“It is apparent that fluorides have the ability to interfere with the functions of the brain.” (National Research Council, 2006)
Fluoride’s Neurotoxicity
Fluoride’s ability to damage the brain is one of the most active areas of fluoride research today. Over 600 studies have found that fluoride can damage the brain. This research includes:
- Over 300 animal studies showing that prolonged exposure to varying levels of fluoride can damage the brain.
- 78 human studies linking 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 (impaired visual-spatial organization).
- 3 human studies linking fluoride exposure with impaired fetal brain development.
- 11 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 comprehensive monograph and meta-analysis on fluoride’s neurotoxicity authored by the U.S. National Toxicology Program (NTP) – have raised red flags about the potential for low levels of fluoride to harm brain development in some members of the population.
The NTP Fluoride Neurotoxicity Review (2023)
The U.S. National Toxicology Program’s 7-year systematic review on fluoride’s neurotoxicity is the most comprehensive study yet conducted. The report found that:
“52 of 55 studies found lower IQ with higher #fluoride exposures, demonstrating remarkable consistency. Of the 19 studies rated higher quality, 18 found lowering of IQ. The meta-analysis could not detect any safe exposure.”
The report was blocked from publication by top U.S. health officials but due to pressure from the judge in the historic TSCA fluoride lawsuit it was made available to the attorneys in the trial and eventually it was made public as a draft document. An overview of the NTP review can be found here.
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, Grandjean and Landrigan, write:
“Our very great concern is that children worldwide are being exposed to unrecognized toxic chemicals that are silently eroding intelligence, disrupting behaviors, truncating future achievements, and damaging societies, perhaps most seriously in developing countries.”
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.”
The 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. 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 Harvard 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.”
The NRC panel only had 3 IQ studies from China to evaluate. Today there are 78 IQ studies.