Fighting for the F Word: Defending Fluoride Against Fear and Faulty Science

One of Our Greatest Public Health Achievements Keeps Taking Punches

I spent the morning discussing fluoride on NYPR's The Brian Lehrer Show, and it's clear the "F word" is on everyone's tongue right now. The conversation was spirited (but respectful) and highlighted how deeply misconceptions about fluoride have permeated public discourse. Let’s discuss…

Fluoride Under Fire

The FDA's announcement about removing prescription fluoride supplements from the market came just hours after my radio interview wrapped up, almost as if timed to continue the never-ending attacks against fluoride, a naturally occurring mineral. This decision, made under an administration where HHS is led by a long-time fluoride skeptic, exemplifies how politics can sometimes influence evidence in public health.

The FDA's tweet stated that "Ingested fluoride has been shown to alter the gut microbiome" and suggested associations with "thyroid disorders, weight gain, and possibly decreased IQ." These claims lack critical context about dose levels and clinical significance. The studies showing microbiome alterations typically involve fluoride levels far higher than those used in community water fluoridation and fail to demonstrate any clinical consequences from these changes. And as for the IQ link… we have discussed the many flaws with the research used to support the claim that fluoride impacts IQ, including the recent NTP report that’s gone viral. Search our Substacks by keyword or start here for a refresher.

This is the crucial distinction that keeps getting lost in these debates: HIGH levels of fluoride are concerning—but that is totally irrelevant to the low, carefully optimized levels in our community water fluoridation programs (0. 7 mg/L). If people were genuinely concerned about fluoride exposure, they should focus on removing fluoride in areas where natural levels are excessive (above 1.5 mg/L), not attacking evidence-based public health measures.

The JAMA Study Misconception

During the radio discussion, a fellow guest repeatedly referenced a recent JAMA study linking fluoride to decreased intelligence. This study has been thoroughly dissected by many scientists including Drs. David Robert Grimes, Matthew Jané, and James Heathers, who found it "irreparably flawed" and recommended retraction. Their forensic meta-science review revealed "unjustified methodological and statistical errors which invalidate their conclusion," as well as reliance on non-MEDLINE indexed publications with anti-fluoridation editorial stances.

This mirrors the flaws in the 2019 Canadian study, which was recently debunked in a March 2024 peer-reviewed analysis published in Community Dentistry and Oral Epidemiology. The authors of this critique, Guichon et al., concluded that "MIREC's fluoride and IQ measurements are invalid and therefore cannot support the claim that CWF is associated with IQ decline in children." The measurements used for both fluoride exposure (spot urine tests) and IQ were deemed unreliable, with different testers used in different cities without proper validation.

In plain speak: the research being cited in support of fluoride’s removal from community water crumbles under scrutiny— and is not all that convincing.

Pregnancy and Fluoride: Setting the Record Straight

Claims about fluoride risks during pregnancy warrant special attention. As a mama bear myself (one who remembers vividly being very mindful of anything I put in my body while pregnant), I remain deeply unconvinced by these data for several methodological reasons:

1. No professional recommendations against fluoridated water: There are no recommendations from any major health organization for pregnant women to avoid fluoridated water. The American Academy of Pediatrics explicitly states there is "no reason for pregnant people to drink bottled water unless they are concerned about other contaminants."

2. Serious measurement issues: Studies linking maternal fluoride exposure to neurodevelopmental effects have significant methodological flaws, including unreliable spot urine samples, failure to adjust for other neurotoxic exposures, and reliance on parent self-reporting.

3. Contradictory and null findings: Multiple studies have produced contradictory results. One replication study in Spain showed the opposite effect—fluoride led to a slight increase in boys' cognition. Long-term cohort studies with larger samples in New Zealand and Sweden have shown no effect of fluoridation on cognitive development.

4. No city-level differences: If fluoride exposure truly impacted fetal brain development, we would expect to see systematic differences in IQ between fluoridated and non-fluoridated cities. Yet the Canadian studies previously referenced reported virtually identical mean IQ scores (108.07 and 108.21) in non-fluoridated and fluoridated communities.

The Dual Pathway of Protection

One of the most persistent misunderstandings involves how fluoride actually protects teeth. Water fluoridation is unique because it provides two pathways of protection:

1. Direct topical contact when you drink water throughout the day

2. Systemic circulation where fluoride enters your body's water system and re-emerges in saliva, providing continuous low-level protection

While toothpaste delivers a higher concentration of fluoride, it's only effective for a short time after brushing. Water fluoridation increases the frequency of exposure throughout the day, which is important because acid attacks on teeth happen after every meal or snack. (I don’t know about you but I don’t brush after every sip or snack throughout the day!) The systemic benefit of ingested fluoride (e.g., from water) is that it creates a low level of fluoride in saliva, which prevents the acid from being able to attack the enamel throughout the day.

