Robert F. Kennedy Jr.’s skepticism about fluoride has become a focal point in the debate about whether he’s suitable to run the nation’s health department.
His pledge that the Trump administration would “advise all U.S. systems to remove fluoride from public water” has sparked outcry among dentists and some public health experts who say that fluoridated water is safe and essential for protecting oral health in children.
But other medical experts have raised concerns about the potential negative health effects of high levels of fluoride, particularly for fetuses and young children.
This isn’t the first time concerns about fluoride have cropped up: Opposition to fluoride dates back to the 1940s and ’50s. At that time, some people felt that more studies were needed to establish the safety of water fluoridation. In addition, unfounded conspiracy theories — like that fluoridation was a Communist plot to poison Americans — began to spread. Skepticism about fluoride became so associated with fringe worldviews that it became a kind of punchline.
But the research shows a more nuanced picture of fluoride’s benefits and risks. Here’s what to know.
How important is fluoride for our health?
The greatest benefit of fluoride is that it improves children’s oral health. The mineral prevents cavities by making teeth stronger and may also reduce the amount of acid that bacteria on the teeth produce, which can damage enamel and make them more susceptible to cavities.
Cavities in children can lead to infection and tooth loss, which can make it harder for them to eat or even speak, said Dr. Scott Tomar, a public health dentist and oral epidemiologist at the University of Illinois Chicago College of Dentistry. Dental pain and cavity-related infections can also keep kids out of school, and are linked to poor academic performance.
The benefits of fluoride have been clear for about a century, ever since researchers found that children who drank water that naturally contained it had fewer cavities. Grand Rapids, Mich., became the first city in the world to begin intentionally fluoridating its water in 1945, according to the National Institutes of Health. A decade later, the rate of tooth decay in the city’s children had dropped by more than 60 percent.
There is less research in adults, but the studies that do exist suggest that fluoridation reduces adult cavities too, Dr. Tomar said. One review of the research found that water fluoridation was associated with a 27 percent decline in cavities among adults. Experts said a reduction in cavities could in turn reduce the risk for chronic conditions linked to oral health, such as heart disease.
“We continue to learn that oral health is strongly associated with other systemic health problems,” said Dr. F. Perry Wilson, a physician and chronic disease epidemiologist at the Yale School of Medicine.
Why are people worried about water fluoridation?
Although fluoride provides clear oral health benefits, it also comes with potential risks, as many public health interventions do. It is well-documented that above certain amounts, fluoride can lead to bone disease and tooth staining. But the most talked-about concern in the United States is that fluoride might have cognitive effects in young children — though the science on that is less settled.
These concerns hinge on the amount of fluoride you consume. To understand them, it’s essential to first understand how much fluoride is in our water. The legal fluoride limit for drinking water in the U.S. is four milligrams per liter. The Environmental Protection Agency has said that cutoff protects against a severe bone disease that can occur with chronic exposure to levels more than twice that high.
The lowest recommended limit — one that’s not legally mandated, but is nonetheless thought to maximize fluoride’s benefits and minimize risks — is 0.7 milligrams per liter, set by the U.S Public Health Service.
Most U.S. water supplies fall within the recommended limit of 0.7 milligrams per liter. But not all of them do: An estimated 15 percent of public water systems, serving more than 20 million Americans, had average fluoride concentrations that exceeded that level, per one study. Nearly 5 percent of systems had fluoride levels more than twice that high, and 0.3 percent had more than four milligrams per liter.
Naturally occurring fluoride seems almost entirely to blame for these especially high levels. It can end up in water systems through runoff from rocks and soil, said Anne Nigra, an environmental health scientist who studies U.S. drinking water at the Mailman School of Public Health at Columbia University and who was a co-author of that study.
Private wells, which serve about 15 percent of the U.S. population, are not as closely monitored. But a 2020 study found that nearly 11 percent had fluoride levels exceeding 0.7 milligrams per liter.
It’s those higher levels that have caused concern: Some studies have found a link between exposure to fluoride above 0.7 milligrams per liter during pregnancy and slightly lower IQ scores in children.
In a highly publicized 2019 paper, researchers compared the IQ test scores of 512 young children in Canada to their mother’s urinary fluoride levels during pregnancy, a proxy for fluoride intake. For every increase of one milligram per liter in urinary fluoride, they saw a 4.49 point drop in IQ in boys. The researchers found no relationship with IQ in girls.
The amount of fluoride the women had consumed “is well within the normal range of what you would find in populations living in fluoridated communities,” noted Christine Till, one of the authors of that study and a clinical neuropsychologist at York University in Toronto.
Other studies have also found links between fluoride and cognition. In August, the National Toxicology Program, an arm of the federal health department, released a report reviewing the evidence to date. That report concluded that exposure to drinking water at 1.5 milligrams per liter or higher is “consistently associated” with lower IQ in children. (The authors said more studies are needed on lower levels of exposure.)
