A national conversation about fluoride’s health benefits exploded this fall after a federal toxicology report, court ruling and independent scientific review all called for updated risk-benefit analysis.
Fluoride, a mineral that occurs naturally in some regions, has been added to community water supplies since the mid-20th century when studies found that exposure dramatically reduced tooth decay.
The controversy, exacerbated by the description of the mineral as “industrial waste“by Robert F Kennedy Jr, Donald Trump’s choose to lead the US Department of Health, highlights some questions towns now grappling with: should the mineral’s well-established protective effects against tooth decay be prioritized so that Americans, and especially children, are not subjected to unnecessary pain and shame from an unhealthy smile? Or should the possibility of neurodevelopmental effects be prioritized even as studies continue?
“Fluoride is the perfect example of helping people without them having to do anything,” said Dr. Sreenivas Koka, the former dean of the University of Mississippi Medical Center’s school of dentistry. The state is a “dental desert”, where there is only one dentist for every one 2,120 inhabitants. “Fluoride in the water – all you have to do is drink water and you will get the benefit.”
Fluoride is added at approx 72% of community water supplies in the US, according to the Centers for Disease Control and Prevention (CDC). The CDC again endorse the practice in a scientific statement this May, saying it found no “convincing scientific evidence linking community water fluoridation to any potential adverse health effect or systemic disorder such as an increased risk of cancer, Down syndrome, heart disease, osteoporosis and bone fracture, immune disorders, low intelligence, kidney disorders, Alzheimer’s disease or allergic reactions”.
Still, controversy over water fluoridation has recently made headlines following two high-profile reports and a federal court ruling. The US National Toxicology Program causing a firestorm in August when it published a systematic review who found with “moderate confidence” that children exposed to fluoride levels twice that recommended for drinking water (1.5 mg per liter versus the recommended 0.7 mg per liter) were “consistently associated with lower IQ in children”.
Then, in October, a new Cochrane Review lowered the estimated impact of fluoride, citing the widespread use of fluoride in toothpaste that began in 1975.
“Studies conducted in 1975 or earlier have shown a clear and important effect on the prevention of tooth decay in children,” Cochrane Review researchers wrote. “However, due to the increased availability of fluoride in toothpaste since 1975, we are unlikely to see this effect in all populations today.”
The public debate comes as the National Institutes of Health (NIH), the world’s largest publicly funded research agency, is both a key funder of research that advances society’s understanding of fluoride’s non-dental health effects and an agency squarely in Trump’s shoes. cross hair.
The agency is one of the top targets for cuts and restructuring. Paradoxically, this could mean that critics like Kennedy cut fluoride research, even as the NIH funds research into potential harms. The incoming administration did not make proposals on how to improve oral health in the US.
Fluoride’s health benefits were investigated in the early 20th century, when a Colorado Springs dentist questioning why townspeople have brown, stained and decay-resistant teeth – now known as fluorosis.
Fluoride was later found to occur naturally at high levels in Colorado Springs, causing the cosmetic defects. Its decay-resistant properties were confirmed in a landmark 1945 study in Grand Rapids, Michigan, which found that children in Grand Rapids 60% less likely to develop dental caries (better known as cavities) with fluoride added to water.
By 1999, the CDC honored water fluoridation as one of public health’s greatest victories, next to seat belts and vaccination. This view was supported by a 2015 Cochrane Reviewconsidered the gold standard, which found that fluoridating water at 0.7 mg per liter to an approx 26% reduction in tooth decay, a figure still quoted by the American Dental Association (ADA) and American Academy of Pediatrics (AAP) today.
The need for preventive oral health solutions is great in the US – more than 68 million people lack of dental insurance and over one out of four adults said in a survey that they avoided the dentist because of cost.
In addition, school children lose an estimated average of 34m school hours every year due to unexpected dental visits; 2 million Americans visit the emergency room every year because of a toothache; half a million travel abroad for cheaper care and one in five American seniors is missing a single natural tooth. Lack of dental access is so common in some areas, prison doctors often have patients who have never seen one.
“One of the things I often ask young people in the juvenile prison is, ‘Do you have a doctor? Do you have a dentist?’” says Dr. Fred Rottnek, former medical director of St. Louis County Jails in Missouri and now a professor of community medicine at Saint Louis University School of Medicine. “Many of them have never reported going to the dentist.”
Modern scrutiny of fluoride’s non-dental health effects began to increase in 2015, when the National Toxicology Program (NTP) requested a systematic review on fluoride’s impact on neurodevelopment. By 2019, toxicology researcher Bruce Lanphear, of Simon Fraser University in Canada, co-authored a study that found that fluoride exposure was associated with reduced IQ, which would later be incorporated into the NTP’s systematic review.
“It gives you an indication that the science of fluoride is starting to develop – it wasn’t set in stone 70 years ago,” he said.
Lanphear, and a small group of like-minded toxicology researchers, argue that now is the time for us to “pause and have an independent scientific committee look at all this new evidence,” since “we have a lot of new science specifically about fluoride and the developing brain,” he said.
Critics were supported again when a federal court ruled in September that the Environmental Protection Agency (EPA) had to evaluate fluoride in terms of the Toxic Substances Control Act.
But doctors, dentists and mainstream professional associations from the American Dental Association to the American Academy of Pediatrics stand by recommendations for fluoridated water.
While some towns walk away of fluoride, communities like Buffalo, New Yorkrestart programs.
“It’s a shame if we don’t take advantage of what we know from science,” Koka said about the preventive effects of fluoride. “Are there challenges to doing it right? Yes, but do they have to be so strong that they try to overcome at all? It’s a tragedy.”
The CDC has also refined guidance on fluoridation in recent years. In 2015, its water fluoridation recommendations dropped to 0.7 mg per liter of water, from 0.7 to 1.0 mg per liter, depending on the climate. Later the CDC A 2019 report issued which advised parents of children under two to talk to their dentist about fluoridated toothpaste, and reminded parents of children under three to use only a “grain of rice” sized “spread”.
As critics argue that federal agencies’ recommendation remains, the US government’s National Institutes of Health (NIH) became one of the main funders of research into fluoride’s potential impact on IQ.
“Getting funding from the NIH shows they are interested in this important question,” said Christine Till, an assistant professor at York University in Canada and a co-investigator with Lanphear, whose grant study tooth dentin and neurodevelopment in Canada was funded by the NIH but turned down by the Canadian government.
Others, such as Ashley Malin, professor of epidemiology at the University of Florida, and Dana Goin, assistant professor of epidemiology at Columbia University, have also received NIH funding to research fluoride’s non-dental health effects. Malin studies fluoride’s impact on children’s sleep and Goin investigates reproductive health effects.
“There is a lot of ongoing work in this area, especially in the US,” Goin said. “Hopefully, the results of these studies will help determine whether EPA drinking water regulations and CDC recommendations for water fluoridation adequately balance the improvements in dental health from fluoridation against any potential negative effects.”
Goin’s current funding builds on her previous work, which found that water fluoridation was not associated with small-for-gestational-age or preterm births. She is now investigating whether fluoride is associated with gestational diabetes.
Malin added that it is a sign of “progress” that the studies can be discussed: “To even ask the question of whether optimally fluoridated, or the concentration in drinking water, can affect neurodevelopment was more than a decade ago quite controversial.”
