Fluoride’s ability to damage the brain is one of the most active areas of fluoride research today. Over 400 studies have found that fluoride is a neurotoxin (a chemical that can damage the brain). This research includes:
- Over 200 animal studies showing that prolonged exposure to varying levels of fluoride can damage the brain, particularly when coupled with an iodine deficiency, or aluminum excess;
- 63 human studies linking moderately high fluoride exposures with reduced intelligence;
- Over 60 animal studies reporting that mice or rats ingesting fluoride have an impaired capacity to learn and/or remember;
- 12 studies (7 human, 5 animal) linking fluoride with neurobehavioral deficits (e.g., impaired visual-spatial organization);
- 3 human studies linking fluoride exposure with impaired fetal brain development.
- 7 Mother-Offspring studies linking certain levels of fluoride in the urine of pregnant women to reduced IQ in their offspring.
Based on this accumulating body of research, several prestigious reviews — including a report authored by the U.S. National Research Council, a meta-analysis published by a team of Harvard scientists, a review published in The Lancet, and a 2017 U.S.-funded 12-year study that found a link between fluoride in the urine of pregnant women and lower measures of intelligence in their children — have raised red flags about the potential for low levels of fluoride to harm brain development in some members of the population.
The NRC Review (2006)
In 2006, the National Research Council (NRC) stated that “it is apparent that fluorides have the ability to interfere with the functions of the brain.” In addition to calling for U.S.-based research on fluoride’s IQ effects, the NRC expressed concern about fluoride’s possible contribution to dementia. According to the NRC:
“Studies of populations exposed to different concentrations of fluoride should be undertaken to evaluate neurochemical changes that may be associated with dementia. Consideration should be given to assessing effects from chronic exposure, effects that might be delayed or occur late-in-life, and individual susceptibility.”
Harvard Review (2012)
In July of 2012, a team of Harvard researchers published a “meta-analysis” of 27 studies that have investigated the relationship between fluoride and human intelligence. (Choi 2012) The overwhelming majority of these studies found that fluoride exposure was associated with reduced IQ in children. In fact, 26 of the 27 studies that met the Harvard team’s inclusion criteria found a relationship between elevated fluoride and reduced IQ. The Harvard team thus concluded that fluoride’s effect on the developing brain of children should be a “high research priority” in countries like the U.S. where, despite mass fluoridation programs, no studies have yet been conducted to investigate the issue.
The Lancet Review (2014)
In March of 2014, the prestigious medical journal The Lancet published a review of “developmental neurotoxicity” which concluded that fluoride is one of only 11 chemicals that is known to damage the developing brain. Developmental neurotoxins are capable of causing widespread brain disorders such as autism, attention deficit hyperactivity disorder, learning disabilities, and other cognitive impairments. The harm is often untreatable and permanent.
The authors of The Lancet review, which included Harvard scientist Philippe Grandjea, write:
In a bulletin posted on the Harvard School of Public Health website, Grandjean notes that:
“Fluoride seems to fit in with lead, mercury, and other poisons that cause chemical brain drain. The effect of each toxicant may seem small, but the combined damage on a population scale can be serious, especially because the brain power of the next generation is crucial to all of us.”
Rat Studies Link Brain Cell Damage With Aluminum and Fluoride in Water
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Summary of 2011 Fluoride Research
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Fluoride & the Brain
The most recent Chinese study on fluoride & the brain was posted on PubMed just last week. The study looked at the effect of fluoride on the hippocampal region of rat brain, and concluded that: “Fluoride may go through the blood-brain barrier and accumulate in rat hippocampus, and inhibit the activity of cholinesterase.”
Fluoride & IQ: The 63 Studies
As of November 2019, a total of 71 studies have investigated the relationship between fluoride and human intelligence. Of these investigations, 63 studies have found that elevated fluoride exposure is associated with reduced IQ in humans, while over 60 animal studies have found that fluoride exposure impairs the learning and/or
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The human placenta does not prevent the passage of fluoride from a pregnant mother's bloodstream to the fetus. As a result, a fetus can be harmed by fluoride ingested pregnancy. Based on research from China, the fetal brain is one of the organs susceptible to fluoride poisoning. As highlighted by the excerpts
Fluoride's Neurobehavioral Effects in Humans & Animals
In addition to studies linking fluoride to reduced IQ in humans, and impaired learning/memory in animals, human and animal studies have also linked fluoride to a variety of other neurobehavioral effects. These studies, which are excerpted below, provide yet further evidence that fluoride is a neurotoxin. The latest findings were reported
Fluoride & the Brain: An Interview with Dr. Phyllis Mullenix
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