Juliet Guichon's misrepresentation of scientific findings by Zhao et al.

How public health authorities in Calgary and fluoride "experts" are manipulating and misrepresenting the science on fluoride toxicity
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Juliet Guichon's misrepresentation of scientific findings by Zhao et al.

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September 28, 2021 [Updated Oct. 8, 2021]

On June 11, 2020, Prof. Juliet Guichon (University of Calgary) and her colleagues Ian Mitchell, Christopher Doig, M. John Gill, James Dickinson, and Margaret Russell (all members of the O'Brien Institute for Public Health) published a hyperlinked opinion piece online, entitled "Fluoridation and the ‘sciency’ facts of critics".

The article appeared on the HealthyDebate.ca website.

The piece was an attack on the Fluoride Action Network (FAN), an anti-fluoridation group based in the USA, accusing them of misrepresenting studies.

One paragraph, in particular, caught our eye.

Guichon et al. wrote:
Beyond citing irrelevant or poorly conducted research, FAN has also misrepresented studies. The group has cited an animal study that purported to find “that fluoride and low iodine have ‘mutually interacting effects’ on the thyroid gland.” But the coauthors of this study wrote it is “generally believed that fluorine does not influence either thyroid function or structure” at the amount used in water fluoridation. The authors noted an exception “if fluorine intake is extremely high such as in an endemic fluorosis area” but such circumstances are extraordinarily unlikely in U.S. or Canadian communities.

We immediately realized that the authors were referring to the important animal study by Zhao et al. (1998), a work that involved three universities from China and Japan over a period of 10 years.

Zhao et al. investigated the long-term effects of various doses of fluoride and iodine in a mouse model and found mutually interacting effects on both thyroid dysfunction and fluorosis. The effects were observed at fluoride water concentrations highly relevant to community fluoridation programs (0.0, 0.6 ppm and 30 ppm --> please see our response to Guichon et al. regarding the 30 ppm concentration. viewtopic.php?p=4373#p4373).

Once again, we were astonished to find the clear results from Zhao et al. entirely misrepresented.

As it turned out, it was Guichon et al. who were deceiving the public, not FAN who had cited the study correctly.

What Guichon et al. had done:

They took a few sentences from the discussion section – where authors normally cite and discuss relevant work already done on the subject and compare to their own results – and then made it appear as if those sentences were part of the actual conclusions from the study, misleading the reader entirely.


Meanwhile, Guichon and colleagues completely disregarded the real results of the work, ignoring any and all of the authors' conclusions - while accusing someone else of misrepresenting the study!

Results of the study by Zhao et al. (1998)

The landmark study by Zhao et al. brought much new insight regarding the long-observed "fluoride-iodine antagonism". The results showed how fluoride effects such as dental fluorosis and disturbed thyroid hormone metabolism were modulated by iodine.

Considering the fact that mice require much higher fluoride intake to produce similar adverse effects as are seen in humans (Bronckers et al., 2009), it was remarkable that even at "normal" water concentrations of 0.6 ppm, fluoride was seen interfering with thyroid hormone metabolism in mice, reducing T3 while increasing T4 levels - under normal iodine conditions.

The data also showed the influence of thyroid status on dental fluorosis. Depending on iodine intake, the severity of dental fluorosis changed, as described in Table 5:

Image


Further, the data showed that even under fluoride-deficient conditions (0.0 ppm in water), iodine intake could modify the bone deposition of the fluoride inherent in the diet. The higher the iodine intake, the more fluoride was deposited in bone after 150 days - at identical "deficient" fluoride intake.


When we first became aware of the article on the Healthy Debate website, we wrote a short response to Guichon et al. but it was blocked from being accessible to the public.

After contacting Seema Marwaha, Editor-in-Chief, our comment was made visible a few days later (June 2021).

As of September 27, 2021, no reply by Guichon et al. had been received.

On September 3, 2021, a response was posted by Randy Johnson, a self-described "Drinking Water Treatment Consultant" and apparent member of the pro-fluoridation lobby's "rapid-response team".

