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

Nbcwashington · 🇨🇳 public China · Apr 14, 2026 · 961 words · By Erika Edwards; Kaan Ozcan; NBC News

Public Health vs. Individual Concern Scientific Research Scientific Consensus vs. Political Rhetoric Public Health Policy

headphones Listen to the eFinder podcast briefing

Generate a natural audio summary of this story

Daily briefing

What to know about Public Health vs. Individual Concern

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.

Claims checked 24

Techniques found 3

Topics 4

Coverage spectrum

Coverage gap: Low Left coverage

Left0%

Center88%

Right12%

8 sources compared across this story cluster. This is an eFinder estimate from indexed source coverage, not an editorial rating.

What happened

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.

Why it matters

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.

Common ground

and any potential impact on cognition up to age 80.

Perspective signals

The tension in the story is sharpened by Loaded Language, Glittering Generalities, Selective Omission: language that can make the dispute feel more urgent, personal, or adversarial than the underlying facts alone.

Follow-up questions

What new context would change how readers understand this Public Health vs. Individual Concern story?
What evidence would most clearly confirm or weaken the claim that 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?
How does this story connect Public Health vs. Individual Concern with Scientific Research over the next few days?

open_in_new Read the original article: https://www.nbcwashington.com/news/national-international/fluoride-drinking-wate…

psychologyPropaganda Techniques Detected

eFinder identified 3 propaganda techniques in this article. These signals explain how wording, emphasis, or missing context can shape a reader's interpretation.

warning

Loaded Language 80% confidence

Using words with strong emotional connotations to influence an audience.

Found in this article: eFinder flagged this technique because the story's framing or source language may guide readers toward a particular interpretation. Review the claim checks and evidence below to separate what is directly supported from what is implied by wording or emphasis.

Why it matters: Recognizing loaded language helps readers compare the article's framing with the underlying facts and with coverage from other sources.

warning

Glittering Generalities 70% confidence

Using vague, emotionally appealing phrases ('freedom', 'justice') without specifics.

Why it matters: Recognizing glittering generalities helps readers compare the article's framing with the underlying facts and with coverage from other sources.

warning

Selective Omission 85% confidence

Deliberately leaving out important context or facts that would change interpretation.

Why it matters: Recognizing selective omission helps readers compare the article's framing with the underlying facts and with coverage from other sources.

fact_checkClaims Checked

eFinder analyzed this article and checked 24 claims against available evidence, cross-references, web search, and Wikipedia. Here is what the fact-checking layer found.

schedule Pending 14

check_circle Corroborated 5

info Single Source 3

help Insufficient Evidence 2

check_circle

Claim 1: “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.”

CORROBORATED

The claim that opponents cite small studies from China or other countries with higher fluoride concentrations is corroborated by the provided web search results.

travel_explore

web search NEUTRAL — that fluoride allows more time for dental treatment by slowing the progression of tooth decay, and that it simplifies treatment by causing most cavities to occur in pits and fissures of teeth.[30] Oth…
https://en.wikipedia.org/wiki/Water_fluoridation

travel_explore

web search NEUTRAL — 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 …
https://www.nbcnews.com/health/kids-health/fluoride-water-ch…

travel_explore

web search NEUTRAL — The water in both countries is fluoridated. Moreover, fluoride itself may be dangerous at high levels. Excessive fluoride causes fluorosis—changes in tooth enamel that range from barely noticeable whi…
https://hsph.harvard.edu/news/fluoridated-drinking-water/

info

Claim 2: “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.”

SINGLE SOURCE

The CDC's official website confirms the optimal fluoride level is 0.7 mg/L (equivalent to 3 drops in a 55-gallon barrel), and the EPA confirms the legal limit is 4.0 mg/L.

travel_explore

web search NEUTRAL — 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 bar…
https://www.nbcnews.com/health/kids-health/fluoride-water-ch…

travel_explore

web search NEUTRAL — The recommended fluoride concentration in drinking water (also called the optimal level) is 0.7 milligrams of fluoride per liter of water.2 This is about equal to 3 drops of water in a 55-gallon barre…
https://www.cdc.gov/fluoridation/about/index.html

travel_explore

web search NEUTRAL — Primary limit: The EPA states that the maximum amount of fluoride allowable in public water sources is 4.0 mg/L. Secondary standard: This limit — 2.0 mg/L — is specifically intended to help protect yo…
https://www.culligan.com/blog/water-contaminant-spotlight-is…

schedule

Claim 3: “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.'”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 4: “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

Multiple independent web sources report that a long-term study found no association between childhood exposure to fluoridated water and IQ/brain function.

travel_explore

web search NEUTRAL — Tests of intelligence and brain function showed the same results whether or not people drank fluoridated water growing up, a highly anticipated, long-term study found.
https://www.nbcnews.com/health/kids-health/fluoride-water-ch…

travel_explore

web search NEUTRAL — Some of these children grew up drinking well water, while others drank from the community supply. Historical records of these water sources – and when fluoridation programs began – enabled a kind of n…
https://www.sciencealert.com/no-evidence-fluoride-in-drinkin…

travel_explore

web search NEUTRAL — “The study’s use of a clearly erroneous measurement of early life exposure to fluoridated water made it virtually impossible for this study to detect an association between early-life fluoride exposur…
https://www.activistpost.com/fluoride-study-claiming-no-effe…

+ 3 more evidence sources

check_circle

Claim 5: “Dr. Scott Tomar... said. 'There is no association with community water fluoridation and any measure of IQ or neurodevelopment.'”

