going back to 1990.
State Of The Science
In 2017 FAN and a coalition of individuals and groups took the Environmental Protection Agency (EPA) to federal court in the TSCA Fluoride Lawsuit. The first of two trials in the fluoride lawsuit was held in June 2020. After the first trial, the Court put the case on hold to wait for the final draft of the NTP report before a decision could be made.
Inexplicably, on February 9, 2021, the NTP reversed course and stated in a private statement, not released to the press or to the public, that it would not complete its systematic review. Instead, NTP would do a “state of the science” document on fluoride’s neurotoxicity. The final report is expected to be released at the end of March 2022.
FAN learned of NTP’s private statement after lawyers representing the U.S. EPA in the TSCA Fluoride Lawsuit submitted it into the record on February 22, 2021. This submission led to a February 24, 2021, article at Inside EPA which noted that the review would not include the conclusion that fluoride is “presumed to be a cognitive neurodevelopmental hazard to humans” - thus it will have no “teeth” compared to a systematic review.
The speculation at the time was that fluoridation proponents within the NIH-NIDCR were responsible for stopping NTP’s systematic review of fluoride’s neurotoxicity. That speculation was later confirmed in a series of shocking FOIA documents gathered and produced by attorneys in the fluoride lawsuit.
Video: Emails Reveal Suppression of Government Report on Fluoride & Brain
Circling The Wagons
It wasn’t enough that dental interests were successful in getting the NTP fluoride monograph watered down to remove the hazard conclusion of “presumed” neurotoxicant. The dental lobby was dead set on stopping the monograph from EVER being published.
In a February 2022 letter to the current director of the NTP, Dr. Rick Woychik, officials from the American Dental Association (ADA) said that the ADA “is concerned about the National Toxicology Program’s forthcoming state-of-the-science report examining whether there is a causal relationship between fluoride exposure and potential neurodevelopmental and cognitive effects.”
Pressure was put on the NTP to subject their fluoride report to additional peer-reviews, beyond the already unprecedented reviews by NASEM and in contrast to previous monographs on other chemicals where there is usually just one peer-review culminating in a public vote by a panel of scientists. In May 2022, NTP Director Rick Woychik sent the document for yet another round of peer review with the agency’s Board of Scientific Counselors (BSC). The BSC made its recommendations, signing off on the document, leaving Dr. Woychik with the final decision to publish and disseminate the final version of the report.
Waiting and Waiting
That day never came. Before the NTP could release the report, “they were blocked”, said Linda Birnbaum, NTP’s Director until 2019. Emails obtained by attorneys in the Fluoride Lawsuit show the decision to put the report on hold in May 2022 came from the highest levels of the U.S. public health system - Assistant Secretary of Health, Admiral Rachel Levine. An email from the CDC dated June 3, 2022 stated, “ASH Levine has put the report on hold until further notice.”
But Freedom of Information Act Requests (FOIA) by FAN’s legal counsel discovered internal NTP emails confirming that the NTP considered the May 2022 monograph to be their final report. On April 28, 2022, the Director of the NTP’s Office of Policy, Review, and Outreach, Dr. Mary Wolfe, emailed the CDC’s Oral Health Division Director, stating that the NTP’s “analysis and conclusions are set,” and that the final report would be made public by “mid/late May” of 2022. Dr. Wolfe later notified the CDC that “we [the NTP] believe the current findings, as stated in the monograph, reflect the scope of our evaluation and the available scientific literature and no revision is needed.”
NTP’s scientific director at the time, Dr. Brian Berridge, DVM, Ph.D., wasn’t impressed with the process. FOIA emails obtained by FAN attorneys included emails from Berridge in which he wrote that there was an ongoing attempt to modify the report to satisfy interested actors.
“After 17 years in industry, I’ve seen efforts to modify messages to fit commercial interests. I wasn’t party to that there and I’m not game to do that here.” Berridge wrote.
Dr. Berridge wasn’t an author on the NTP report, but he was responsible for overseeing its production and signing off on its publication. Berridge later testified in the Fluoride Lawsuit about the peer review process of the report and why he signed off on the May 2022 version of the report as a final and complete report that was ready for publication.