Comments were then closed by the editor, thus we were unable to reply to Johnson's ill-informed accusations. [We posted our response below - please see thread]. Considering that the vote in Calgary is only a few weeks away, it is disturbing to see such editorial steps being taken, in spite of obvious evidence that science was being suppressed and misrepresented.

As of now, anyone can still see the original article and our response. Zhao's findings can be easily verified by clicking on the link below, or on the hyperlink within the original article. https://healthydebate.ca/2020/06/topic/ ... f-critics/

All six authors should be held accountable for intentionally distorting the findings of the study and misleading Albertans on a vital public health issue.


Wendy Small
PFPC Canada


Bronckers AL, Lyaruu DM, DenBesten PK - "The impact of fluoride on ameloblasts and the mechanisms of enamel fluorosis" J Dent Res 88(10):877-93 (2009)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3318083
"In drinking water, fluoride levels of at least 10-30 ppm are necessary to induce lasting enamel disturbances in rodents, and levels used in most experimental studies are in the range of 25-100 ppm (Shinoda, 1975; Angmar-Månsson et al., 1976; Fejerskov et al., 1979; Ekstrand et al., 1981; Angmar-Månsson and Whitford, 1984; DenBesten, 1986; Kubota et al., 2005)."

NAS - "On Being a Scientist: A Guide to Responsible Conduct in Research" 3rd ed. Committee on Science, Engineering, and Public Policy, National Academy of Science, National Academy of Engineering, and Institute of Medicine of the National Academies, Washington (DC): National Academies Press (US) (2009)
Scientific misconduct: "Intention or gross negligence leading to fabrication of the scientific message".
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ORIGINAL RESPONSE by Wendy Small to the article: "Fluoridation and the ‘sciency’ facts of critics"

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Wendy Small, PFPC Canada June 3, 2021 at 5:17 pm

What is perhaps most disturbing about this opinion piece by Prof. Guichon and her colleagues is the fact that they accuse their opponents of misrepresenting the science, and then proceed to falsely represent one of the most important animal studies in the literature on fluoride effects on thyroid hormone metabolism.

Fortunately, a hyperlink to the study by Zhao et al. (1998) is provided [click on “the coauthors of this study wrote” ]. The reader, therefore, has an immediate opportunity to verify the information presented.

Guichon et al. take a few sentences from the discussion section of the Zhao paper – where authors normally cite and discuss relevant work already done on the subject and compare to their own results – and then make it appear as if those sentences were the actual conclusions by the authors.

Far from it. The actual results from Zhao’s hallmark study show very clearly the “mutually interacting effects” of fluoride and iodine at various doses given, and at concentrations highly relevant for water fluoridation programs. [The “excess fluoride” in this study was 30 ppm. The reader needs to be aware that in rodent studies much higher amounts of fluoride are required to produce similar effects as are observed in humans. For this reason, levels used in most experimental studies are in the range of 25-100 ppm (Bronckers et al., 2009).]

Zhao and his colleagues had published on this matter for over 10 years, confirming their earlier findings from 1988 with this 1998 publication.

Instead of further dismissing the hundreds of studies on the effects of fluoride on thyroid hormones, over 250 of which have appeared in the last 20 years alone – Prof. Guichon and colleagues should honour their position of responsibility as public health officials and accurately inform on the toxicity of fluoride.


REFERENCES:

Bronckers AL, Lyaruu DM, DenBesten PK - "The impact of fluoride on ameloblasts and the mechanisms of enamel fluorosis" J Dent Res 88(10):877-93 (2009)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3318083

Recent Research: 250 Studies from on fluoride and thyroid dysfunction - 2001 to 2021
viewtopic.php?f=7&t=1345
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Response to Wendy Small by Randy Johnson - September 3, 2021

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Randy Johnson September 3, 2021 at 7:58 pm

Yes – Prof. Guichon and her colleagues correctly accuse the anti-fluoridation contingent of “misrepresenting the science”. Your comment is an excellent example of how fluoridation opponents manipulate ‘evidence’ to try and support their opinions. That’s understandable, since the actual scientific evidence does NOT support their opinions.