Fluoride's primary mechanism of action is post-eruptive—it works directly on teeth that have already emerged by promoting remineralization of tooth enamel and preventing demineralization. This is why fluoride isn't recommended for infants before teeth erupt. As Dr. Nini Munoz and I explained in "The Well Runs Deep," this dual mechanism represents an elegant public health solution that can't be replaced by occasional dental visits or even regular brushing alone.

What About Fluoride From Food and Water?

Many fluoride skeptics express concern about potential overexposure from multiple sources—water, foods, beverages, and dental products. A February 2025 study in Frontiers in Oral Health brings crucial context: only about 45% of fluoride consumed from foods and beverages is actually bio-accessible (available for absorption), meaning we're not absorbing nearly as much fluoride as previously assumed. (Major shoutout to the brilliant Dr. Kevin Klatt for this information! He wrote an incredible Substack (linked below) on the history of water fluoridation for dental health, the long-time opposition to fluoridation, and the evolving but weak evidence on fluoride’s potential hazards.)

Swimming in a (Fluoridated) Sea of Inadequate Data

This finding explains why, despite increased fluoride sources, we're not seeing widespread fluorosis beyond very mild cases. The recommended level of 0.7 mg/L already accounts for multiple exposure sources – it was specifically reduced from the previous range of 0.7-1.2 mg/L in 2015 to prevent even mild fluorosis while maintaining cavity prevention benefits.

Fluoride naturally occurs in the diet at very low amounts, with tea being the most significant dietary source. Most people don't consume enough fluoride from diet alone to provide dental benefits. Additionally, preliminary results from fluoride's recent inclusion in the National Health and Nutrition Examination Survey (NHANES) don't indicate excessive fluoride excretion beyond WHO-recommended ranges.

The Health Equity Impact

During our radio discussion, my fellow guest suggested there's no evidence that dental issues disproportionately impact communities with lower socioeconomic status. This assertion is blatantly false and contradicted by decades of research.

Children from low-income families have twice the rate of untreated cavities compared to their more affluent peers. Nearly 50% of children on Medicaid do not receive any dental services in a given year. Water fluoridation helps bridge this gap by providing universal protection regardless of income, education, or access to dental care.

The real-world consequences when communities remove fluoride are stark:

• Juneau, Alaska: After ceasing fluoridation in 2007, childhood cavity rates doubled over a decade, with treatment costs increasing by approximately $300 per child and low-income children bearing the heaviest burden.

• Calgary vs. Edmonton: When Calgary discontinued fluoridation while Edmonton maintained it, Calgary's children developed significantly more cavities, with decay rates increasing by 146% in primary teeth—leading Calgary to plan resumption of fluoridation.

• Economic Impact: Every $1 invested in community water fluoridation saves communities approximately $38 in dental treatment costs, with an average savings of $32 per person annually.

With 50% of kids on Medicaid not accessing dental care and proposed cuts threatening to make it worse, this is not the time to remove key preventative measures that help bridge the gap in access.

Beyond Cavities: Oral Health and Systemic Disease

An often overlooked aspect of this debate is the connection between oral health and serious systemic diseases. Poor oral health isn't just about cavities—it has profound implications for overall health.

Many healthcare professionals are more concerned about children developing poor oral health due to dental caries than about vague microbiota changes that occur only at high fluoride exposure levels without proven clinical significance.

The scientific evidence links poor oral health to:

• Cardiovascular disease: Bacteria from periodontal disease can enter the bloodstream, potentially causing endocarditis and increasing risk for heart attack and stroke

• Cognitive decline: Research has established links between poor oral health and increased risk of dementia and Alzheimer's disease

• Respiratory infections: Bacteria from periodontal disease can be aspirated into the lungs, causing pneumonia

• Pregnancy complications: Periodontal disease has been associated with preterm birth and low birth weight

• Diabetes management: Periodontal disease can make diabetes more difficult to control

By preventing dental caries and supporting oral health, fluoridation provides protection that extends far beyond aesthetics or immediate dental health.

The "Europe Doesn't Fluoridate" Myth

Another claim raised during our discussion was that many European countries don't fluoridate their water, suggesting we should follow their example. This oversimplified comparison ignores context: European countries haven't abandoned fluoride as a public health tool—they've implemented it through different delivery systems. Over 13 million Europeans receive fluoridated water, while fluoridated salt reaches more than 70 million people in countries like Germany, Switzerland, France, and Austria. Many nations also employ school-based fluoride programs. Additionally, most European countries provide universal dental coverage and systematic preventive care that the United States lacks, making water fluoridation even more important for ensuring equitable access here.

