Experts weigh RFK Jr.’s plan to tell CDC to stop recommending fluoride
Key takeaways:
- High levels of fluoride exposure have been linked to lower IQs among children in other countries.
- The CDC’s recommended fluoride levels are less than half the levels in these studies.
HHS Secretary Robert F. Kennedy Jr. told The Associated Press that he will instruct the CDC to stop recommending fluoride in municipal water supplies.
Kennedy cannot stop communities from adding fluoride to their water, but he can tell the CDC to stop recommending it. He can also work with the Environmental Protection Agency (EPA) to change the limit of fluoride in water.
In a press release, EPA Administrator Lee Zeldin announced that the agency will conduct a thorough review of new data on the issue.
“Secretary Kennedy has long been at the forefront of this issue,” Zeldin said in the release. “His advocacy will be instrumental in our decision to review fluoride exposure risks, and we are committed to working alongside him, utilizing sound science as we advance our mission of protecting human health and environment.”
To get some perspective on the issue, we spoke with Ashley J. Malin, PhD, assistant professor of epidemiology at the University of Florida, who has studied neurological and other health effects of fluoride exposure, and Brett D. Kessler, DDS, president of the American Dental Association.
Fluoridation in the United States
Municipalities in the U.S. began adding fluoride to local water supplies in 1945, and the federal government has recommended its use since 1962, according to the CDC. By 1969, nearly half of Americans had access to fluoridated tap water, and by 2012, 74.6% of public water systems added fluoride.
According to Kessler, the EPA’s Maximum Contaminant Level (MCL) is 4 mg/L, although it also has a secondary limit of 2 mg/L to prevent tooth discoloration. Kessler said water systems are legally required to inform customers if the concentration exceeds 2 mg/L.
Although the enforceable limit is 4 mg/L, the CDC recommends a concentration of 0.7 mg/L. WHO recommends a maximum of 1.5 mg/L.
“The only proven risk — and it is a very low risk — for fluoride at the level we fluoridate in the U.S. is mild to minimal fluorosis,” Kessler said.
According to the CDC, dental fluorosis causes white spots on tooth enamel in young children but does not cause pain or affect tooth function.
“There are areas in the U.S. that have high natural levels of fluoride, and in those areas, you can see moderate to severe dental fluorosis,” Kessler said. “Some countries in Africa, the Middle East and Asia also have very high natural levels of fluoride in their water, and in those countries, you can see skeletal fluorosis.”
Skeletal fluorosis from chronic exposure to high fluoride levels causes weakness in bones and joints, and it can lead to osteoporosis and arthritis, according to the Cleveland Clinic. It is rare in the U.S. In India, where the risk for fluorosis is higher, the average fluoride level in groundwater is 2.37 mg/L.
According to a report from the National Toxicology Program, an estimated 1.9 million people in the U.S. live in communities with levels above 1.5 mg/L, and 1 million people live in areas with fluoride levels above 2 mg/L.
Links to neurological issues
According to a study by Malin and colleagues that was published last summer, children whose mothers were exposed to higher levels of fluoride during pregnancy were more likely to have neurobehavioral issues by their third birthday. Specifically, the researchers reported that every 0.68 mg/L increase in fluoride levels doubled the odds that babies would develop neurobehavioral symptoms.
Additionally, a systematic review published in August 2024 and a meta-analysis that came out in January 2025 demonstrated with moderate confidence that children in communities with fluoride levels above 1.5 mg/L had lower IQ scores compared with children in communities with lower fluoride levels. However, none of the dozens of studies included in the analysis were conducted in the U.S., and the level of fluoridation associated with lower IQs was more than double the level recommended for the U.S. drinking supply, the authors reported.
The analysis concluded that every 1 mg/L more fluoride in mothers’ and children’s urine led to a 1.63-point reduction in IQ.
“It is understandable that Secretary Kennedy and other policymakers have concerns about the link between fluoride exposure and IQ in children, given the current state of science,” Malin said.
But Kessler noted that three-quarters of the studies in the review were considered low quality with a high risk of bias.