It is true that in rats, “a 5-fold increase in the dose of fluoride ions is required to achieve comparable human serum fluoride levels. (Fluoride in Drinking Water p. 98)
https://www.nap.edu/download/11571

So, to approximate an optimal level of fluoride (0.7 ppm or mg/L) from CWF, a rat would have to drink water containing 3.5 ppm F–, and rats drinking water containing 20 ppm F– would be equivalent to a human regularly drinking the EPA maximum contaminant level (MCL) of 4 ppm F– (or 4 mg/L).

So, the 30 ppm “excess fluoride” in the 1998 Zhao study was the equivalent of a human drinking water containing 6 mg/L of fluoride – nearly 10 times greater than the optimal concentration in fluoridated water. So, the “levels used in most experimental studies are in the range of 25-100 ppm (Bronckers et al., 2009)” are equivalent to human exposure to fluoride ions at 5 – 20 ppm — that’s 7 – 28 times the recommended level of exposure.

The fact is – none of the studies you referenced have anything to do with demonstrating any alleged thyroid harm from drinking optimally fluoridated water.

Using your “logic” someone could make the case that drinking dihydrogen monoxide was dangerous and should be banned because consuming 7 to 28 times the recommended exposure level will have deadly consequences.
https://www.dhmo.org/facts.html

Contrast the Zhao’s 1998 study with the 2018 Study, An Evaluation of Neurotoxicity Following Fluoride Exposure from Gestational Through Adult Ages in Long-Evans Hooded Rats, designed and conducted by the NTP to evaluate potential harm of fluoride concentrations at levels 2.5 to 5.7 times higher than found in optimally fluoridated water (0.7 ppm). “Long-Evans hooded male rats maintained on a standard diet (20.5 ppm F−) or a low F− diet (3.24 ppm F−) with drinking water exposure to 0, 10, or 20 ppm F− from gestational day 6 through adulthood. … Equivalent human daily water intakes of 1.74 mg F/day for an adult or 0.63–1.23 mg/day for 1 to 14 years of age have been approximated in rodents using drinking water concentrations of 7 to 9 ppm F−. In the current study, the top dose of 20 ppm F− was selected based upon the US Environmental Protection Agency’s Maximum Contaminant Level of 4 ppm [5.7 times higher than optimally fluoridated water] and the conventional wisdom that a 5-fold increase in dose is required to achieve comparable human serum levels.

Conclusions: “At these exposure levels, we observed no exposure-related differences in motor, sensory, or learning and memory performance on running wheel, open-field activity, light/dark place preference, elevated plus maze, pre-pulse startle inhibition, passive avoidance, hot-plate latency, Morris water maze acquisition, probe test, reversal learning, and Y-maze. Serum triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) levels were not altered as a function of 10 or 20 ppm F− in the drinking water. No exposure-related pathology was observed in the heart, liver, kidney, testes, seminal vesicles, or epididymides. Mild inflammation in the prostate gland was observed at 20 ppm F−. No evidence of neuronal death or glial activation was observed in the hippocampus at 20 ppm F−.”
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Response to Randy Johnson by Wendy Small - September 27, 2021

Post by wendy »

Wendy Small September 27, 2021

Thank you for your interesting response, Randy Johnson.

You wrote: (all your comments are in quotation boxes)
Yes – Prof. Guichon and her colleagues correctly accuse the anti-fluoridation contingent of “misrepresenting the science”. Your comment is an excellent example of how fluoridation opponents manipulate ‘evidence’ to try and support their opinions. That’s understandable, since the actual scientific evidence does NOT support their opinions.

You state that my "comment is an excellent example of how fluoridation opponents manipulate 'evidence'."

