Guest post: Fluoridation

After SB’s post about Vaccination I received a guest submission about fluoridation.

Hi team

Really impressed about SB post about vaccination. It is so hard to find any unemotional look at the data/facts. Both sides rely heavily on the emotions/guilt/worry/fear deal.

Please find attached a guest post about water fluoridation. The TL;DR summary is that I stated to write a submission about how I don’t support water fluoridation. However as I went through all the points against it, I found them to be half truths. So have changed my mind and now support it. But the difference between un-fluoridated and fluoridated is becoming less as fluoride becomes more common in our environment. So at some time in the future we will no longer need it. Also there are very serious risks of babies being bottle feed obtaining to much fluoride and having health effects.

Have not seen real rebuttals of the anti-fluoride people, so hence this doc. The irony is that an anti-fluoride person drinking a cup of tea gets more fluoride from the tea, than the water! Offered it to the MSM but no one would take it…..

If you tell me the day it is going to be published I can be online for any comments (can’t be Sat or Sun as out for weekend).



Water fluoridation

A seminal moment occurred to me while at university. And like many such pivotal moments it occurred completely unexpectantly. One day while striding down the university corridor in my tall black leader boots, ripped jeans, long trenchcoat and long hair I got trapped behind to old lecturers slowly ambling down the passage to tea. They were really old, at least 30! One turned to the other and said “ the problem with the system is that by the time we get student to PhD or higher and they can know really start to question things, they are so indoctrinated in the way things are, that they are not willing/able to question things.” This has stayed with me every since as a warning to always be open minded and question the commonly held truisms.

My journey with fluoride begin like most with believing that is was great. But then doing some reading some years ago changed to thinking it was at best a scam and worst a poison. However I didn’t care to much as we were not on town supply, so it was a moot point. Recently Hamilton re-examined its views on fluoridation and as such I went to write a brief facebook post about how they should get ride of it. In this process I realized my belief was based upon some figures I had read, that being dyslexic I had got wrong by a factor of 10. Thus I needed to reexamine by beliefs once again.

This time I seriously looked at every claim the anti-fluoride peoples made, and considered their validity. Most, but not all, fall under the title of half truth or selective data picking. That is there is some truth in their statements but they are not telling the whole picture. These are quickly dealt with before getting onto the arguments, which ironically are not the major ones but forward, that have substance.  

But before that some facts around where you get a majority of your fluoride from. The answer is tea, if you drink cups of tea you are consuming high levels of fluoride! Some plants are mineral accumulators. They activity concentrate up selected metals intro their plant tissues, this can be theoretically used to concentrate up metals for mining or for remediation of heavy metal contaminated sites. The tea plant, Camellia sinensis is a fluoride accumulator. The older the leaves the more fluoride they contain. Thus the lower quality teas which are made from old leaves contains high fluoride levels. For example a Chinese study showed that tea made from pre-cut black tea bags had a whopping 1.5 – 6.0 mg/L[i]. This compares with fluoridated water of 0.7mg/L, that the tea adds twice to nearly 10 times fluoride than the water.

Green tea has slightly less being 0.8 – 2.0[ii] (Portuguese study) likely due to the younger leaves used in green tea.

The levels of fluoride in tea will depend upon the fluoride levels in the soil as well as the leaf age. Currently no resent research has been done in NZ on the fluoride levels in our common tea bags. But given that NZ tea is typically black and comes in pre-packaged tea bags it is likely to contain high levels of fluoride.

Thus the anti-fluoride people should also be campaigning against tea consumption. But they are not, which makes one question their scientific understanding.

Lastly before delving into the claims, you should be aware that municipal water supplies levels are recommended to be fluoridated with 0.7mg/L of fluoride and secondly fluorosis is a serious condition of teeth degradation caused by excess fluoride in the diet

Half truths.

Fluoride is poisons at low doses. Yeap, so is selenium. Yet we accept selenium needs to be supplemented to have it in the NZ diet (well at least most farmers do). The WHO has set an upper threshold of daily intake at 2 mg for child and 4 mg for adults. So that equates to 3 – 16 cups of tea for an adult depending on the fluoride levels in your tea bags.