Dr. Birnbaum issued a scathing legal declaration on the mishandling of the NTP report as part of the Fluoride Lawsuit, writing, “The decision to set aside the results of an external peer review process based on concerns expressed by agencies with strong policy interests on fluoride suggests the presence of political interference in what should be a strictly scientific endeavor.” Birnbaum said she issued the legal declaration in part over concerns the report might never be publicly released.
Public Release of the NTP Fluoride Report
In February 2023, as a result of months of legal motions, subpoenas, and extensive negotiations in the Fluoride Lawsuit, the National Institutes of Health (NIH) agreed to publicly release the NTP’s completed fluoride monograph, as well as comments from representatives of various agencies within HHS, and the NTP’s responses to them, after being served a court order.
The results of the report showed why the dental lobby was so intent on its suppression. The report found:
- 52 of 55 studies found lower IQ with higher fluoride exposures, demonstrating remarkable consistency.
- Of the 19 studies rated higher quality, 18 found lowering of IQ.
- The meta-analysis could not detect any safe level of fluoride exposure.
“Our meta-analysis confirms results of previous meta-analyses and extends them by including newer, more precise studies with individual-level exposure measures. The data support a consistent inverse association between fluoride exposure and children’s IQ.” – NTP
A meta-analysis is when information from all the relevant studies are combined to get a fuller and unbiased overall picture, rather than just looking at individual studies in isolation. The NTP’s meta-analysis also put the magnitude of harm into perspective:
“Research on other neurotoxicants has shown that subtle shifts in IQ at the population level can have a profound impact on the number of people who fall within the high and low ranges of the population’s IQ distribution. For example, a 5-point decrease in a population’s IQ would nearly double the number of people classified as intellectually disabled.”
The released documents include comments from NTP’s own experts confirming that the report’s conclusion - fluoride can lower IQ - applies to communities with water fluoridation programs. In numerous responses to comments by reviewers of the report, NTP made clear that they had found evidence that exposures of at least some people in areas with fluoridated water at 0.7 mg/L were associated with lower child IQ:
“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.”
The NTP also responded to commenters asking whether their meta-analysis had identified any safe exposure threshold, below which there would be no loss of IQ. The NTP responded that they found “no obvious threshold” for either total fluoride exposure or water fluoride exposure, referring to a graph in the meta-analysis (NTP’s eFigure 17 reproduced below) showing that as water fluoride concentration increased from 0.0 to 1.5 mg/L there was a steep drop in IQ of about 7 points. An external peer-reviewer commented on the size of the IQ loss: “Wow… that is substantial… that’s a big deal.”
Overall, the NTP Fluoride Neurotoxicity report provides strong evidence that fluoride is associated with a substantial loss of IQ at levels of exposure common in people drinking fluoridated water. That is the kind of data that threatens the staying power of the long-standing policy of water fluoridation in the United States.
Additional Information On Fluoride’s Neurotoxicity
Video: Linda Birnbaum’s Statement on Fluoride Neurotoxicity
Retired National Toxicology Program (NTP) Director, Linda Birnbaum, believes water fluoridation is outdated due to emerging evidence of the risk of developmental neurotoxicity and a demonstrable lack of efficacy.
“We don’t really need it added to our drinking water any more.” - Dr. Linda Birnbaum, considered one of the foremost toxicologists of our era, serving as a scientist for the U.S. federal government for 40 years.
Video: The Impact of FLUORIDE on the Developing Brain
The former director of the NIEHS, Dr. Linda Birnbaum, and top scientists in researching fluoride neurotoxicity, Dr. Bruce Lanphear, Dr. Christine Till, have released an Important Op-ed highlighting mounting evidence that fluoride may be hampering brain development and reducing kids’ IQ. The Op-ed is accompanied by a powerful short video on the impact of fluoride on brain development (below).
From The Archives
Vulnerable populations refers to specific groups and individuals who are more likely to experience detrimental effects from fluoride exposure than others in the general population.