There are fundamental differences in physiology between animals and humans. Differences between species at anatomical, physiological, cellular, molecular and genetic levels mean that drugs and other substances can and often do cause different responses in different species, rendering it inaccurate to extrapolate data to humans in certain experiments.

Fluoride is double edged sword, the concentration of fluoride at which it is consumed is vital, 1 ppm of fluoride or less than 1 ppm is not harmful to the human body, rather it helps in caries prevention. Dental fluorosis is only seen when the concentration goes beyond 1.5 ppm and skeletal fluorosis beyond 3 ppm of fluoride. Water fluoridation aims to regulate the upward adjustment till 1 ppm. Significant public health achievement is seen in reduction of dental caries with use of optimal level of fluorides.

More and more studies should be encouraged to find systemic effects of fluorides at 1 ppm.

Dear Amrit,

Please cite the references for your statements that:

Best regards,

Michael Lusk

In Zhang's study, the concentrations used were 50 mg 100 mg and 150 mg NaF equivalent to 221, 450 and 675 PPM of fluoride, when the dose used in water fluoridation is around 1 PPM.

Dear José,

Apparently you refer to Zhang G. et al. (2017) as distinct from Zhang Y. et al. (2014). However, neither of those studies considers dental fluorosis.

My question to Amrit remains unanswered.

Kind regards,

Michael Lusk

I agree, none of the articles talks about fluorosis, but the original question is: why if it has been shown that fluoride is toxic, it has not been banned, my answer is yes, Fluoride is toxic, but for produce the effects that are mentioned in the articles on which Dr. Pain is based, the doses are much higher than those used to prevent the caries process.

In some parts of my country, drinking water contains cyanide, but the doses are lower than those that produce toxic effects.

Dear José, 1. Now we come to the crux: the toxic dose.

2. Let us begin with the mildest matter: dental fluorosis. Notwithstanding the enviable benefit of naturally low fluoride concentrations in most public water supplies, the Australian population suffers a substantial incidence of dental fluorosis. According to the New South Wales Child Dental Health Survey 2007 (“NSW Report”, www.health.nsw.gov.au/oralhealth/Publications/Child-Dental-Survey-2007.pdf), a total of 3.8% of 11‑12‑year old children in fluoridated areas of the State demonstrated "severe" (3.3%) or "very severe" (0.5%) dental fluorosis. By comparison, a total of 0.2% of 11‑12‑year old children in unfluoridated areas of the State demonstrated "severe" (0.2%) dental fluorosis, with substantially none demonstrating "very severe" (0.0%) dental fluorosis.

3. It is apparent that Australian governments created the problem of endemic dental fluorosis by requiring artificial fluoridation of public water supplies such that the concentration of fluoride in drinking water is increased to the purportedly "optimal" range of 0.6 to 1.1 mg/L, depending on climate: https://www.nhmrc.gov.au/_files_nhmrc/file/publications/17667_nhmrc_-_public_statement-web.pdf.

4. Responsible governments seek to avoid such adverse medical effects by defining a tolerable upper intake level (“UL”) for known toxic contaminants. The UL for a toxic contaminant normally is defined as the biologically tolerable upper intake level.

5. In the past, the Australian government acted somewhat responsibly in this respect in relation to fluoride. The Australian UL for fluoride in relation to 4-8 year old children originally was set at 2.2 mg/day. However, in apparently belated response to the rising incidence of dental fluorosis as documented in the NSW Report, the Australian government reacted not by enforcing its UL, but instead by increasing the UL. in November 2017 the CEO of Australia's National Health and Medical Research Council ("NHMRC"), Prof. Anne Kelso (https://theconversation.com/profiles/anne-kelso-1104), purported to approve guidelines doubling the UL for fluoride in relation to 4‑8‑year old children from 2.2 mg per day to 4.4 mg per day. Not coincidentally, also in November 2017 NHMRC issued its 2017 Public Statement - Water Fluoridation and Public Health in Australia (link provided at paragraph 3, above)

6. In order to place Prof. Kelso's action in international perspective, the Australian UL for fluoride now stands at 200% of the U.S. UL for fluoride, as defined by the U.S. National Academies of Science. It should be obvious to everyone, with or without, advanced academic degrees, that Australian children did not in November 2017 suddenly become more tolerant towards fluoride toxicity. In my legal opinion, Prof. Kelso's action in approving the relevant guidelines was criminally negligent. In my view, Prof. Kelso and NHMRC are complicit in a conspiracy of Australia's federal and State governments to poison the Australian population.

7. It should be clear from the foregoing text that Amrit is wrong in claiming that "[d]ental fluorosis is only seen when the concentration [of fluoride] goes beyond 1.5 ppm". As the NSW Report indicates, fluoridation of drinking water to attain the purportedly "optimal" range of 0.6 - 1.1 ppm has sufficed to cause endemic dental fluorosis in the Australian population.

8. Let us proceed to the more serious matter of other adverse health effects of fluoride. You note that the animal studies referred to in Geoff's question considered fluoride dosages "much higher" than those used for the purported purpose of preventing dental caries were used. You thereby suggest (but do not actually state) that population-level fluoride treatment at the poorly controlled dosage used by Australian governments for the purported purpose of preventing dental caries would be medically safe. Perhaps you preferred merely to suggest this unwarranted conclusion because proof of harm at a high concentration obviously does not imply safety at a lower concentration. Naturally you are at liberty to cite evidence of safety, in case that is your position.

9. Having regard to e.g. Bashash et al. (2017), please clarify your position. Do you claim, for example, that treatment with fluoridated drinking water containing 1.0 ppm fluoride does not:

(a) reduce cognitive function in children?

(b) impair kidney function in aged persons?

Kind regards, Michael Lusk