The People's Perspective on Medicine

Does Fluoride in the Water Impact Children’s IQ?

The majority of Americans are exposed to fluoride in water and toothpaste. A new study reports that prenatal exposure may affect young children. What to do?
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Ever since fluoride was first added to drinking water in Grand Rapids, Michigan, on January 26, 1945, it has been controversial. The “fluoride wars” have been raging ever since. There is little doubt that when municipal water authorities put fluoride in the water supply, it helps prevent tooth decay.

Are there any downsides about fluoride that people should know about? A new study suggests that children’s IQ may be impacted by early exposure to fluoride in the water (JAMA Pediatrics, online, Aug. 19, 2019).

Dentists and Public Health Officials Love Fluoride:

Although there have been questions about fluoride’s potential toxicity, most public health officials dismiss them. They consider water fluoridation one of the top ten public health achievements of the last century.

The Cochrane Collaboration is an independent collection of scientists and scholars. Cochrane describes itself this way:

“Cochrane is for anyone interested in using high-quality information to make health decisions. Whether you are a doctor or nurse, patient or carer, researcher or funder, Cochrane evidence provides a powerful tool to enhance your healthcare knowledge and decision making.”

Here is what Cochrane says about fluoride in the water to prevent tooth decay (Cochrane Database of Systematic Reviews, June 18, 2015): 

“We carried out this review to evaluate the effects of fluoride in water (added fluoride or naturally occurring) on the prevention of tooth decay and markings on teeth (dental fluorosis).”

“We reviewed 20 studies on the effects of fluoridated water on tooth decay and 135 studies on dental fluorosis. The evidence is up to date at 19 February 2015.

“Our review found that water fluoridation is effective at reducing levels of tooth decay among children. The introduction of water fluoridation resulted in children having 35% fewer decayed, missing and filled baby teeth and 26% fewer decayed, missing and filled permanent teeth.”

“Within the ‘before and after’ studies we were looking for, we did not find any on the benefits of fluoridated water for adults.”

The Flip Side of the Fluoride Debate:

I remember riding in the car with my parents in the 1950s when a radio announcer insisted, with great passion, that fluoridation was a communist plot to make Americans dumber. My parents thought the guy was a total kook. Most Americans agreed.

Over the course of the following decades, two-thirds of U.S. citizens now ingest fluoride in the water. In addition, there is fluoride in toothpaste and mouthwash.

Fluoride and IQ?

A study in JAMA Pediatrics (online, Aug. 19, 2019) suggests that when pregnant women are exposed to higher levels of fluoride, their infants may have lower IQs as they grow up.

The researchers studied 512 mother-child pairs from six Canadian cities. Roughly 40% of them had fluoride in the water. Urine samples during pregnancy measured the mothers’ fluoride exposure. The investigators also estimated exposure based on the women’s reports of their drinking water sources during pregnancy.

They found that women with the highest levels of fluoride in their urine had sons with modestly lower IQ scores at three to four years of age. When the researchers considered total fluoride exposure of the mothers during pregnancy, boys and girls were affected.

Other Fluoride Research:

This is not the first study to suggest that fluoride in water might be neurotoxic for developing brains.

In the JAMA Pediatrics article, the authors point out: 

“Fluoride crosses the placenta, and laboratory studies show that it accumulates in brain regions involved in learning and memory and alters proteins and neurotransmitters in the central nervous system. Higher fluoride exposure from drinking water has been associated with lower children’s intelligence in a meta-analysis of 27 epidemiologic studies and in studies including biomarkers of fluoride exposure.”

What Conclusions Can We Draw?

The authors offer the following summation of their research:

“In this prospective birth cohort study from 6 cities in Canada, higher levels of fluoride exposure during pregnancy were associated with lower IQ scores in children measured at age 3 to 4 years. These findings were observed at fluoride levels typically found in white North American women. This indicates the possible need to reduce fluoride intake during pregnancy.”

Is Fluoride in Water Worrisome?

This study was only about prenatal fluoride exposure. The results are likely to be divisive. The editors of JAMA Pediatrics acknowledged the sensitivity of the topic.

