Fluoride in water: Safe or neurotoxic?

The mineral fluoride, on the proper dose, has been proven to scale back the chance of tooth decay. Based mostly on research demonstrating this in kids consuming naturally fluoride-containing water, particular person cities within the U.S. started so as to add fluoride to faucet water starting in 1945.

The Facilities for Illness Management and Prevention and a number of knowledgeable teams endorse water fluoridation as a secure option to scale back tooth decay, together with the American Dental Affiliation, the American Academy of Household Physicians and the American Academy of Pediatrics.

Nonetheless, a Feb. 4 publish from unbiased presidential candidate Robert F. Kennedy Jr. on X, previously generally known as Twitter, made a sweeping declare about fluoride’s results on the nervous system. “As president. I’m going to order the CDC to take each step essential to take away neurotoxic fluoride from American consuming water,” the publish mentioned.

Kennedy, who has a historical past of advocating in opposition to water fluoridation, accompanied his declare about fluoride’s neurotoxicity with a hyperlink to a Law360 article about testimony in a trial that has been unfolding in a San Francisco-based federal district court docket. The case was introduced in opposition to the Environmental Safety Company by nonprofit organizations and different plaintiffs and alleges that fluoridation poses “an unreasonable danger of damage to well being” beneath a model of Poisonous Substances Management Act amended in 2016. The plaintiffs are asking the EPA to disallow including fluoride to consuming water.

Different widespread social media posts have additionally referenced the trial, claiming that “a number of research verify fluoride is a neurotoxin that violates the Poisonous Substances Management Act and reduces IQ in children.”

However the information on water fluoridation and neurotoxicity are much less clear-cut than social media posts by Kennedy or others make them out to be.

Some research — lots of them finished in areas of the world with naturally excessive ranges of fluoride of their water provides effectively above the optimally beneficial stage — recommend a attainable affiliation between higher ranges of fluoride publicity throughout being pregnant or early childhood and decreased IQ in kids. However many scientific consultants have mentioned the proof for this affiliation is weak.

The EPA has argued that there isn’t robust or constant proof fluoridation at beneficial ranges lowers IQ — according to the final sentiment held by the CDC and numerous knowledgeable teams that water fluoridation is secure.

U.S. Regulation of Fluoride in Water

On a federal stage within the U.S., the Public Well being Service first beneficial fluoridation of faucet water in 1962. Nonetheless, the determination on whether or not to add fluoride to faucet water is as much as states and municipalities. As of 2020, round 63% of People acquired fluoridated water.

Publicity to fluoride in early childhood is understood to trigger dental fluorosis, a situation most frequently characterised by gentle discoloration of the tooth. The AAP says that it’s secure to combine child formulation with fluoridated faucet water, though consuming fluoride isn’t vital for infants beneath 6 months previous and comes with a small danger of dental fluorosis.

In accordance with the CDC, consultants have concluded there isn’t an affiliation between beneficial water fluoridation and another damaging well being impacts.

Based mostly on proof of skeletal issues when individuals are uncovered to fairly excessive ranges of fluoride over time, the Environmental Safety Company has set an higher restrict of 4 mg per liter for fluoride in faucet water from public water programs. Nonetheless, the company recommends that fluoride ranges in faucet water be stored beneath 2 mg per liter to guard from dental fluorosis. The fluoride stage beneficial by the Public Well being Service to enhance dental well being is beneath these limits — at 0.7 mg per liter.

Past fluoridated water, sources of fluoride also can embody such objects as black tea or swallowed toothpaste. It’s typically solely current in very small quantities in meals, though fluoridated salt or milk fairly than fluoridated water are utilized in some non-U.S. nations.

Draft Report Wasn’t Meant to Consider Water Fluoridation Security

In a Feb. 6 publish, additionally on X, Kennedy elaborated on his fluoridation claims, referencing a draft report from the Nationwide Toxicology Program that has been a spotlight of the case in opposition to the EPA. A last model of the report has not been revealed.

“The Nationwide Toxicology Program (NTP) has declared, ‘… the information help a constant inverse affiliation between fluoride publicity and kids’s IQ,’” Kennedy’s publish mentioned, quoting from an outdated model of a meta-analysis doc related to the report and leaving out some context. A meta-analysis is a sort of examine during which researchers collect the obtainable information on a subject and mix it to try to attract a bigger conclusion.

However the NTP report was not meant to ascertain whether or not water fluoridation at typical ranges was secure and checked out fluoride publicity from any supply and at any stage. Scientists who reviewed the draft for the NTP expressed issues that the sentence Kennedy quoted didn’t make this clear.

The NTP’s studies “are utilized by different federal companies as a place to begin for additional examine to find out if there’s a danger to people, and at what publicity stage,” a spokesperson from the Nationwide Institute of Environmental Well being Sciences, which homes the NTP administratively, instructed us by way of e mail. The fluoride report “will not be a danger evaluation, and subsequently, doesn’t decide the protection of fluoride.”

Kennedy additionally claimed in his publish that the NTP report had been “hidden from the general public.” The NIEHS spokesperson instructed us that the report continues to be being revised and that publication was delayed by the NTP director, who tasked a working group with reviewing the various feedback and criticisms of the doc.

A number of teams of consultants — from each inside and outdoors the federal government — reviewed numerous drafts of the report, saying that they had issues that its conclusions weren’t correctly supported. A recurring space of concern was whether or not the authors of the NTP report had sufficiently made clear that their general conclusions on fluoride’s results on IQ may not apply to the decrease ranges of fluoride present in correctly fluoridated consuming water.

