In 2019, critics of fluoride and fluoridation were thrilled to see the National Toxicology Program (NTP) draft a monograph citing some of the same safety concerns they had been raising. Citing NTP’s draft document, opponents to fluoridation declared that science was on their side. However, earlier this month, this fallacy came crashing down like a house of cards.
On February 9, a committee of the National Academies of Sciences, Engineering and Medicine (NASEM) completed its peer review of the NTP’s draft monograph. Its verdict? NTP failed to provide “a clear and convincing argument” to support its conclusion that fluoride was a neurotoxin. This was the second time in two years that the NASEM committee had rejected the NTP’s draft conclusion.
NASEM wrote that portions of the NTP document are “impressionistic and haphazard in citing various findings from studies” with no clear rationale for why some findings were reported and others were not. In addition, NASEM instructed NTP to “make it clear that the monograph cannot be used to draw any conclusions” about low fluoride exposures, “including those typically associated with drinking-water fluoridation.”
The Ongoing Fight
NASEM is arguably the most prestigious scientific body in our nation. The fact that its committee has reached this conclusion twice reveals the scientific weaknesses in the research that NTP—and fluoride opponents—have cited. Yet NASEM is not the first group of scientific experts to question the quality of studies that are weaponized by anti-fluoride activists.
In 2019, the Canadian Agency for Drugs and Technologies in Health (CADTH) evaluated one of the studies (Green et al.) cited by NTP and by many critics of fluoride. The Green paper reported a link between fluoride exposures and lower IQ scores in boys, but CADTH found this conclusion “was not supported by the data” and said the study relied on “weak” evidence.
In 2020, the Archives of Toxicology published a systematic review of research related to fluoride and neurotoxicity. Written by 31 European experts in toxicology or food safety, this review found that the evidence “does not provide sufficient arguments to raise concerns” about water fluoridation or “justify the conclusion that fluoride is a human developmental neurotoxicant” at common exposures. This review was published several months after NTP first drafted its monograph, and we have no reason to believe it was considered by NTP.
In a statement released after the review, NTP announced plans to publish the monograph as a “state of the science” document later this year. How can NTP possibly know it will be able to adequately address the long list of scientific concerns cited by NASEM within the next 10 months? Why define its timing if it is genuinely interested in addressing NASEM’s numerous concerns?
This announcement suggests a defiant attitude by the NTP committee that could put ideology ahead of science. Additionally, NTP appears poised to march ahead and publish a new version of this discredited monograph before an independent analysis is conducted of the Mexico ELEMENT and the Canadian MIREC data sets, which served as the basis for two recent studies that raised concern about maternal fluoride exposure. This analysis would seek to replicate the findings from these studies, which NTP cited in its monograph. The NASEM asked NTP to explain the rationale for omitting key results from these studies.
Years ago, statistical scientists Stanley Young and Alan Karr warned about the importance of replicating research to validate its findings. “Science works by experiments that can be repeated,” they wrote. Young and Karr tested 12 research trials and found that none of the 52 observational claims these studies made could be replicated.
The NTP committee was given ample opportunity to defend its conclusion about fluoride. It failed. Twice. The committee’s plans to publish the monograph on a predetermined schedule should worry anyone who cares about scientific rigor—and oral health.
Drinking water and toothpaste with fluoride provide important and complementary benefits. Together, the two sources offer more protection against tooth decay than using either one alone. It is a significant reason why the edentulism rate among US adults over a 50-year period fell from nearly one in five adults to only one in 20.
Despite progress, we know that people of color and those at lower income levels remain at greater risk for decay. Additionally, for children younger than age 8, fluoride helps strengthen the adult (permanent) teeth that are developing under the gums.
In this context, it would be irresponsible for NTP to proceed on autopilot and publish a document that could create unfounded fear. Discouraging people from receiving the benefits of topical fluoride and fluoridated tap water could lead to a significant spike in dental disease.
A study conducted in Alaska’s capital city showed this happened after water fluoridation ended. Dental professionals must monitor this issue and educate their patients about the strong evidence affirming the benefits and safety of fluoride.
Dr. Johnson is the cofounder and president of the American Fluoridation Society (AFS). As an advocate of community water fluoridation (CWF), he speaks to dental organizations and municipal governments to educate their members about the benefits of CWF and to combat misconceptions and misrepresentations about it. He is an active member of the ADA, the American Academy of Pediatric Dentistry, and other organizations as well as a Diplomate of the American Board of Pediatric Dentistry. He holds a BA in chemistry from the University of South Florida, a DMD from the University of Florida, and an MS in pediatric dentistry from the University of North Carolina at Chapel Hill. He can be reached at email@example.com. Learn more about the AFS at americanfluoridationsociety.org.