European countries do not fluoridate water supplies. This is correct. However what is not said is that European counties decided to fluoride their populations via salt. Thus their salt not only contains iodine, it also contains fluoride. Thus the population still (supposedly) obtains intake of fluoride. From an ethical point of view is a better solution that mass water dosing as it allows people to opt out very easily, just like you can purchase non iodized salt. It is noted that those who use the “European s don’t fluoridate” argument are not encouraging salt fluoridation.

An area (typically somewhere in China)has low fluoride in water (and population has fluorosis of the teeth.. Again this statement is correct, but again is not the whole story. Apart from fluoride in water fluoride ingestion occurs via two mechanisms, drinking tea and breathing air contaminated by burning high fluoride coal. Thus these areas are exposed to fluoride via these three mechanisms. Thus fluoride intake in water is likely to be the smaller part of their daily intake.

Already in our water supply. Yes this is true, but again a half truth. There is detectable fluoride in most north island water, due to the igneous rocks / volcanic activity. However the real question is the fluoride at high enough levels to help prevent decay? The answer is a resounding no. The levels are typically a number of orders of magnitude lower than the levels needed to help prevent tooth decay.

Fluoride injected into the water is a waste product from the chemical industry. Is not food grade and has low levels of fluoride. Thu implying it contains lots of other nasty chemicals. Yet again a half truth. Yes hexafluorosilicic acid is a waste product from phosphate fertilizer manufacturing. Last time I checked on selling a waste product was called up-cycling or re-cycling a clever business practice and reduces waste. Therefore you would think this would be encouraged given that most anti-fluoride people are “green” in their outlook!

The food grade is a rather red herring. You can purchase “high quality” expensive crystalline sodium fluoride which apart from being expensive is highly refined and pure. Thus this highly refined and highly expensive product is used as a laboratory reference standard. But a better question is the level of contaminates in the fluoride high enough to be a problem. The short answer is no. The longer explanation is below.

Firstly there are low levels of fluoride in hexafluorosilicic acid. If you re-read the chemical name, instead of glossing over it, you see that there is silica (silic) in the material. In fact hexafluorosilicic contains a bunch of hydrogen, oxygen and a silicon atom for every fluoride atom. When this is mixed into water you get fluoride ion in solution (what you need), plus “waste” products of silicon dioxide (white sand / glass) and some hydrogen ions (things that make up water). Therefore even though fluoride makes up approximately only 25% of hexafluorosilicic acid the other materials are not nasty. They are inert and commonly found in everyday life.

Secondly there is “contamination” of hexafluorosilicic acid with other heavy metals and contaminants. This is hard to refute given the nebulous accusation. However searching finds a site stating that arsenic can reach levels of 1.66ppb[iii] and safe water cut off is 0.01ppm. This looks bad, but the units are not the same, catching out “young players”, re-writing so units are the same, arsenic from hexafluorosilicic acid gives water contamination of 0.00166 with cut off of 0.01ppm. Remember this is the “worst case” that the anti fluoride people have come up with. But is still under the limit by a factor of 10.

What is more disconcerting is that the Waikato river is high in arsenic, mainly from the geothermal power stations dumping “clean” hydrothermal ground water into the river. The levels are consistently 0.03 ppm, that is 3 times over the “safe” limit[iv]. This arsenic is not removed for any of the towns/cities that take water from the Waikato for drinking, including Hamilton and Auckland. Yet anti-fluoride people don’t bring this issue up!

Lastly lead contamination is also raised as being a problem[v]. The lead in the pipes apparently can react with the combination of chlorine and fluoride to raise levels higher than just the chlorine itself. As no data is presented it is very difficult to assess what his means. Clearly a 0.001% increase is no important but a 10% could be. Given that we use lead in the solder that joins pipes together NZ health authorities already recommend flushing the first 30 seconds of water down the drain, before using it for cooking / drinking purposes. Especially after the water has been sitting in the pipes overnight or while at work.

Needs to touch the teeth’s surface to work and drinking water does not touch your teeth as you drink it. To refute this we first we need to understand how the fluoride improves teeth quality. The fluoride is “swapped” for hydroxyl in the crystal. hydroxyl groups are a oxygen and hydrogen together (OH). The swapping out of this water/hydrogen molecule with fluoride ion (F-) makes the crystal structure of the apatite much stronger / harder. Thus the enamel is stronger / harder. Thus resisting better the acid etching of the bacteria, confirming a lifetime of better teeth.