“The authors level to their inclusion of research with low fluoride ranges however present no interpretation of the proof at these ranges,” wrote the working group assembled to evaluate criticisms of the report. “Quite, the authors present a single assertion within the Summary that encompasses all research: ‘The information help a constant inverse affiliation between fluoride publicity and kids’s IQ’. This may increasingly overstate the proof supplied by research with low publicity.”

Proof on Water Fluoridation and IQ Is Restricted

David Savitz, an epidemiologist at Brown College who research the consequences of environmental exposures on reproductive well being, led a bunch of consultants that reviewed two early variations of the NTP report. This group was convened by the Nationwide Academies of Sciences, Engineering, and Medication, which gives unbiased recommendation on scientific subjects to assist the federal government set insurance policies.

Savitz testified within the trial as a witness for the EPA, zeroing in on 4 long-standing cohort research prenatal and early-life exposures to fluoride by way of numerous sources, together with fluoridated water but additionally fluoridated salt. These research evaluated fluoride exposures at ranges most related to the dialogue of water fluoridation. All of them supplied measurements of fluoride within the urine of pregnant ladies and assessed their kids utilizing cognitive checks.

“There’s not presently a constant indication of there being an affiliation current, not to mention a causal affiliation,” Savitz mentioned throughout Feb. 7 testimony, talking of IQ and fluoride publicity within the “vary of curiosity.”

The OCC and INMA research, respectively carried out in Denmark and Spain, discovered no hyperlink between elevated urinary fluoride ranges and decreased cognitive check scores. A examine in ladies in Mexico, known as ELEMENT, discovered an affiliation between elevated urinary fluoride ranges throughout being pregnant and decreased cognitive check scores in kids.

The MIREC examine, of girls in Canada, “for my part is combined,” Savitz mentioned. “Within the combination outcomes, which is I feel the place one begins, it’s very restricted in indicating a possible antagonistic impact.” But it surely did present “notable intercourse variations,” he mentioned. The examine said that elevated fluoride within the urine of pregnant ladies was related to decreased IQ scores in boys.

Different researchers have criticized among the strategies and conclusions of the MIREC examine, writing, as an illustration, that it was unclear whether or not the researchers deliberate their evaluation by intercourse previous to beginning the examine. Doing unplanned subgroup analyses can result in false-positive outcomes, the researchers wrote.

Authors of another just lately revealed meta-analyses have additionally mentioned the restricted proof on fluoride’s neurotoxicity — significantly for folks consuming water with the beneficial 0.7 mg of fluoride per liter.

A 2021 meta-analysis revealed in Scientific Studies discovered that publicity to excessive ranges of fluoride was related to decrease IQ however didn’t discover a hyperlink between publicity to low ranges of fluoride and neurological issues. The researchers outlined excessive fluoride publicity as above 2 mg per liter and low publicity as between 0.5 and 1 mg per liter. The researchers finally concluded that the standard of the proof was low general and didn’t permit them “to state that fluoride is related to neurological harm,” even at comparatively excessive doses.

One other meta-analysis, revealed in 2023 in Environmental Analysis, did conclude that research indicated fluoride publicity was related to decrease IQ in kids, probably beginning at 1 mg per liter or decrease. However the researchers additionally famous issues with the standard of the research that had been finished, discovering that these displaying the best damaging affect of fluoride have been at a excessive danger of bias. Bias happens when there may be some systematic error that leads a examine’s findings to be incorrect — equivalent to confounding components that may make a relationship appear actual when it’s not. The only examine discovered to be at low danger of bias didn’t discover a damaging impact of fluoride on IQ. 

Lastly, a examine revealed within the journal Public Well being in 2023, which solely evaluated research during which folks have been uncovered to ranges of fluoride 1.5 mg per liter and decrease, didn’t determine a relationship between fluoride ranges and IQ in numerous analyses. “These meta-analyses present that fluoride publicity related to neighborhood water fluoridation will not be related to decrease IQ scores in kids,” the researchers concluded.

The Stakes of Ending Fluoridation

Within the case in opposition to the EPA, legal professionals are not allowed to debate the advantages of water fluoridation. However amid calls to halt fluoridation, consultants instructed us, a dialogue of the potential impacts is warranted.

Lindsay McLaren, a professor of neighborhood well being sciences on the College of Calgary, checked out what occurred after the town of Calgary stopped fluoridating its water in 2011. She additionally has reviewed different analysis on the impacts of stopping fluoridation. (Calgary will resume water fluoridation later this yr.)

“Not less than within the settings which were studied, in case you stop neighborhood water fluoridation, kids’s oral well being declines,” McLaren mentioned. This significantly impacts kids who wouldn’t have good entry to dental care.

“Tooth decay will not be an innocuous downside,” McLaren mentioned. “It causes ache, it may well get contaminated, it may well make it in order that it hurts to eat, children may need bother concentrating at school.” She added that in excessive instances tooth decay can lead younger kids to want surgical procedure beneath normal anesthesia, which comes with identified dangers.

“The explanation why we put fluoride in water is as a result of it has a demonstrable constructive affect on dental well being,” Dr. Steven Novella, a neurologist at Yale Faculty of Medication, instructed us. Along with lowering cavities and bettering general dental well being, it “has downstream results as effectively as a result of unhealthy dental well being could cause normal well being issues, coronary heart illness, and many others,” he mentioned. Novella has written about anti-fluoride claims for a few years on his weblog and on the web site Science-Based mostly Medication, which he based.

Novella mentioned that whereas information point out potential neurotoxicity from fluoride at excessive doses, fluoridation at beneficial ranges “hasn’t been proven to be an precise danger in the true world.”

“You need to present that it’s inflicting an unacceptable danger that’s higher than the profit on the dose individuals are really getting uncovered to,” he mentioned, which isn’t what the information exhibits.

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