Here is what they said in justifying publication of this research (JAMA Pediatrics, Aug. 19, 2019):

“This decision to publish this article was not easy. Given the nature of the findings and their potential implications, we subjected it to additional scrutiny for its methods and the presentation of its findings. The mission of the journal is to ensure that child health is optimized by bringing the best available evidence to the fore. Publishing it serves as testament to the fact that JAMA Pediatrics is committed to disseminating the best science based entirely on the rigor of the methods and the soundness of the hypotheses tested, regardless of how contentious the results may be.”

What Are Your Thoughts About Fluoride in Water?

We know that this research will be controversial. There is another recent study that adds to concerns about the safety of fluoride in water. Here is a link to fluoride exposure and kidney and liver function in adolescents. 

Please share your thoughts in the comment section. This topic is controversial. Please be thoughtful in your response.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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  • Green, R., et al, "Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada," JAMA Pediatrics, online, Aug. 19, 2019, doi:10.1001/jamapediatrics.2019.1729
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Prior to this study, there have been 50 human studies, and 300 animal and laboratory studies that confirm similar results. The connection between fluoride intake and IQ reduction is now solid. The editors of this study compared fluoride to lead in this regard. What to do? As the editors said, it is time to recommend that pregnant women use bottled water to avoid the fluoride. And the US Centers for Disease Control needs to stop promoting and paying for water fluoridation.

There is a lawsuit already underway in federal court in San Francisco that has the potential to stop all fluoridation in the country. This trial is set to be heard starting February 3, 2020, and will be based on the law and the published science. Any IQ reduction (brain damage) has disastrous consequences for our children and society. Brain damage is permanent. Any reduction in tooth decay is inconsequential in comparison. There are better ways than water fluoridation to reduce tooth decay.

I disagree with adding fluoride to drinking water. It is a drug when you think about it and it can be dangerous so why add it to water where a person then needs to purchase an expensive filtration system to remove it? The possibility that it can impact a child’s IQ is just one more reason to get it out of our water supply. There are plenty of ways to get fluoride if you are someone who thinks ingesting fluoride is a good idea.

The thing to recognize is that fluoride added to public water is non-consensual dental treatment of everyone who depends on that shared public resource. A shared public resource needs to be safe for everybody. When doctors and scientists are debating whether or not fluoride in water is harmful to some, that makes it a non-consensual medical/public health experiment. Non-consensual experimentation on humans is a violation of medical ethics as stated in the 1947 Nuremberg Code and a human rights violation as stated in the 2005 UNESCO Universal Declaration on Bioethics and Human Rights. There is absolutely no scientific, regulatory, or ethical justification for telling people to keep on using fluoridated water until it’s been proved beyond a shadow of a doubt that it’s actually safe. When there’s any question they should be calling a halt to it.

Please note the warning on fluoride toothpaste. It says to call poison control if more is swallowed than the amount used for brushing. The amount of fluoride in a glass of water is the same as the amount in a dab of fluoride toothpaste. How many glasses of water do you or your children drink in a day? Different federal agencies and professional organizations hold entrenched policies and beliefs that they do not want to change. Since it is also widely recognized (including by the CDC in 1999) that topical fluoride applications have some effect against tooth decay while ingested fluoride has scarcely any to none, the smart choice is to avoid swallowing fluoride, especially pregnant women and young children. If you are curious about why non-consensual fluoride treatment is still promoted you might want to start your investigation with this website by EPA scientists who have been objecting to fluoridation for more than two decades due to the scientific evidence of its toxicity which is roughly the same as lead.

An edit to my 8/25 comment, probably intended to be helpful, changed a significant word. I wrote “There is absolutely no . . . justification for telling people to keep on using fluoridated water until it’s been proved beyond a shadow of a doubt that it’s actually HARMFUL (was changed to ‘safe’).” Why would public health officials tell pregnant women: “Fluoridated water may harm your unborn children, but we still aren’t sure it will, so don’t worry, go ahead and use it.” ?

This highlights another aspect of unethical non-consensual fluoride treatment: Science can’t prove that a drug is never harmful, i.e. that it is ‘safe’. It can only do tests and conclude that it was not shown to be harmful in any of the tests that were done. Or some adverse effects may be found, making it necessary to weigh risk vs. benefit. Because of known and unknown risks, medical ethics require informed consent for treatment. The Green et al. fluoride study corroborates a long list of other human and animal studies that show neurological injury, meaning that there IS a risk to ingesting “small” amounts of fluoride. Adding fluoride to public water is treatment of people without their consent with medication that has known risks.