There are two schools of thought as to how this occurs. The first and less popular is that children’s first and adult teeth develop while still contained within the gums/jaw as the apatite crystals form to produce the outside tooth enamel. (Fluorosis occurs when to many of the hydroxyl groups swap, and the crystal then become brittle and breaks down. This is clearly bad and is the clinical signs of to much fluoride.)

The second is that the fluoride is absorbed into the blood and then re-enters the mouth as part of the salvia. The reaction, mentioned above then occurs in the mouth.

Thus fluoride does not need to touch children’s teeth to provide the benefit

Where does the statement come from then about surface application of fluoride? I could not track down the original research / first statement, which makes me wonder if it is one of those myths that repeated enough, becomes fact. However I suspect that topical applications of fluoride onto adult teeth strengthens them via the ion exchange mentioned above. Hence toothpaste contains fluoride and dentists paint your teeth with fluoride.

Children’s lower IQ with fluoride. The argument is studies have shown high levels of fluoride are bad for IQ / development. Firstly there are significant issues with measuring IQ (bias etc.) so a large amount of tests/studies and data is needed before a statement around IQ can be made. There are only a small number of students and none of these studies had levels even close to the typical 0-7-1.0 mg / L range. There were all 2.0 mg/L or more, and most had much higher fluoride levels[vi]. Thus IQ lowering only occurs at very high fluoride levels.

Now we have dealt with the simple issues, now onto the ones that require some more thought.

Fluorosis occurs at epidemic levels in fluoridated water supplies.

Fluorosis in this context is enamel defects in teeth. Paradoxically significant enamel defects increase the risk of tooth decay. To investigate this further the two latest NZ studies published 2005[vii] and 2008[viii] were analyzed.

Fluoridated water areas the percentage of enamel defects was 52%, and 41.4%. This is a massive number, indicating that approximately half the children in fluoridated areas had defects, thus seemingly supporting the statement about epidemic levels. However compare this to the non fluoridated areas, of 48% and 32.3% suddenly it appears that not having fluoride in the water also results in enamel defects.

Further investigations revel that enamel defects come in three types, to start with demarcated then diffuse opacities and lastly hypoplasis. I learnt something new that ideal enamel on teeth should actually be translucent. What I call normal, which is white teeth at the end, is technically an enamel defect called demarcated opacity! The diffuse opacities are white lines or white patches on teeth. And lastly hypoplasis is what I would call a tooth defect, either looking like flakes or pits in the enamel surface.

What is interesting is that photos of the second tier defect of diffuse opacity teeth were shown to US fourth year dentistry students they actually saw then as positive. There is so much media portrayal of gleaming white teeth that these opacities are more like the medias presentation of teeth, than normal teeth!

Turns out that across nearly all studies (n=6) done in NZ since 1980 have shown that there is no statistical difference between the fluoridated and non fluoridated groups for the lowest level defect of demarcated opacities. This also is true for the hypoplasis defects which may cause tooth decay. Thus the only difference is that there are more “white” teeth with the diffuse opacities in the fluoridated groups. This increase is approximately 15% and is statistically significant. Thus although this is an issue that need monitoring, there is no cause for concern.


Another point is that there are additional risk factors for fluorosis. In the US where fluoride levels are naturally high the risk of fluorosis increases with the following risk factors:

  • Not breast feeding till 6 months, the longer breast feeding, the lower the risk.
  • Fluoridated toothpaste 2x day at young age and not spitting it out
  • Fluoride pills/supplements
  • Fluoridated mouthwash

Natural fluoride is absorbed less than industrial fluoride.

When I first heard of this statement I gave it considerable credence. This is because there is a big difference in absorption between minerals found bound to proteins in plants and animals, compared to laboratory based manufactured minerals. For example zinc oxides, sometimes found in supplements cannot be absorbed or used by the human body. Zinc salts (typically zinc sulphate, zinc chloride) can be absorbed but are not used as much as zinc chelates (zinc bound to protein).

However fluoride does not show this trait. Sodium fluoride (NaF) was found to be no different to amine fluoride (fluoride bound to protein), when it come to fluoride levels in saliva or plaque[ix].

Furthermore a study specifically looked at for differences in hard/soft water and naturally fluoridated water and vs artificial fluoridation found no statistical difference between the two groups[x].