Other research hasn’t found this connection, however. For example, one 2023 study of 2,682 adolescents in Australia found no differences in behavioral development or executive functioning between children who had spent the first five years of their lives drinking fluoridated water and those who hadn’t. And a 2019 studyin Mexico found no relationship between children’s intellectual ability and fluoride levels in their drinking water or their urine.
No large, longitudinal studies on the topic have been conducted in the United States.
The contradictory results, along with the limitations of the existing studies, have fueled a contentious — and still ongoing — debate among experts about the potential risks.
What does that mean for pregnant women and children?
It’s a tricky question to answer, since experts don’t all agree how worried we should be.
Some do not think that the findings so far are enough to suggest that fluoride carries risks to children, because they don’t show cause and effect. While scientists try to control for other factors that might be associated with fluoride intake and IQ, such as socioeconomic status, these controls are never perfect, Dr. Wilson, of Yale, said. He said that the potential for harm “is something that we should look into, but the evidence base is really weak.”
Dr. Tomar agreed, saying that “the overwhelming body of evidence suggests that there is no harm to either the mother or the fetus from drinking fluoridated water at the levels of fluoride that are in the U.S.”
But other researchers, including Dr. Till, say that there’s enough evidence at this point to suggest that pregnant women should try to limit their fluoride intake. (More on how to do that below.)
Dr. Till also suggested that parents may want to use fluoride-free water to mix infant formula. Babies drinking formula mixed with fluoridated water are exposed to a far higher amount than babies who are breastfed. The American Dental Association maintains that the use of fluoridated water in infant formula is safe, but says parents who want to minimize the risk of mild dental fluorosis should mix formula with fluoride-free water.
Fluoride exposure isn’t just about the water you drink. For instance, young children sometimes ingest too much fluoride if they swallow their toothpaste, said Tewodros Godebo, a scientist at Tulane University who studies fluoride. Other common dental sources of fluoride are rinses, supplements and professionally applied varnishes.
Black, green, oolong and white teas can also be naturally high in fluoride, Dr. Godebo said. He said that pregnant women may want to limit their consumption of tea and fluoridated water, “just to be on the safe side.” Soft drinks and juice can contain fluoride, too.
If you want to reduce levels of fluoride in your water, Dr. Nigra recommended searching this National Sanitation Foundation database, which lists reverse osmosis water treatment systems that have been certified to reduce fluoride levels.
How do I know how much is in my tap water?
Contact your local water utility, or search the C.D.C.’s My Water’s Fluoride database or the Environmental Working Group’s Tap Water database. (These are not always up-to-date.) If your water comes from a private well, contact your local health department to find out how to have it tested.
Every year, water providers are also required to provide consumers with a drinking water report called a Consumer Confidence Report, which would contain information on excessive fluoride.
What if my tap water isn’t fluoridated?
Dental experts recommend fluoride toothpaste whether your water is fluoridated or not. The C.D.C. says toothpaste and fluoridated water work together to protect your teeth, with water maintaining low levels in the mouth all day, and toothpaste providing a higher concentration at important times, like before bed.
Even if your home drinking water is not fluoridated, you may still be consuming fluoridated water from other sources, such as your workplace or school.
Still, if you’re concerned about your oral health, talk to your dentist, who may recommend that you use other fluoride products, Dr. Tomar said.
Could the Trump administration end water fluoridation nationally?
The decision to add fluoride to water is typically made at the local level, Dr. Tomar said, so it’s unclear what effect a federal action would have. Although some states mandate fluoridation, not all local municipalities within those states comply, he said.
It’s possible there could be federal action on fluoride outside of Mr. Kennedy’s efforts: In September, a federal judge in California ruled that, given the potential risks, the E.P.A. must take further regulatory action on fluoride. The judge did not dictate, however, what that move must be.
Some critics of fluoridation point to other countries’ decisions to not fluoridate water. But these do not always make good comparison points, because some countries provide it to their populations in other ways. An estimated 300 million peopleworldwide consume fluoridated salt, for example, and another 1.5 million children globally consume fluoridated milk.
What would getting rid of fluoride in water mean for our health in the United States?
No one knows what exactly would happen, but experts generally agree it would be harmful to oral health, particularly in children. One 2018 study found that U.S. children living in communities without access to fluoridated water had 39 percent more cavities in their baby teeth, and 16 percent more cavities in their permanent teeth, than children in communities where most people had access to fluoridated water.
And, as experts have said, those cavities could have effects that extend beyond oral health.
Dr. Tomar, who runs school-based dental programs, said he sees many children without access to good dental care, or even the opportunity for good oral hygiene. “Many kids tell us that they don’t even have their own toothbrush,” he said. While ending widespread water fluoridation could have broad effects on our oral health nationwide, he said, it is likely to be most damaging to the health of low-income Americans.
Original article online at: https://www.nytimes.com/2024/12/12/well/fluoride-water-health-pregnancy-children.html