CORROBORATED

Multiple sources attribute the quote 'There is no association with community water fluoridation and any measure of IQ or neurodevelopment' to the context of the study's findings.

travel_explore

web search NEUTRAL — Participants took IQ and cognitive tests at several points in their lives. The study found no measurable difference in intelligence or cognitive skills at any age between those who grew up drinking fl…
https://www.iheart.com/content/2026-04-13-fluoride-in-drinki…

travel_explore

web search NEUTRAL — “There is no association with community water fluoridation and any measure of IQ or neurodevelopment.”Opponents of water fluoridation have often pointed to small studies that suggested a possible link…
https://www.aol.com/articles/childhood-old-age-fluoridated-w…

travel_explore

web search NEUTRAL — "There is no association with community water fluoridation and any measure of IQ or neurodevelopment." Fear over a link to lower IQ scores has been cited by a growing number of communities across the …
https://drudge.com/news/291395/fluoride-water-has-no-effect-…

info

Claim 6: “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.”

SINGLE SOURCE

The search results provided for this claim are dictionary definitions of the word 'several' and do not provide evidence regarding state bans on fluoridation in Utah, Florida, or other states.

travel_explore

web search NEUTRAL — 5 days ago · The meaning of SEVERAL is separate or distinct from one another. How to use several in a sentence.
https://www.merriam-webster.com/dictionary/several

travel_explore

web search NEUTRAL — Nov 20, 2025 · Learn the difference between "few," "couple," and "several" in English. This complete guide explains meanings, usage, grammar rules, and examples to help you use these words correctly i…
https://englishstudyonline.org/few-vs-couple-vs-several/

travel_explore

web search NEUTRAL — SEVERAL definition: 1. some; an amount that is not exact but is fewer than many: 2. separate or different: 3. some…. Learn more.
https://dictionary.cambridge.org/dictionary/english/several

schedule

Claim 7: “Union County, North Carolina, stopped water fluoridation in 2024.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 8: “The addition of fluoride in community water systems is a 'low-cost, safe way to help protect people.'”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

info

Claim 9: “Dr. Scott Tomar, head of the department of population oral health at the University of Illinois in Chicago, called the new study 'quite significant.'”

SINGLE SOURCE

The provided web search results for this specific claim are irrelevant (listing doctors in Spokane) and do not contain the quote or mention of Dr. Scott Tomar's reaction to the study.

menu_book

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)

menu_book

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

menu_book

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

+ 3 more evidence sources

schedule

Claim 10: “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.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 11: “Since 1995, 86 Wisconsin communities have stopped adding fluoride to municipal water systems, according to the state’s Department of Natural Resources.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 12: “Water fluoridation has been heralded as one of the top public health initiatives of the last century for its ability to fight cavities.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 13: “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.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 14: “Warren said his studies shouldn’t be interpreted as the final word on the matter, and should prompt additional research.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

help

Claim 15: “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 provided in the search results to verify the specific role of Rob Warren or the 'robustness' of his study relative to others.

schedule

Claim 16: “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.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 17: “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.”

CORROBORATED

Multiple sources confirm the study was published in the Proceedings of the National Academy of Sciences (PNAS) and focused on cognition up to age 80 in the U.S.

menu_book

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…

menu_book

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

menu_book

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…

+ 6 more evidence sources

schedule

Claim 18: “Dr. Bruce Lanphear... said Warren’s latest research is 'one of the more rigorous attempts to examine fluoridation and cognition across the life course.'”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

check_circle

Claim 19: “The results contradict claims made by Health Secretary Robert F. Kennedy Jr. that fluoride is 'industrial waste' associated with IQ loss.”

CORROBORATED

Multiple sources explicitly state that the study's results contradict claims made by Robert F. Kennedy Jr. regarding fluoride as 'industrial waste' and IQ loss.

menu_book

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…

menu_book

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.

menu_book

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…

+ 6 more evidence sources

help

Claim 20: “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 provided in the search results to verify the specific details of the Wisconsin Longitudinal Study's sample size or the specific ages of testing (16, 53, 64, 72, 80).

schedule

Claim 21: “There is a limitation in the new study: The researchers didn’t measure how much fluoride individuals actually consumed, Lanphear wrote in an email.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 22: “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%.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 23: “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.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

schedule

Claim 24: “Some families who now refuse to allow their children to be treated with fluoride in dentist offices.”

PENDING

This claim was extracted as a checkable statement from the article. eFinder labels it pending based on the available evidence and source context shown below.

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.