That bottle feed newborn babies can overdose on water fluoride. Finally we get to an objection that has scientific merit and ethical issues. Excess fluoride is possible due to the low body weigh coupled with baby taking in relatively large volumes of water. The US EPA recommends 0.06 mg intake per kg of body weight per day. Given the average birth weight in western countries is 3.4 kg, this gives an approximate intake of 0.2 mg/day.

Where as the US national Academy of Science recommend intake is lower being 0.01mg/day with a tolerable upper intake of 0.7 mg/day[xi].

Breast milk which should always be taken as the gold standard has only 0.004 – 0.015 mg / L[xii]. And given an average baby (whatever that is) has in intake of 750ml this results in an intake of approximately the recommended daily intake.

Not much work has been done in fluoride levels in formula. Low fluoride areas have approximately 0.1 mg / L in milk and in higher areas this can increase to 0.4 mg / L without the cows showing signs of fluorosis. So initial data indicates cow formula is higher in fluoride by a factor of 10. This coupled with fluoridated drinking water of 0.7 mg/L means an “average” baby on formula would be getting 0.6 mg a day, which is right on the cusp of tolerable upper intake of 0.7 mg/day and approximately 3 times the EPA recommended intake.

So even though fluoride levels in water and cows formula combined are higher than the recommended intake they are still lower than the maximum safe intake levels. However there is not much room for error. So factors like low birth weight coupled with high feed intake (aka hungry babies), the risk of fluorosis in my opinion is significant enough that I would purchase bottled water for any of my children if they were not breast feed for first 6 months.

Further complicating the ethics is that people in low social economic groups are thought to gain the most benefit from fluoridation. However it is these same groups that have low breast feeding rates/duration and also have higher risks of low birth weight babies. Thus there is a real concern here that the people we might be trying to help, are in fact put at risk.

Libertarian argument.

From a libertarian perspective mass dosing without each persons consent is not appropriate. It comes down to the old age argument of one verses the many. The reason I do not put significant weight to this argument, although I would consider myself of libertarian persuasion, is that as an adult is relativity simple to opt out of the fluoridation. There are many options to have fluoride free water if your municipal supply has fluoridation. You can collect own drinking water from your own roof. You can purchase bottled water for drinking and cooking purposes. You likely know someone you work with who either lives in the country or in another town which doesn’t have fluoride in the water, so they can bring in drinking water for you. There are many solutions if you don’t want to partake, as most of the water in the house goes back down the drain, water actually consumed as part of drinking or cooking is a very small proportion of the water flow into a property.

Fluoridization has diminishing returns.

To investigate this, we should return to the original research, then the most up to date we have, before asking why things may have changed. One of the studies undertaken in the early days of fluoride is summarized in figure 2. This illustrates dramatic drop in the average number of diseased teeth as the fluoride level drops from very low to approximately 1 mg/L. When fluoride was introduced to towns in these states there was a drop of between 59.4 to 70.8 percent drop in the number of decayed, missing and filled teeth. Clearly this was a success.

Figure 2. Graph of number of disease teeth with changes in fluoride level[xiii].

However things have changed in the last 70 years! Therefore are these results comparable with current New Zealand or Australian results?

The three studies undertaken since year 2000 show that if we only look at the number of teeth with decay, there is a drop of 10% in the difference between fluoridated and non fluoridated. So clearly this is not as bigger drop as the US originals. However this doesn’t tell the complete story. There is a metric called DMFS for Decayed, Missing, Filled Surfaces. This counts up the number of teeth surfaces (fours side and top for back teeth) that have been impacted. For example a small filling on one surface is clearly less impacting than a tooth that has had fillings on all four sides. This study found a 58% drop in DMFS score for percent teeth if the child had lived in fluoridated water continuously until they were 9 years old[xiv].

Using the DMFS metric another resent found a significant drop of 31% for deciduous (baby) teeth and 41% for permanent teeth for 12 year olds[xv]. Interestingly for kids 9.5 years of age, there was not a significant difference in number of teeth with fillings for permanent teeth, although there was for deciduous teeth. This could have been the small number of permanent teeth that come through for 9.5 year olds. Or the authors noted that most of the molars that had emerged had become fissure sealed, thus reducing molar decay[xvi].

Thus the effect of fluoridation would appear to be less than the effect initially discovered nearly a century ago. However there does still appear to be a significant positive effect of preventing teeth decay.