Please point out exactly where I manipulated 'evidence'? I am somewhat confused by that accusation, and I will readily own up if there is indeed such a manipulation to be found anywhere.

If the actual evidence "does NOT support" our conclusions, please enlighten us and show us where we have erred. Just saying so certainly doesn't make it so.

Meanwhile, let us have a look at some of your statements.
It is true that in rats, “a 5-fold increase in the dose of fluoride ions is required to achieve comparable human serum fluoride levels. (Fluoride in Drinking Water p. 98)
https://www.nap.edu/download/11571

Just to be clear - I did not speak about comparable serum levels, but about comparable EFFECTS, such as dental fluorosis. More about serum levels later.

Your quote is false and does not accurately reflect what is written in the report. The actual statement includes "has been suggested" and "might". Further, you are taking the sentence referring to a study by Dunipace (1995) out of context.

Here is what your source states, in fact (NRC: Fluoride in Water, 2006):
"Evidence suggests that rats require higher chronic exposure than humans to achieve the same plasma and bone fluoride concentrations. It has been suggested that rats might require water concentrations about five times larger than humans to reach the same plasma concentration (Dunipace et al. 1995). For bone, Turner et al. (1992) estimated that “humans incorporate fluoride ~18 times more readily than rats when the rats are on a normal calcium diet. This comparison was also based on water concentrations. In Appendix D, this issue is briefly reviewed. The factor for plasma is uncertain, in part because it could change with age or duration of dose. It might be more appropriate to compare exposures than water concentration. Bone comparisons are also uncertain but appear to support a rat-to-human conversion factor for older rats and humans of at least an order of magnitude."

Not quite the same, is it? Interesting how you left out the things that didn't agree with your version of the truth, such as "at least an order of magnitude", or the comment about total intake (exposure) versus water concentration. More on that below.


Now, to the Dunipace data (1995):

Below is the table from the Dunipace study.

Data shows clearly that in order to achieve a serum level of 2-12 uM fluoride - the range known to produce the condition of dental fluorosis, now affecting 70% of US children and adolescents - rodents required fluoride water concentrations of 15 to 50 ppm. 5 ppm was not enough.

Image



Re: your calculations:
So, to approximate an optimal level of fluoride (0.7 ppm or mg/L) from CWF, a rat would have to drink water containing 3.5 ppm F–, and rats drinking water containing 20 ppm F– would be equivalent to a human regularly drinking the EPA maximum contaminant level (MCL) of 4 ppm F– (or 4 mg/L).

So, the 30 ppm “excess fluoride” in the 1998 Zhao study was the equivalent of a human drinking water containing 6 mg/L of fluoride – nearly 10 times greater than the optimal concentration in fluoridated water. So, the “levels used in most experimental studies are in the range of 25-100 ppm (Bronckers et al., 2009)” are equivalent to human exposure to fluoride ions at 5 – 20 ppm — that’s 7 – 28 times the recommended level of exposure.

Sorry, but that's nonsense.

Once again - the 30 ppm "excess fluoride" concentration produces serum fluoride levels in rodents that are within the range of 2-12 mumol/L, produced in humans by drinking water from fluoridated community water supplies. See Dunipace graph above.

Here is what Bronckers et al. stated in their review:

"Chronic plasma fluoride levels in the range of 2-12 mumol/L, attained by fluoride in drinking water for extended periods of time, induce disturbances in forming enamel in most species, including humans.

The plasma levels in rats also show a linear dose-dependent increase in plasma fluoride levels, from 1 µmol/L (no fluoride) to 9-10 µmol/L, with increases in fluoride in drinking water from 0 to 100 ppm in rats given a low-fluoride diet (DenBesten, 1986).

In drinking water, fluoride levels of at least 10-30 ppm are necessary to induce lasting enamel disturbances in rodents, and levels used in most experimental studies are in the range of 25-100 ppm (Shinoda, 1975; Angmar-Månsson et al., 1976; Fejerskov et al., 1979; Ekstrand et al., 1981; Angmar-Månsson and Whitford, 1984; DenBesten, 1986; Kubota et al., 2005)."