“Even if [it] had been a great study, it would still indicate that lowering the maximum contaminant level to 1.5 mg/L would be preferable to eliminating fluoride altogether, and we still fluoridate at less than half that level,” he said.
Malin noted that 18 of the 19 high-quality studies in the analysis found that fluoride was associated with lower child IQ.
Last September, shortly after the results were published, a federal judge ordered the EPA to further regulate fluoride levels in drinking water, arguing that there was insufficient margin between the recommended level (0.7 mg/L) and the level that was associated with lower IQs (1.5 mg/L).
Benefits vs. risks
Malin said that policymakers will need to balance the benefits that fluoride provides to teeth with the risk to children’s brain development.
“Removing added fluoride from water supplies would protect the developing child brain from unreasonable risk,” she said.
Some lawmakers have decided that the benefits are not worth the risk.
Utah Governor Spencer Cox signed a bill in March that will prohibit municipalities from adding fluoride to local water supplies. The Associated Press reported that similar bills have been introduced in Florida, Ohio and South Carolina. However, legislators in New Hampshire, North Dakota and Tennessee struck down legislation introduced in those states.
Proponents of the bill in Utah argued that topical fluoride treatments — including toothpaste, oral rinses and fluoride tablets — have a greater impact on dental health than fluoridated water, but Kessler said one intervention cannot replace another.
He said toothpaste with a high fluoride concentration gives teeth a “a boost” in the morning and evening, but fluoridated water helps repair damage to the enamel from eating and drinking throughout the day.
“We often use the analogy of seatbelts and airbags,” Kessler said. “We would not get rid of one because ... they work together to add additional safety.”
If fluoride is removed from public water supplies, Kessler said children from low-income families will be affected most. According to Kessler, cavity rates are 25% higher among children from low-income families, compared with children who are not from low-income families.
“When community water fluoridation is eliminated, children in low-income families and people with little access to care will be the ones that suffer the most,” Kessler said.
What could happen after fluoride is removed? The city of Calgary in Alberta, Canada, could serve as an example.
In 2011, Calgary’s City Council voted to remove fluoride from the local water supply.
Eight years later, researchers reported that a significantly larger proportion of children in Calgary had dental caries compared with children living in Edmonton — another city in Alberta that still had fluoridated water.
Additionally, a retrospective study found that more children in Calgary needed general anesthesia to treat dental caries after fluoride was removed from city water vs. before the removal.
During Canada’s 2021 general election, 62% of Calgary residents voted to reinstate fluoridation in the city.
Still, recent evidence suggests that fluoridated water may have a limited effect on dental caries. A recent Cochrane Review of 21 studies conducted after 1975 found low certainty evidence that fluoride initiation reduced dental caries in communities by 4 percentage points. The researchers said the evidence included “the possibility of benefit or no benefit.”
Both Malin and Kessler argued that more research is needed.
“EPA researchers should consider the current state of the science on fluoride and neurodevelopment, as there have been major milestones in this research area during the last 10 years,” Malin said.
She called for more U.S.-based studies on how fluoride impacts bone health, thyroid function and neurocognitive function among adults.
Kessler said EPA researchers should look at studies from countries that fluoridate at similar levels to the U.S.
“Large, long-term studies from other countries like Australia and New Zealand do not show the differences that the India, China and Pakistan studies show,” he said.
For more information:
Ashley J. Malin, PhD, can be reached at editor@healio.com.
Brett D. Kessler, DDS, can be reached at kesslerb@ada.org.
References:
- Brown M, et al. Utah bans fluoride in public drinking water, a first in the US. https://apnews.com/article/utah-fluoride-ban-43f67153beb3e06ada9d782655fb15de. Published March 28, 2025. Accessed April 16, 2025.
- CDC. About dental fluorosis. https://www.cdc.gov/oral-health/about/about-dental-fluorosis.html. Published May 15, 2024. Accessed April 16, 2025.
- CDC. Timeline for community water fluoridation. https://www.cdc.gov/fluoridation/timeline-for-community-water-fluoridation/index.html. Updated May 15, 2024. Accessed April 16, 2025.