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The "Big Fluoride" Question

Perhaps the most telling moment in our radio discussion was when a listener asked who profits from water fluoridation. The answer reveals much: if there were a "Big Fluoride" industry, they'd want to STOP fluoridation. Treating dental disease is far more profitable than preventing it. The dental community supports fluoridation despite it reducing the need for lucrative procedures.

The real beneficiaries are children who avoid painful cavities, working adults who avoid lost productivity, low-income families who can't afford regular dental care, and taxpayers who save on Medicaid dental expenses.

We're already seeing concerning trends where dentists report parents declining fluoride varnish treatments due to recent media coverage about fluoride's supposed dangers. There's legitimate worry that if fluoride is removed from water supplies, it could impact insurance coverage for fluoride treatments in clinical settings—creating yet another barrier to care for vulnerable populations.

Moving Forward with Evidence

The oversimplification of this debate must end. We can acknowledge questions while not throwing out a proven public health measure based on methodologically flawed studies.

When my fellow guest advocated for lowering fluoride levels to 0.4 ppm—a move not guided by evidence—I was concerned. If we reduce fluoride below the optimal level needed to support dental health, what's the point? The current recommendation of 0.7 mg/L was carefully determined to balance benefits with any potential risks.

While ongoing studies into fluoride safety are important, the current evidence does not justify changes to water fluoridation practices. The methodological limitations, small effect sizes, and lack of significant findings at relevant concentrations provide no evidence that current U.S. fluoridation practices pose cognitive risks.

A Balanced Path Forward

Rather than taking an all-or-nothing approach, we should consider evidence-based options:

• Targeted Approaches: Instead of eliminating fluoridation entirely, we could provide guidance for potentially vulnerable populations about high-fluoride foods (like tea) and using filters for infant formula preparation if concerned, while maintaining the public health benefit for everyone.

• Research Priorities: We should support further research using standardized, validated biomarkers and study designs to better understand fluoride metabolism in different populations, particularly during pregnancy and early childhood.

• Consensus Approach: Over 250 health organizations have signed on in support of community water fluoridation, reflecting the strong scientific consensus on its safety and benefits. Modifications to current practice should be driven by high-quality evidence rather than methodologically flawed studies.

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The One-Two Punch Against Public Dental Health

What we're witnessing is nothing short of a coordinated assault on public dental health. First, there's a push to remove or reduce fluoride in community water systems based on methodologically flawed studies. Now, the FDA is removing prescription fluoride supplements from the market—creating a dangerous gap in preventive care.

For context, fluoride supplements (tablets, lozenges, or drops) are often prescribed for children who live in areas without fluoridated water to help prevent tooth decay. These supplements have been an important alternative for communities without water fluoridation and for families who don't consume fluoridated tap water.

The FDA's confusing statement that these supplements "have never been approved by the FDA" is particularly puzzling given that dentists and pediatricians have been prescribing them for decades as a standard of care. This appears to be a technicality related to how these products were grandfathered into use before current FDA approval processes were established.

Guidance for Concerned Parents

With all this confusing information circulating, here's what parents need to know about fluoride safety:

• For infants under 6 months: Exclusively breastfed babies don't need fluoride supplements. If using formula, it's safe to prepare it with fluoridated tap water. While there's a small risk of very mild fluorosis (faint white streaks on teeth), this is cosmetic only and doesn't affect dental health.

• For children with their first teeth (6 months to 3 years): Use a smear (grain-of-rice-sized amount) of fluoride toothpaste twice daily and teach them to spit when able. Drinking fluoridated water is safe and beneficial.

• For children 3 years and older: Use a pea-sized amount of fluoride toothpaste twice daily. Community water fluoridation at the recommended level (0.7 mg/L) has not been linked to lower IQ scores or other health issues.

• For children without access to fluoridated water: Talk to your pediatrician about fluoride options. If the FDA's action limits access to prescription supplements, your dentist may recommend other preventive measures like more frequent fluoride varnish applications.

• During pregnancy: The American Academy of Pediatrics states there is "no reason for pregnant people to drink bottled water unless they are concerned about other contaminants." Fluoride in drinking water at recommended levels has not been shown to cause harm to developing fetuses.

This one-two punch could leave millions of children without access to either form of preventive fluoride treatment, potentially reversing decades of progress in reducing dental disease. The most vulnerable communities—those already facing barriers to dental care—will bear the heaviest burden of these changes.

As we navigate this latest controversy, let's ground ourselves in methodologically sound science rather than fear. Our decisions should be guided by the totality of evidence and real-world outcomes, not cherry-picked studies with fundamental flaws.

We've moved beyond the days when tooth decay was life-threatening, but that progress is not guaranteed. Public health is often a victim of its own success, and fluoridation may be yet another example…

Stay Curious,
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