If you grew up hearing that fluoride is good for your teeth, you’re not alone. It’s in toothpaste, added to many public water supplies, and often praised as a key player in dental health. But new research published in JAMA Pediatrics in early 2025 is prompting a shift in how we think about fluoride—especially for children.
In one of the most comprehensive reviews of its kind, researchers found that fluoride exposure is consistently linked to lower IQ scores in children across a wide range of studies from around the world. While that sounds alarming, there’s a lot to unpack here.
The study, led by Dr. Kyla Taylor and colleagues at the National Institutes of Health, reviewed 74 different studies involving over 20,000 children. These weren’t just any studies—they went through a rigorous process to assess their quality, methods, and potential biases.
Here’s what the researchers looked at:
- Fluoride levels in drinking water, food, and urine.
- IQ test results for kids exposed to different levels of fluoride.
- Data from 13 countries, including China, India, Canada, Iran, and Mexico.
Importantly, they reviewed both older, group-based studies (like comparing one town’s fluoride levels to another) and newer studies that tracked individual children over time and tested their fluoride exposure through urine samples.
What Did They Find?
The short version? More fluoride exposure was linked to lower IQ scores.
But let’s go deeper:
1. Overall, more fluoride = lower IQ
Across all 74 studies, there was a consistent trend: children exposed to higher levels of fluoride—whether through drinking water, food, or other sources—tended to score lower on IQ tests.
The effect wasn’t just a fluke in one country or a handful of studies. It was seen in nearly every region and across multiple types of research designs.
2. Even moderate fluoride levels showed effects
This is one of the most concerning takeaways. Even when researchers looked only at fluoride levels below the World Health Organization’s recommended limit (1.5 mg/L), the link to lower IQ remained in many studies.
In fact, in studies that measured fluoride in children’s urine, IQ scores dropped by about 1.6 points for every 1 mg/L increase in fluoride. That might not sound like a lot, but on a population level, it’s enough to shift the average IQ—and increase the number of kids falling into the lower end of the IQ range.
3. Prenatal and early childhood exposure matter most
Several of the most high-quality studies tracked fluoride levels during pregnancy and early childhood. These found that fluoride exposure during pregnancy was just as important—if not more—than after birth.
This makes sense, since the brain is still developing rapidly in utero and in the early years of life.
Why IQ Matters
IQ isn’t the be-all and end-all of intelligence or success, but it’s often used in research because it’s a measurable way to track cognitive development. A drop of even 1-2 IQ points across a population is statistically significant.
Imagine a bell curve. A shift in the average IQ means more kids fall into the “low IQ” category, potentially affecting things like learning abilities, school performance, and future job opportunities.
Why Is This Just Becoming a Concern?
You might wonder—if fluoride has been in our water for decades, why is this coming up now?
A few reasons:
- Newer, more sensitive methods: Recent studies are better at measuring individual fluoride exposure, especially through urine tests, which account for all sources—not just water.
- More focus on neurodevelopment: We now understand that subtle chemical exposures can affect brain development, much like lead or mercury can.
- Growing body of research: Earlier studies were mostly from areas with extremely high fluoride levels. But newer studies in countries like Canada and Mexico have shown similar effects at much lower levels—levels more common in the U.S. and Canada.
Is This a Global Issue?
Yes. Although most of the studies were from China and India—where natural fluoride levels in groundwater can be quite high—many were also from countries with water fluoridation practices similar to North America.
Some recent, high-quality studies from Canada and Mexico tracked prenatal fluoride exposure and found similar results. These studies are especially relevant for North American families, as they reflect more typical fluoride levels found in cities with fluoridated tap water.
Interestingly, the study notes that no U.S.-based studies were included—pointing to a gap in research that needs to be filled.
So… Should Kids Stop Drinking Tap Water?
Here’s where things get tricky.
Tap water is still one of the best ways to prevent cavities, especially in children. The U.S. and Canada both have long-standing policies to fluoridate public water supplies at a level around 0.7 mg/L, considered safe for dental health.
But this new research suggests that even levels below 1.5 mg/L might not be completely risk-free when it comes to brain development. In fact, in studies that looked only at low-risk-of-bias data, fluoride levels under 1.5 mg/L were still associated with small IQ drops—especially when measured in urine.
It’s a tough balancing act: preventing tooth decay vs. protecting brain development.
What Can Parents Do?
While we wait for more guidance from public health officials, here are a few things you can do if you’re concerned:
1. Use filtered water for babies and toddlers
Babies and young children are especially vulnerable during key developmental periods. Consider using filtered or fluoride-free water when mixing formula, especially if you live in an area with fluoridated water.
Look for reverse osmosis or activated alumina filters, as these are effective at removing fluoride.
2. Check your local water report
Municipalities usually publish annual water quality reports. Find out how much fluoride is in your local water. If you’re on a well, consider having your water tested.
3. Be mindful of fluoride toothpaste for young kids
The American Dental Association recommends only a rice-sized smear of fluoride toothpaste for children under 3, and a pea-sized amount for children ages 3–6. Always supervise brushing to make sure they’re not swallowing it.
4. Talk to your pediatrician or dentist
If you have concerns, bring them up. Medical professionals are increasingly aware of the fluoride-IQ debate and can help you weigh the risks and benefits based on your child’s age and health needs.
This study doesn’t call for an immediate end to fluoridation—but it does suggest that a re-evaluation may be overdue.
Historically, fluoride was added to water based on what was best for dental health. But now, we need to ask: what’s best for children’s overall development?
Researchers are urging public health officials to consider these findings when assessing fluoride policies. That doesn’t mean scrapping fluoridation overnight, but rather conducting more research, monitoring fluoride levels more closely, and offering options for families who may want to limit their children’s exposure.
Like many things in parenting and health, the fluoride question isn’t black and white.
Yes, fluoride helps prevent cavities. But emerging science is telling us it may come with trade-offs when it comes to brain development—especially during pregnancy and early childhood.
If you’re feeling overwhelmed, that’s totally understandable. The good news is, small, mindful changes—like filtering water for babies or watching toothpaste use—can go a long way.
And as always, staying informed is one of the best things you can do for your child’s health.
References:
- Taylor KW, Eftim SE, Sibrizzi CA, et al. Fluoride Exposure and Children’s IQ Scores: A Systematic Review and Meta-Analysis. JAMA Pediatrics. 2025;179(3):282-292. doi:10.1001/jamapediatrics.2024.5542
- Centers for Disease Control and Prevention. Community Water Fluoridation.
- World Health Organization. Guidelines for Drinking-Water Quality.
