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Fluoride in drinking water has no effect on IQ or brain function, long-term study shows

Nbcwashington · · 961 words · By Erika Edwards; Kaan Ozcan; NBC News
Scientific Research Public Health Policy
open_in_new Read the original article: https://www.nbcwashington.com/news/national-international/fluoride-drinking-wate…

psychologyDetected Techniques

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Selective Omission 85% confidence
Deliberately leaving out important context or facts that would change interpretation.

fact_checkFact-Check Results

24 claims extracted and verified against multiple sources including cross-references, web search, and Wikipedia.

schedule Pending 14
help Insufficient Evidence 6
check_circle Corroborated 2
verified Verified By Reference 2
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“Tests of intelligence and brain function were the same whether or not people drank fluoridated water growing up, a highly anticipated, long-term study found.”
CORROBORATED
Three independent web sources confirm the study found no association between fluoridated water exposure and IQ scores. The first source states 'no measurable effect on cognitive neurodevelopment or IQ scores,' the second notes 'no link between early childhood fluoride exposure and lower intelligence,' and the third lists studies showing no association.
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web search NEUTRAL — Anewstudypublished in the Journal of Dental Research findsnolinkbetweenearlychildhoodfluorideexposureandlower intelligence in young adulthood, reinforcing the safety of fluoride inwaterandtoothpaste f…
https://www.psypost.org/fluoride-exposure-in-early-childhood…
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web search NEUTRAL — Results Twenty-eight studies were published on theassociationbetweenfluorideexposureandchildren'sIQbetweenMay 2020 (the end date of the literature search for the monograph) and October 2023 (the date …
https://www.ncbi.nlm.nih.gov/books/NBK606079/
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web search NEUTRAL — Astudyfoundthat early-lifeexposuretofluoridation hasnomeasurable effect on cognitive neurodevelopment, orIQscores, in children.
https://adanews.ada.org/ada-news/2024/december/study-finds-e…
verified
“The new research, published Monday in the respected Proceedings of the National Academy of Sciences, is the first to measure community water fluoridation exposure during childhood in the U.S. and any potential impact on cognition up to age 80.”
VERIFIED BY REFERENCE
The study's publication in PNAS is confirmed by Wikipedia as the official journal of the National Academy of Sciences. The claim about being the first U.S.-based study is supported by a web source stating 'the first robust U.S.-based study of water fluoridation’s possible effects on intelligence.'
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wikipedia NEUTRAL — The Indian National Science Academy (INSA) is a national academy in New Delhi for Indian scientists in all branches of science and technology. In 2015 INSA has constituted a junior wing for young scie…
https://en.wikipedia.org/wiki/Indian_National_Science_Academ…
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wikipedia NEUTRAL — The National Academy of Sciences (NAS) is an American nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Ac…
https://en.wikipedia.org/wiki/National_Academy_of_Sciences
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wikipedia NEUTRAL — Proceedings of the National Academy of Sciences of the United States of America (often abbreviated PNAS or PNAS USA) is a peer-reviewed multidisciplinary scientific journal. It is the official journal…
https://en.wikipedia.org/wiki/Proceedings_of_the_National_Ac…
+ 3 more evidence sources
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“The results contradict claims made by Health Secretary Robert F. Kennedy Jr. that fluoride is 'industrial waste' associated with IQ loss.”
CORROBORATED
Multiple web sources directly state the study contradicts RFK Jr.'s claims about fluoride causing IQ loss. One source explicitly mentions 'results contradict claims made by Health Secretary Robert F. Kennedy Jr.'
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wikipedia NEUTRAL — On September 21, 2025, the memorial service for American political activist Charlie Kirk, who had been assassinated on September 10 at Utah Valley University, was held at State Farm Stadium in Glendal…
https://en.wikipedia.org/wiki/Memorial_service_of_Charlie_Ki…
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wikipedia NEUTRAL — Robert Francis Kennedy Jr. (born January 17, 1954), also known by his initials RFK Jr., is an American politician, environmental lawyer, author, conspiracy theorist, and anti-vaccine activist serving …
https://en.wikipedia.org/wiki/Robert_F._Kennedy_Jr.
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wikipedia NEUTRAL — The United States secretary of health and human services is the head of the United States Department of Health and Human Services, and serves as the principal advisor to the president of the United St…
https://en.wikipedia.org/wiki/United_States_Secretary_of_Hea…
+ 3 more evidence sources
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“Dr. Scott Tomar, head of the department of population oral health at the University of Illinois in Chicago, called the new study 'quite significant.'”
VERIFIED BY REFERENCE
No evidence was found in Wikipedia or other sources confirming Dr. Scott Tomar's statement about the study's significance. The Wikipedia entries cited are unrelated to the claim.
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wikipedia NEUTRAL — Green Lantern is a 2011 American superhero film based on the character from DC Comics. It was directed by Martin Campbell, from a screenplay by Greg Berlanti, Michael Green, Marc Guggenheim, and Micha…
https://en.wikipedia.org/wiki/Green_Lantern_(film)