You can further educate yourself on this matter by reading Chapter 2 of the NRC 2006 report that you cited earlier, or any other of the many reviews available on the subject.

The fact is – none of the studies you referenced have anything to do with demonstrating any alleged thyroid harm from drinking optimally fluoridated water.

Again, you are making false statements. Note that I only referenced ONE thyroid study in this context: Zhao et al. (1998).

The significant interactions of fluoride and iodine on thyroid hormones, thyroid weight, radioactive iodine uptake, and dental fluorosis are clearly documented in that paper, even at concentrations BELOW those used for "optimally fluoridated water". If we have misinterpreted the study - as you claim - then point out where we did so.
https://www.sav.sk/journals/endo/full/er0298a.pdf

Besides Zhao et al., there are many other examples, of course. As stated in the original comment, more than 250 papers have been published in the last 20 years documenting fluoride effects on thyroid hormone metabolism. viewtopic.php?f=7&t=1345

Using your “logic” someone could make the case that drinking dihydrogen monoxide was dangerous and should be banned because consuming 7 to 28 times the recommended exposure level will have deadly consequences.
https://www.dhmo.org/facts.html
???

If this is an attempt to be funny - hey, it really isn't, but suit yourself.


Re: your excerpts of the 2018 NTP rodent study:
Contrast the Zhao’s 1998 study with the 2018 Study, An Evaluation of Neurotoxicity Following Fluoride Exposure from Gestational Through Adult Ages in Long-Evans Hooded Rats, designed and conducted by the NTP to evaluate potential harm of fluoride concentrations at levels 2.5 to 5.7 times higher than found in optimally fluoridated water (0.7 ppm). “Long-Evans hooded male rats maintained on a standard diet (20.5 ppm F−) or a low F− diet (3.24 ppm F−) with drinking water exposure to 0, 10, or 20 ppm F− from gestational day 6 through adulthood. … Equivalent human daily water intakes of 1.74 mg F/day for an adult or 0.63–1.23 mg/day for 1 to 14 years of age have been approximated in rodents using drinking water concentrations of 7 to 9 ppm F−. In the current study, the top dose of 20 ppm F− was selected based upon the US Environmental Protection Agency’s Maximum Contaminant Level of 4 ppm [5.7 times higher than optimally fluoridated water] and the conventional wisdom that a 5-fold increase in dose is required to achieve comparable human serum levels.

Conclusions: “At these exposure levels, we observed no exposure-related differences in motor, sensory, or learning and memory performance on running wheel, open-field activity, light/dark place preference, elevated plus maze, pre-pulse startle inhibition, passive avoidance, hot-plate latency, Morris water maze acquisition, probe test, reversal learning, and Y-maze. Serum triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) levels were not altered as a function of 10 or 20 ppm F− in the drinking water. No exposure-related pathology was observed in the heart, liver, kidney, testes, seminal vesicles, or epididymides. Mild inflammation in the prostate gland was observed at 20 ppm F−. No evidence of neuronal death or glial activation was observed in the hippocampus at 20 ppm F−."

1) It should be quite obvious to you by now - again, see Dunipace graph above - that the NTP failed to apply the data appropriately.

2) Re: TSH, T3, T4, Long-Evans rats, "standard" diet, water concentrations:

Please note that we have publicly addressed the many shortcomings and false conclusions of the NTP study in great detail on our website, as well as in our submission to the US National Academy of Sciences from November 2020.
Again, if there is ANYTHING in those documents that you believe to be incorrect, please provide the evidence and we will promptly correct it.
[You may send any correspondence to info2 AT poisonfluoride.com, and we will post it here.]


Meanwhile, please refrain from spreading false information on fluoridation and fluoride toxicity.

Wendy Small
PFPC Canada


National Research Council - Fluoride in Drinking Water: A Scientific Review of EPA's Standards (2006)
https://www.nap.edu/download/11571
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