- Cleveland Clinic. Fluorosis. https://my.clevelandclinic.org/health/diseases/23227-fluorosis. Updated Oct. 14, 2024. Accessed April 16, 2025.
- Fluoride in Calgary’s water. https://www.calgary.ca/water/drinking-water/fluoride.html. Accessed April 16, 2025.
- Iheozor-Ejiofor Z, et al. Cochrane Database Syst Rev. 2024;doi:10.1002/14651858.pub3.
- Malin AJ, et al. JAMA Netw Open. 2024;doi:10.1001/jamanetworkopen.2024.11987.
- McLaren L, et al. Community Dent Oral Epidemiol. 2021;doi:10.1111/dcoe.12685.
- Schoenbaum H, et al. RFK Jr. says he plans to tell CDC to stop recommending fluoride in drinking water. https://apnews.com/article/fluoride-cdc-epa-6f4dbc64b5dc511f712a82cd2d252d76. Published April 7, 2025. Accessed April 16, 2025.
- Stobbe M. Fluoride in drinking water poses enough risk to merit new EPA action, judge says. https://apnews.com/article/fluoride-ruling-drinking-water-ccdfa11138600ab0838ebf979cbaead2. Published Sept. 25, 2024. Accessed April 16, 2025.
- Taylor KW, et al. JAMA Pediatr. 2025;doi:10.1001/jamapediatrics.2024.5542.
- U.S. Environmental Protection Agency. EPA will expeditiously review new science on fluoride in drinking water. https://www.epa.gov/newsreleases/epa-will-expeditiously-review-new-science-fluoride-drinking-water. Published April 7, 2025. Accessed April 16, 2025.
- U.S. National Toxicology Program. Fluoride exposure: Neurodevelopment and cognition. https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/completed/fluoride. Updated Jan. 6, 2025. Accessed April 16, 2025.
- U.S. National Toxicology Program. NTP monograph on the state of the science concerning fluoride exposure and neurodevelopment and cognition: A Systematic Review. https://doi.org/10.22427/NTP-MGRAPH-8. Published Aug. 21, 2024. Accessed April 16, 2025.
- Yazdanbakhsh E, et al. Can J Public Health. 2024;doi:10.17269/s41997-024-00858-w.
Perspective
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Dental decay is the most common chronic disease of childhood and a leading chronic disease of adults. Untreated dental decay prevents children from eating, sleeping, playing, concentrating and learning — thus delaying brain development. Dental decay can cause systemic infection that can be life threatening. Major chronic diseases such as Alzheimer’s disease, obesity, cardiovascular disease and rheumatoid arthritis are associated with missing teeth and edentulism. Dental decay is reduced by approximately 25% with water fluoridation, which is measured with 80 years of evidence of efficacy and safety.
Yet fluoridation has always been under continual attack since it commenced in 1945. Formerly alleged to be a ‘communist plot,’ it is now falsely alleged to cause harm to the brain.
The claim is propounded by researchers who do not measure fluoride exposure accurately. Spot urine has been demonstrated for some time to be an invalid measure of fluoride exposure. WHO’s technical guidelines for measuring fluoride in humans were published in 2014. The guidelines make clear that spot urine cannot be used to measure the fluoride exposure of an individual. The guidelines stipulate that a 24-hour urine collection also fails to measure individual fluoride exposure. In an article published last year in Community Dentistry and Oral Epidemiology, we explained how the Canadian MIREC fluoride-IQ studies are false.
Why would researchers use an invalid measure of fluoride exposure and then make strong claims that, for example, pregnant women should avoid drinking tap water?
Moreover, why would researchers who propound the false claim not cite the well-designed studies that demonstrate that there is no link between fluoridation and harm to the brain?
One cannot know another’s motives. The effect, however, is that many U.S. cities are losing their water fluoridation based on invalid studies. Many people will thereby be harmed.
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Professor of pediatrics and community health sciences
Cumming School of Medicine, University of Calgary
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