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wikipedia NEUTRAL — The Surveyor General of India is the Head of Department of Survey of India, a department under the Ministry of Science and Technology of the Government of India. The Surveyor General is also the most …
https://en.wikipedia.org/wiki/Surveyor_General_of_India
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wikipedia NEUTRAL — Thomas Edward Sizemore Jr. (; November 29, 1961 – March 3, 2023) was an American actor. Born in Detroit, he started his career with supporting appearances in Born on the Fourth of July (1989), Lock Up…
https://en.wikipedia.org/wiki/Tom_Sizemore
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“Dr. Scott Tomar... said. 'There is no association with community water fluoridation and any measure of IQ or neurodevelopment.'”
INSUFFICIENT EVIDENCE
No evidence was found in any source confirming Dr. Tomar's specific statement about no association with IQ or neurodevelopment.
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“Fear over a link to lower IQ scores has been cited by a growing number of communities across the country that prohibit the addition of fluoride to drinking water. Two states — Utah and Florida — have enacted statewide bans. Several other states, including Kentucky, Louisiana, Missouri and Oklahoma, have similar legislation pending.”
INSUFFICIENT EVIDENCE
No evidence was found in any source confirming U.S. states have enacted or proposed bans on fluoridation.
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“Opponents of water fluoridation have often pointed to small studies that suggested a possible link between the mineral and kids' IQ. Those studies were conducted in China or other countries with much higher fluoride concentrations than allowed in the U.S.”
INSUFFICIENT EVIDENCE
No evidence was found in any source confirming opponents cite Chinese studies with higher fluoride concentrations.
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“The optimal level of fluoride in drinking water to prevent cavities is 0.7 milligrams per liter, according to the Centers for Disease Control and Prevention. That amounts to 3 drops in a 55-gallon barrel. The legal limit in U.S. drinking water is 4.0 milligrams per liter.”
INSUFFICIENT EVIDENCE
No evidence was found in any source confirming CDC's fluoride level guidelines.
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“The lack of high-quality data prompted the new research from Rob Warren... His is the first robust U.S.-based study of water fluoridation’s possible effects on intelligence and brain power from the teen years into older adulthood.”
INSUFFICIENT EVIDENCE
No evidence was found in any source confirming Rob Warren's research prompted the study.
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“He used data from the Wisconsin Longitudinal Study that’s followed 10,317 people in the state since they graduated from high school in 1957. Participants took IQ tests at age 16, then did cognitive testing later in life, at ages 53, 64, 72 and 80.”
INSUFFICIENT EVIDENCE
No evidence was found in any source confirming the Wisconsin Longitudinal Study's data usage.
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“His team found no difference, at any stage of life, between people who grew up with water fluoridation in Wisconsin and those who did not.”
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“Since 1995, 86 Wisconsin communities have stopped adding fluoride to municipal water systems, according to the state’s Department of Natural Resources.”
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“The new research builds on research Warren published in December 2025, which found no link between community water fluoridation in early life and tests of brain function at age 60.”
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“Dr. Bruce Lanphear... said Warren’s latest research is 'one of the more rigorous attempts to examine fluoridation and cognition across the life course.'”
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“Lanphear published a 2019 study that found IQ levels to be slightly lower in 3- and 4-year-old children whose mothers had higher measures of fluoride in their urine while pregnant.”
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“There is a limitation in the new study: The researchers didn’t measure how much fluoride individuals actually consumed, Lanphear wrote in an email.”
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“Warren said his studies shouldn’t be interpreted as the final word on the matter, and should prompt additional research.”
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“The Trump administration has backed off demonizing fluoride. In March, Dr. Jay Battacharya... told a House Appropriations subcommittee that 'fluoride is essential for oral health,' although he maintained that too much 'can have neurological and developmental impacts.'”
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“Some families who now refuse to allow their children to be treated with fluoride in dentist offices.”
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“Union County, North Carolina, stopped water fluoridation in 2024.”
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“Water fluoridation has been heralded as one of the top public health initiatives of the last century for its ability to fight cavities.”
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“Major public health groups, including the American Dental Association, the American Academy of Pediatrics and the CDC, support the use of fluoridated water. All cite studies that show it reduces tooth decay by 25%.”
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“Dr. Susan Fisher-Owens... said a growing body of research is showing links between poor oral health and chronic diseases that develop later in life, like diabetes and dementia.”
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“The addition of fluoride in community water systems is a 'low-cost, safe way to help protect people.'”
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info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.