Fluoride Action Network

Experts Respond to Inaccurate Criticism of Brain and Thyroid Studies

FAN Bulletin | March 7, 2015

Dear Supporter:

Latest Victories 

  • Bennington, Vermont: Despite aggressive campaigning by a well-organized and well-funded pro-fluoridation coalition, on Tuesday residents of this community of 16,000 voted 1,539 to 1,117 in opposition to fluoridation in an advisory referendum vote.  This is at least the fifth time Bennington residents have voted down fluoridation since the 1960’s.  The Selectmen will now make the final decision at an upcoming meeting, and are expected to honor the vote.  According to news reports, the only local official who publicly supported fluoridation lost the election as well on Tuesday.  Local opposition was organized as soon as the proposal was considered.  Bennington Citizens Against Fluoridated Water, along with a number of area residents, led the efforts that included Letter-to-editor campaigns and a community forum.        
  • Gilford, Pennsylvania: Gilford Water Authority officials have decided to end fluoridation after more than 60 years of practicing it.  The authority sent a letter to water customers stating, “We believe we should not put anything into the water that is not required by regulation to maintain the potability and pH balance of your water.”  The decision has been aggressively criticized by local pro-fluoridation dentists, who plan on attending the water authority’s March 9th meeting to bully the board into reversing their decision.  
  • Sonoma City, California: This week City Councilors voted 3-2 to oppose a proposal by the County government to add fluoride to the city’s drinking water.  The council will be sending a letter of opposition to the Sonoma County Board of Supervisors.  The idea for the vote and letter of opposition came from local fluoride-free campaigner Dawna Gallagher-Stroeh along with others with the Clean Water Sonoma-Marin group, who reached out to Mayor David Cook about the harms and risks associated with fluoridation.

ADA Spokesperson Makes False Statements About NRC Study of Thyroid

A spokesperson for the American Dental Association made an inaccurate statement in the media recently while criticizing the latest study showing hypothyroidism’s link to fluoridation.

Dr. Edmond Hewlett, ADA spokesman and a professor at the UCLA School of Dentistry has been quoted by numerous publications discounting the study, stating that other studies have not uncovered a link between fluoridated water and thyroid problems, saying:

“the 2006 report by the U.S. National Research Council (NRC) found no adverse effects on the thyroid even at levels more than four times greater than that used in fluoridation.”

The quote appeared in a number of articles including those by the Chicago Tribune, HealthDay, and WebMD.  It’s an absolutely false statement, as FAN’s NRC Thyroid webpage makes very clear.  What isn’t clear is whether Dr. Hewlett intentionally lied when making the statement, or if he just lacked the knowledge to make an accurate statement on the matter.

Kathleen Thiessen, Ph.D., who was one of the authors of the 2006 NRC report on fluoride, responded to the inaccurate statement with the following letter to the author of the HealthDay article that quoted Dr. Hewlett:

Regarding a recent HealthDay article by Alan Mozes, which has been used by the Chicago Tribune, WebMD, and probably others: 

The article on fluoride and underactive thyroid, reporting on a recent publication by Stephen Peckham et al., quotes a representative of the American Dental Association as saying that “the 2006 report by the U.S. National Research Council found no adverse effects on the thyroid even at levels more than four times greater than that used in fluoridation.”  This statement by the ADA spokesman is demonstrably inaccurate.

From the NRC report

pp. 262-263: Fluoride exposure in humans is associated with elevated TSH concentrations, increased goiter prevalence, and altered T4 and T3 concentrations. . .  In humans, effects on thyroid function were associated with fluoride exposures of 0.05-0.13 mg/kg/day when iodine intake was adequate and 0.01-0.03 mg/kg/day when iodine intake was inadequate.  

p. 260: The major endocrine effects of fluoride exposures reported in humans include elevated TSH with altered concentrations of T3 and T4. . . .  These effects are summarized in Tables 8-1 and 8-2, together with the approximate intakes or physiological fluoride concentrations that have been typically associated with them thus far.  Table 8-2 shows that several of the effects are associated with average or typical fluoride intakes of 0.05-0.1 mg/kg/day (0.03 with iodine deficiency). . . . A comparison with Chapter 2 (Tables 2-13, 2-14, and 2-15) will show that the 0.03-0.1 mg/kg/day range will be reached by persons with average exposures at fluoride concentrations of 1-4 mg/L in drinking water, especially the children.  The highest intakes (>0.1 mg/kg/d) will be reached by some individuals with high water intakes at 1 mg/L. . . . 


p. 266:  Fluoride is therefore an endocrine disruptor.

p. 234:  Thus, several lines of information indicate an effect of fluoride exposure on thyroid function.

(Note:  I was one of the authors of the 2006 NRC report.  The NRC report is available at http://www.nap.edu/catalog/11571/fluoride-in-drinking-water-a-scientific-review-of-epas-standards)

Kathleen Thiessen, Ph.D.

Oak Ridge Center for Risk Analysis, Inc.

Harvard IQ Researchers Respond to Pro-Fluoridation Criticism

The authors of the 2012 Harvard Meta-analysis that highlighted fluoride’s role as a developmental neurotoxin, Philippe Grandjean, MD, PhD, and Anna Choi, ScD, have written a letter responding to pro-fluoridation criticism of their work by Dr. Jonathan Broadbent.  Broadbent’s counter-study and Grandjean’s letter in response were both published in the American Journal of Public Health.  In his response Grandjean states,

“We are therefore concerned that the safety of elevated fluoride exposure is being exaggerated in ways similar to those employed by vested interests to misconstrue the scientific evidence of other neurotoxicants, such as lead, mercury, and certain pesticides.  Firm dismissal of fluoride as a potential neurotoxic hazard would seem premature.”

See abstract of letter

This isn’t the first time Grandjean has responded to pro-fluoridation efforts to downplay the impact fluoride has on IQ.  In December, he challenged the spin being used by fluoridation promoters.  Grandjean’s commentary (Mottled fluoride debate) appears on his website (Chemical Brain Drain) and is printed in full below. Grandjean explained that for the children tested,

“Their lifetime exposures to fluoride from drinking water covered the full range allowed in the US. Among the findings, children with fluoride-induced mottling of their teeth – even the mildest forms that appears as whitish specks on the enamel – showed lower performance on some neuropsychological tests. This observation runs contrary to popular wisdom that the enamel effects represent a cosmetic problem only and not a sign of toxicity. At least one of five American children has some degree of mottling of their teeth.”

Hear Directly From the Experts on These Latest Studies

This month’s International Fluoride Free Teleconference will be held on Saturday, March 14th at 5:00pm (Eastern Time).  The call will feature a group of scientific experts and researchers discussing the current state of scientific research on fluoridation, including the most recently published studies on IQ, hypothyroidism, and ADHD.  This will be your opportunity to learn the details of these studies, what they mean for the fluoridation debate, and have your questions answered by experts.


Stuart Cooper
Campaign Manager
Fluoride Action Network
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