Fluoride: Friend or Foe?

brushing teeth with fluoride toothpaste

In the 2006 cult classic movie Idiocracy, the main character Joe Bauers takes part in a secret military hibernation experiment, but wakes up 500 years later into a dystopian world where commercialism and anti-intellectualism have run rampant, with IQ rates that have plummeted. He is found to be the smartest person in the world and is appointed to become the President. 

Whenever I see studies linking fluoride ingestion with lowered IQ rates, this movie comes to mind. Why an I concerned?

Adding fluoride to our nation’s water supply has been touted as a major public health success story, resulting in significantly lowered rates of cavities (~25%). However, ever since the inception of the program in 1945, there have been strong opinions for and against it. I’ve always had mixed feelings about fluoride, but over the years, a handful of studies linking fluoride levels to lowered IQ levels led me into a rabbit hole of confusing, often conflicting studies. What I explain in this article is my reason for coming to the conclusion that ultimately, we’re better off without fluoride in our water supply. 

Fluoride’s Link to Lower IQ

There have been a myriad of studies over many decades associating fluoride with various health conditions, including flourosis,  cancer, bone fractures, hypothyroidism, acne, earlier puberty in girls, pineal gland calcification, and lowered intelligence. Numerous arguments are made countering the above associations as well.  

A 2012 systematic review and meta-analysis of 27 studies over 22 years from Harvard combined all the highest quality studies on fluoride exposure and IQ, showing that children living in areas with higher fluoride exposure had significantly lower IQ scores (about 7 points). Needless to say, this study attracted a lot of headlines and media coverage.

In 2017, researchers from the the United States, Canada and Mexico found that children had a 6 point drop in IQ score with each 1 mg/L increase in maternal urine fluoride levels.  

Just last month in JAMA Pediatrics, researchers from York University in Toronto published results showing that in mothers living in areas of fluoride water during pregnancy (compared to non-fluoridated water) had children with lower IQ rates. They measured the mother’s urine fluoride levels as well as estimated fluoride intake levels based on dietary factors and local water supply fluoride concentrations. They found that for every 1 ml/L increase in maternal urine fluoride levels, IQ levels dropped by 4.5 points, but in boys only. When maternal fluoride intake was measured, IQ diminished by 3.7 points in both boys and girls.

This study went against the grain amongst the medical and governmental establishment support for water fluoridation, leading to an editorial comment by JAMA, stating, “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 first two two articles were published in an open-source peer-reviewed public health journal funded by the National Institute of Environmental Health Sciences (Environmental health perspectives), but the third one was published in a major main-stream medical journal (JAMA Pediatrics). 

How Toxic is Fluoride?

One mg/L is equivalent to 50 µmol/L, or 1 part per million (ppm). Rats exposed to 1 ppm of water with fluoride for 1 year showed structural brain changes and increased uptake of aluminum in brain tissue. This is supported by another paper showing that higher levels of aluminum are taken up by the pineal gland if accompanied by fluoride. Another study showed that addition of sodium fluoride to explants of embryonic rat palates lead to retardation of the palatal shelf growth and lack of fusion. In addition, elderly people were found to have higher levels of fluoride/calcium ratio in the pineal gland compared to bone. Lastly, lack of melatonin production due to a calcified pineal gland us thought to be related to premature aging and Alzheimer’s disease. 

There are also numerous reports of death by acute fluoride ingestion. It’s puzzling to see the warning against swallowing any amount of toothpaste. Note that every fluoride toothpaste has a disclaimer on the back which states “WARNING: Keep out of reach of children under 6 years of age. If more than used for brushing is accidentally swallowed, get medical help or contact a poison-control center right away.” I wonder how many kids swallow some portion of their bubble-gum flavored toothpaste every day.

Fluoride’s Link to Jaw and Airway Narrowing

One of the basic concept in my field (otorhinolarygology/ENT) is that sodium fluoride can be used slow down hearing loss in otosclerosis. This is a condition where the last bone in the middle ear (called the stapes) has overgrowth of new bone, preventing proper vibration of the stapes footplate onto the inner ear and leading to hearing loss.  It’s like an engine piston without any oil, adding more friction. Besides surgery, one of the older medical treatment option is to give sodium fluoride. Fluoride is thought to prematurely mature the immature bone on the stapes, preventing it from worsening hearing loss. I’ve personally given sodium fluoride to patients in the early part of my career to prevent worsening otosclerosis. But in retrospect, this brings up the obvious question: Where else besides the teeth and middle ear is fluoride reaching?

This led me to studies that show fluoride’s potential effect on bone development. One study found that rats given palatal expanders had less movement if given water with fluoride. Sodium fluoride has been shown to alter bone cell’s building and breakdown abilities. A number of studies have reported increased risk of bony fractures after taking sodium fluoride. Post-menopausal women given sodium fluoride to prevent osteoporosis had a higher rate of non-spine fractures compares to controls. Rates of fluorosis (darkening of teeth with white streaks due to excessive fluoride ingestion) are thought to be over 40% in teens. What can be inferred from these studies is that fluoride can lower the rate of cavities at the cost of potentially altering systemic bone metabolism and development. 


There are a number of other risk factors for malocclusion and crooked teeth, including prematurity, bottle-feeding, soft diets, thumb sucking, pacifier use, and nasal congestion. I recommend adding fluoride to this list. 

What I’m suggesting here is only a small portion of what the movie Idiocracy portrays, but there are dozens if not hundreds of other toxins, poor diets and everything else that makes us sicker, fatter, and less focused. Oftentimes, life can imitate art.

Please note: I reserve the right to delete comments that are offensive or off-topic.

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5 thoughts on “Fluoride: Friend or Foe?

  1. Excellent post! Thank you so much. I really appreciate you sharing your research and expertise in an easily accessible blog post.

  2. Hello Dr. park, things through the internet should be explained more briefly, you write too much to mean something, you should simplify more what you want to explain and write or speak less…

  3. Gina,

    There are some studies showing that topical fluoride can be beneficial in preventing cavities, but taking it orally may not be worth the risk. There are isolated case reports of young children dying of fluoride overdose with toothpaste ingestion. My recommendation in general is to avoid fluoride if you can.