Last May, the National Toxicology Program (NTP), a federal research agency, was set to release its eagerly awaited report into the cognitive and neurodevelopmental impacts on humans from fluoride exposure.
The report was anticipated for several reasons, including its review of studies linking fluoridated water to cognitive harm in children. Water fluoridation is the long-established public policy of adding fluoride to drinking water to fight tooth decay. The report was also set to play a key role in an ongoing lawsuit , filed by government accountability nonprofit Food & Water Watch, to get the Environmental Protection Agency to regulate water fluoridation because of fluoride’s possible neurotoxic harm. More than two years ago, the judge put the case on hold in expectation of the NTP report’s public release.
Before the NTP could release the report, however, “They were blocked,” said Linda Birnbaum, NTP director until 2019. According to Freedom of Information Act (FOIA) records obtained by the plaintiffs and shared with Capital & Main, the U.S. Department of Health and Human Services (HHS) held back the release of the report after criticism of its findings from health and dental organizations that advocate for community water fluoridation. Those groups challenged the report’s scientific validity and expressed concern that it could jeopardize water fluoridation, which they said could especially impact the dental health of low income communities.
The report found that a link between typical levels of fluoride added to water and possible harm to brain development is unclear, with a recommendation for more studies, according to records. But the report did find a possible link to cognitive harm at approximately two times the current recommended water fluoridation level, records show. Some health experts believe this finding makes current water fluoridation levels potentially unsafe for developing fetuses and young children. Because many common foods and drinks contain fluoride, consuming them along with fluoridated water could amount to harmful exposure levels, these experts say.
Leading up to the report’s intended release, individuals from dental organizations including the American Dental Association (ADA) scrutinized the report’s scientific credibility in communications with staff from other dental groups and health agencies including the National Institutes of Health and the NTP, divisions of HHS, records show.
This January, Birnbaum issued a scathing legal declaration as part of the 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.
The NTP has announced that it will now release the report on March 15, alongside an updated version of the same document that includes the NTP’s responses to what it describes as a “significant number” of comments and criticisms received from experts at various federal health agencies.
Birnbaum, however, remains adamant that the science proves there is “no real benefit” from ingesting fluoride. “The benefit from fluoride is from topical applications,” she said.
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Water fluoridation is described as one of the 10 greatest public health achievements of the 20th century for its part in reducing tooth decay in adults and children by roughly 25%. According to the latest figures , nearly 73% of people connected with community water systems receive fluoridated water, accounting for more than 200 million people, or just under two-thirds of the overall U.S. population. Advocates argue that fluoridation is especially needed in low income communities where rates of tooth decay are generally higher than in wealthier neighborhoods.
At the same time, a growing body of research links fluoride exposure to neurotoxicological impacts in humans, including IQ loss and a higher prevalence of ADHD in children.
The NTP has been working since 2016 on its systematic review of the science into these impacts. By the time the report was set for release last May, it had already undergone more rounds of peer review than is typically the case for such a document, court records show — twice with the National Academies of Sciences, Engineering, and Medicine (NASEM), and external peer review by five experts in the field. According to Birnbaum, similar reports are typically sent out for public comment, peer reviewed by an on-site panel, then finalized by the NTP.
Despite this unusually rigorous review process, a network of health officials and influential dental groups argued that the NTP had failed to address several issues raised by the NASEM review committee. These issues include a need to consider more studies in the review, and a failure to properly account for bias among some of the studies selected. One key health official wrote that if the Centers for Disease Control and Prevention (CDC) had been given the option to clear the report, “We would have non-concurred,” records show.
Birnbaum said she strongly disagrees that the NTP had failed to address NASEM’s concerns. In her declaration, Birnbaum wrote that various sources told her the five external peer reviewers agreed with what was then the final report’s conclusions, and that “NTP’s staff and leadership considered the monograph to be complete and ready for publication by May 2022.”
The report’s critics also feared its findings could erode public trust in water fluoridation, with the head of one leading dental research organization calling it “potentially very bad fluoride news.”
In April of last year, American Fluoridation Society President Johnny Johnson wrote an open letter to “Oral Health Advocates and Public Health Leaders” warning how the NTP’s findings were already causing public health officials to second guess their stance on community water fluoridation (CWF).
“In at least one U.S. state the NTP’s draft Monograph has led to that state’s Toxicologist not being willing to support CWF as safe, when in the past that same Toxicologist was supportive. This is directly due to the NTP’s report,” Johnson wrote.
In response to questions, Johnson wrote in an email that “since the NTP report is not yet publicly available, it would be premature to comment on something that […]