So the question isn’t whether it affects IQ, but whether that effect is significant or not.

The standard deviation on the Wechsler is 15 points. The researchers found only significance for boys and IQ score when using actual fluoride concentrations of 5.01 points. That is 1/3 of a standard deviation — not even enough to justify raising an eyebrow. There was no significant correlation between actual fluoride exposure and girls’ IQ.

In short, with observed, actual fluoride exposure, there is a small correlation of a 5 point decrease in boys only. (They only found cross-gender significance at the p=0.04 level when they added in their own questionable “estimated” fluoride intake — something that has no scientific validation [which they authors acknowledged]). It would be nice if an article like this put some things into context, instead of just repeating the authors’ assertions without batting an eye, no?

Whether you should go off of tap water or not depends on whether you believe you will be a better parent than most, who struggle with their kids teeth health. Teeth health is whole ‘nother risk factor for health issues in children, hence the reason for fluoridation in the first place.

I grew up in the panhandle (top) of Texas in the 50’s and 60’s. At that time, most towns and cities used well water. The water in the panhandle is full of fluoride. Many children had stained teeth from the fluoride (fluorosis). The local dentist said our area was the biggest area of fluorosis in the world, but very few children had tooth decay. When my brother was having a physical in the army, his army doctor commented when he noticed his teeth. He said that not only does fluoride prevent tooth decay, but also makes strong bones. He said children in those areas have fewer broken bone. I guess the bone question and the IQ question will need to be researched more. From the many people I’ve known, I’d vote yes to only strong teeth and bones.

I stopped using fluoride toothpaste over 15 years ago. Bad teeth run in my family but since stopping the use of fluorinated toothpaste I stopped getting cavities. I have also read that fluoride makes your bones brittle. I feel that the use of fluoride should be stopped and many municipalities have done so.

I live in the Chicago area where water from Lake Michigan is treated and fluoridated. I drive several miles to the forest preserve to fill bottles at a pump whose source is a spring-fed well. Judging by the line of other water-fillers, my quest for chlorine-free, fluoride-free and pharmaceutical-free water is shared by thousands in the area. The water-fillers collaboratively paid for water testing and the water is elevated for iron, sodium and a few other minerals. Every week I fill 8 gallons for drinking.

By the time I was pregnant with my second child in 1969, fluoride was in our city water, so I was drinking it and cooking with it. That child has an outstanding IQ and holds degrees from 2 different Universities, speaks several languages and as a child, scored extremely high on all those government tests and later on the SATs, etc. I believe he actually has a higher IQ than his older brother, who was born before fluoride was in our city water.

The benefits of flouride in the water are obvious. Just look at me and my mother. I was born when the water was flouridated; it was not so in my mother’s childhood. Her teeth are a disaster. I, on the other hand, have all my natural teeth (except my wisdom teeth which were removed). They are strong and healthy.

Also, I have a very high I. Q. While this statement might seem immodest, it is simply factual. So, I’m wondering just how much of a risk flouridation of drinking water and use of flouridated toothpaste really is to I. Q. levels. Would I have been the next Einstein if only I hadn’t been exposed to flouride?! Wow!!! (Er, probably not.)

So, here we have obvious benefits and debatable risks.
Perhaps we should not be too quick to eliminate the use of flouride.

Or could at least some of the effect be caused by the impact of flouride on thyroid hormones?

I would like to have clean water–without flouride. For those who want flouride, there are plenty of toothpastes and other products available. Why should entire communities be forced to have a potential toxin in their water? In reality, no one really knows the long-term effects of ingested flouride in humans. In my view, it’s unreasonable to expose the many of us to this unnecesary risk, for the convenience of a few.

Unfortunately, this People’s Pharmacy report and the JAMA Pediatrics report do not refer to the other two large NIH-funded studies of mother-child pairs in Mexico also based on maternal urine levels published in 2017 and 2018. One looked at IQ scores and found the same dose-response effect as the Canadian study. The other found a dose-response increase in ADHD diagnoses. Evidence of neurological injury from fluoride in animal testing has existed for at least 25 years.