Others sources of fluoride

As fluoride has become more common in tooth care products, and topical applications at dentist etc, it appears that the difference between fluoridated and non fluoridated populations is decreasing. Also as fluoride used in water fluoridation comes as a waste product from phosphate fertilizer processing, it is unsurprising that farms in NZ (and other countries) have found a build up of fluoride in the pasture and dirt. Thus food / animals grown on these pastures will have higher fluoride levels than before.

Hence overall children in non-fluoridated areas are obtaining significantly more fluoride through dietary and other sources, than 50 years ago when fluoridation was discovered. Thus the difference between fluoridated and non-fluoridated may continue to close as the years progress.

In conclusion

Most of the arguments against fluoride are half truths. Thus upon closer inspection they do not present a valid argument against fluoridation. However there are risks associated with fluoridation for bottle feed new borns. This risk increases if their teeth are brushed with fluoridated toothpaste in first 2 years of life.

There is still a benefit for fluoridation, but the benefit is reduced compared to the original research. Therefore it is possible that in the future there may not be a benefit in fluoridation. However sound solid rational debate is missing. Most arguments are irrational and emotional. The pro-fluoride people, basically say we need it, it works, now stop asking questions. And the anti-fluoride people are not open to debate on data and science. Both sides need to see the opposite side of the debate having legitimacy and come to the table with rational data backing up the arguments.


[i] Cao J, Zhao Y, Li Y, Deng HJ, Yi J, Liu JW. Fluoride levels in various black tea commodities: measurement and safety evaluation. Food Chem Toxicol. 2006 Jul;44(7):1131-7. Epub 2006 Feb 28.

[ii] Reto M, Figueira ME, Filipe HM, Almeida CM. Chemical composition of green tea (Camellia sinensis) infusions commercialized in Portugal. Plant Foods Hum Nutr. 2007 Dec;62(4):139-44. Epub 2007 Sep 27.

[iii] Fluoride Altert.Org (2013) Fluoridation chemicals. Downloaded on 13th November 2013 from

[iv] Te Ara – The Encyclopedia of New Zealand (2013) Arsenic in the Waikato River. Downloaded 13th November 2013, from:

[v] Fluoride Altert.Org (2013) Fluoridation chemicals. Downloaded on 13th November 2013 from

[vi] National Research Council. Fluoride in Drinking Water. A Scientific Review of EPA’s Standards. Washington, DC, USA: National Academy of Sciences; 2006 pg 205-223.

[vii] Mackay, T.D. and Thomson, W.M. (2005) Enamel defects and dental caries among Southland children. New Zealand Dental Journal. 101:2 35-43

[viii] Schluter, P., Kanagaratnam, S., Durward, C. and Mahood, R. (2008) Prevalence of enamel defects and dental caries among 9-year-old Auckland children. New Zealand Dental Journal 104:4 145-52.

[ix] Naumova, E.A., Kuehnl, P., Hertenstein, P., Markovic, L., Jordan, R.A,, Gaengler, P. and Arnold WH. (2012) Fluoride bioavailability in saliva and plaque.   BioMed Central Oral Health. 9;12 3. doi: 10.1186/1472-6831-12-3.

[x] Maguire, A., Zohouri, F.V., Mathers, J.C., Steen, I.N., Hindmarch, P.N. and Moynihan, P.J. (2005) Bioavailability of fluoride in drinking water: a human experimental study. Journal of Dental Research. 84:11 989-93

[xi] Denbesten P, Li W (2011) Chronic fluoride toxicity: dental fluorosis. Monograph Oral Science. 2011;22:81-96. doi: 10.1159/000327028. Epub 2011 Jun 23

[xii] Jensen, R., (ed) 1995, Handbook of Milk Composition, Academic Press, Pg 649

[xiii] Wohl, M. and Goodhart, R. (ed), (1970) Modern Nutrition in Health and Disease. Lea and Febiger. Philadelphia. pg 638

[xiv] Mackay, T.D. and Thomson, W.M. (2005) Enamel defects and dental caries among Southland children. New Zealand Dental Journal. 101:2 35-43

[xv] Lee, P. and Dennison, P. (2005) Water fluoridation and dental caries in 5- and 12-year-old children from Canterbury and Wellington. New Zealand Dental Journal. 100:1 10-5.

[xvi] Schluter, P., Kanagaratnam, S., Durward, C. and Mahood, R. (2008) Prevalence of enamel defects and dental caries among 9-year-old Auckland children. New Zealand Dental Journal 104:4 145-52

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