Study: Low Levels of Fluoride impairs Brain Development

Avoid Drinking-water with Flouride

A landmark study by Grandjean et al. has ust been published confirming that very low levels of fluoride exposure during pregnancy impairs the brain development of the child, and at a population level may be causing more damage than lead, mercury, or arsenic.  The paper’s authors ultimately concluded that a maternal urine fluoride concentration of 0.2mg/L was enough to lower IQ by 1 point, that even this impact is likely underestimated, and: 

“These findings provide additional evidence that fluoride is a developmental neurotoxicant … and the benchmark results should inspire a revision of water-fluoride recommendations aimed at protecting pregnant women and young children.”  

A urinary fluoride (UF) concentration of 0.2mg/L is far below what a pregnant woman in a fluoridated community would have, as confirmed by two recent studies.  A study of pregnant women in fluoridated San Francisco, California found a mean UF concentration of 0.74mg/L, and one with participants in fluoridated communities across Canada found a mean UF concentration of 1.06mg/L.  Both levels were significantly higher than those found in women in non-fluoridated communities. 

Grandjean et al.’s study, published in Risk Analysis was a pooled benchmark dose (BMD) analysis of the National Institutes of Health funded ELEMENT and MIREC birth cohorts in Mexico and Canada.  These are the birth cohorts that were used in the studies that found exposure to low-levels of fluoride during pregnancy is linked to cognitive impairment in children (Bashash, 2017Thomas, 2018Green, 2019Till, 2020). 

A Benchmark Dose is used to identify a dose (or concentration) that has a good probability of causing a pre-determined amount of harm. For this BMD analysis, the pre-determined harm was an average predicted IQ drop of 1 point.  What makes this paper so important is that BMD is part of the US Environmental Protection Agency’s (EPA) risk assessment methodology, and the paper’s authors used a 1 IQ point drop as the adverse effect amount because the EPA has used this same level of IQ loss in their own risk assessments and has recommended use of such a level.  It has been well established that a loss of one IQ point leads to a reduced lifetime earning ability of $18,000.  Summed over the whole population we are talking about a loss of billions of dollars earning ability each year. 

Moreover, it’s important to point out that in risk assessments using BMD methodology, it’s standard practice to apply a safety factor on top of the calculated BMD in order to determine a safe reference dose (RfD) to protect the whole population (including the most vulnerable) from harm.  If that safety factor used was the standard safety margin of 10, to account for the variables in population-wide sensitivity, then the EPA might conclude that any urine fluoride concentration above 0.02 mg/L would be unacceptable and “unsafe”.  This is 35-times lower than what the American Dental Association and Centers for Disease Control recommends for fluoridated communities.  

This paper is also incredibly important because the National Toxicology Program (NTP) is in the midst of finalizing their monograph on fluoride’s neurotoxicity for humans, and one of the main recommendations to the NTP from the National Academies of Science, Engineering, and Medicine’s peer review of the NTP’s report was to conduct a BMD before any conclusions could be made about harm from fluoride concentrations lower than 1.5 ppm. NASEM wrote: 

“Little or no conclusive information can be garnered from the revised monograph about the effects of fluoride at low exposure concentrations (less than 1.5 mg/mL). NTP therefore should make it clear that the monograph cannot be used to draw any conclusions regarding low fluoride exposure concentrations, including those typically associated with drinking-water fluoridation. Drawing conclusions about the effects of low fluoride exposures (less than 1.5 mg/mL) would require a full dose–response assessment…” 

Now that this BMD analysis has been completed, and has established a loss of ONE IQ point associated with mother’s fluoride urine level 0.2 ppm, which is well below the average urinary levels of pregnant women in fluoridated communities (in Canada and the USA and other fluoridated countries) it should put to an end to the false claims from fluoridation promoters (including the CDC’s Oral Health Director) that neurocognitiive damage only occurs at concentrations above the fluoride levels used in fluoridation programs (0.7 to 1.2ppm).  The very best human studies on fluoride’s neurotoxicity have actually been done in fluoridated communities at 0.7 ppm or below or equivalent doses as measured in mothers’ urine (Bashash, 2017, Green, 2019 and Till, 2020). And it was the pooled date from these studies that was used in this important BMD analysis. 

Michael Connett, the lead lawyer for the plaintiffs in the lawsuit against the EPA has sent a copy of this BMD analysis to the Judge in our federal TSCA trial against the EPA. On August 20 the judge indicated he was waiting to see this analysis as well as the final version of the NTP review.