The account of the Cochrane Review findings is not accurate. Cochrane was more equivocal, saying that studies done before 1975 with procedural weaknesses showed effect for children but questioned their relevance today. There was a massive US study of 39,207 American children done by the National Institute of Dental Research in 1988 that showed no benefit to children drinking fluoridated water.

The distinction between ingesting fluoride and topical application in toothpaste and other procedures was established 20 years ago. In 1999 the CDC stated “. . . fluoride’s predominant effect is posteruptive and topical. . . . The prevalence of dental caries in a population is not inversely related to the concentration of fluoride in enamel, and a higher concentration of enamel fluoride is not necessarily more efficacious in preventing dental caries.”
What’s really a matter of concern in all this is that the People’s Pharmacy and all of our medical and public health authorities are failing to recognize that when there is evidence of harm from non-consensual fluoride treatment in public water and ongoing scientific debate about it, imposing that non-consensual treatment on people is non-consensual medical experimentation which is clearly a violation of medical ethics and human rights. Seven decades of pro-fluoridation indoctrination in our medical and dental schools and the news media has blinded all of us to this essential fact. Fluoridation in the US was started on January 25, 1945, just two days before the liberation of Auschwitz; and it was proudly presented by the US Public Health Service as a human experiment. It has continued to be the subject scientific debate even as it has been expanded to roughly 75% of all US water systems. There are many more facts to know about the problems with artificial water fluoridation, but I will stop with the website of EPA scientists who have been calling for an end to fluoridation for more than two decades:

From what I have read I do not trust flouride in water or toothpaste but it is hard to avoid. I know of at least one case of the flouride in water killing livestock. And when they say on toothpaste labels, because of the fluoride “Do not use with young children,” I do not want it either.

The Fluoride article is misleading. The debate about fluoride in the water is old. Fluoride in drinking water at 1 part/million protects teeth. You mention “higher levels” as harmful but don’t name those levels. I do not consider this article more than social commentary until you back up claims with statistics.

Thanks for this article. But you left out the most important part of the story: ingestion via food. All soda, beer, bread and any processed food that is manufactured in a location that has fluoridation contains fluoride. The only exceptions occur when the manufacturer takes steps to remove the fluoride (almost never). This is how we are ingesting the majority, not by brushing our teeth. Fluoride is a poison. The dose needed for death is 5mg per 2.2 lbs of body weight.

Poison in small quantities is still poison. It is almost impossible to eliminate this toxic substance from your life but you can limit exposure. First drink only pure water. Distilled or a source from a public water supply that has gone thru reverse osmosis. Drink beer in bottles and from brewers in the EU. Don’t believe the fallacy that brewing removes fluoride. It doesn’t.

After learning that fluoride can cause osteoarthritis, I began filtering my drinking and cooking water. My arthritis symptoms declined dramatically and quickly. Now in my mid-60s, I am more flexible and pain-free than I’ve been in years.

The US Dept of Health and Human Services says adults living in fluoridated communities ingest 1.6 to 6.6 mg of fluoride daily (DHHS 1991). Those amounts can cause arthritic symptoms and the early stages of skeletal fluorosis. (Ge 2006; Bao 2003; Savas 2001; Tartatovskaya 1995; Czerwinski 1988; Chen 1988)

Cutting down on fluoride intake can be as simple as using a pitcher-style filter. Not all brands remove fluoride, however, so you’ll need to do some research. I won’t mention the brand I use, but it’s readily available in retail stores.

I don’t trust flouride healthwise…I have been using Spry toothpaste for years and no teeth problems. Thank you Xylitol.

I drank fluoridated water and used fluoride toothpaste when I was pregnant with my daughter. She drank fluoridated water and used fluoride toothpaste. If her IQ were any higher than it is, it would be frightening.

” Higher fluoride exposure from drinking water has been associated with lower children’s intelligence in a meta-analysis of 27 epidemiologic studies and in studies including biomarkers of fluoride exposure.””
But, in my opinion, lower children’s intelligence without indicating how much lower is useless information.
If the IQ drop is minimal we should ignore it.

Judith, the drop is very small, just a few points. Any parent could ignore it. Still, on a population-wide basis it could be something to consider.

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