Prof Peter Gluckman published ‘What is in the water?’ on 12 June 2013. Below is a critique of the points made by him. We would welcome an open public discussion with Prof Gluckman in the interests of a fully informed society on fluoridation.
Office of the Prime Minister’s Chief Science Advisor (OPMCSA):
In recent weeks we have seen a revival of the water fluoridation “debate”. Perhaps the question we need to ask is “what is the debate really about?”
The science of fluoride in water is effectively settled. It has been one of the most thoroughly worked questions in public health science over some decades. There is a voluminous scientific and lay literature that needs to be considered.
Fluoride Free NZ response: Read a summary of the York Review (2000) for a discussion on the statement that the science is effectively settled. Chair of the Advisory Group, Prof Trevor Sheldon MSc, MSc, DSc, FMedSci. clarified a number of points surrounding the science.
“The review did not show water fluoridation to be safe. The quality of the research was too poor to establish with confidence whether or not there are potentially important adverse effects in addition to the high levels of fluorosis. The report recommended that more research was needed”.
“The review team was surprised that in spite of the large number of studies carried out over several decades there is a dearth of reliable evidence with which to inform policy. Until high quality studies are undertaken providing more definite evidence, there will continue to be legitimate scientific controversy over the likely effects and costs of water fluoridation.”
Prof Gluckman’s response is in contradiction with the conclusions of the York Review.
What can be added to this is the recent admission from Prof Skegg in an email to Prof Gluckman 0n 5 April 2014, that the literature on the potential risks are ‘vast and quite complex’. For Gluckman to dismiss this ‘vast’ work on the potential risks with the standard pro-fluoride one liner that the ‘science of fluoride in water is effectively settled’ seems hard to believe at best.
5 April 2014 – Prof Skegg emails Prof Gluckman
“As you will see below, however, (name withheld) is questioning the feasibility of our approach. As you know, I have always had concerns that (quote withheld) – whereas the benefits of fluoridation can be summarised succinctly – the literature on potential risks is vast and quite complex. I can understand why any reputable scientist would be reluctant to put their name to a report if they have not had time to take a first-hand look at the evidence. Also I do not know whether (name withheld) has familiarity with epidemiological concepts and methodology.”
OPMCSA:
There is no doubt that the presence of low amounts of fluoride in water (either naturally occurring or adjusted to between 0.7 and 1 mg/litre) reduces the incidence of dental caries and this is even in advanced economies where dental hygiene has been much improved and where fluoride toothpastes are available. In some countries, fluoride need not be added to the water supply because their geology naturally provides water with fluoride in at least these concentrations. But for some decades, in countries such as New Zealand, where fluoride levels are very low in natural water, fluoride has been added to the water supply.
Notably, both the very young and the old benefit from fluoride in the water supply. They develop fewer dental caries and thus have a significant reduction in the downstream effects such as the need for invasive dental surgery associated with problematic dental status. As in all populations the burden of poor dental health is considerably greater for those in less advantaged socioeconomic conditions and it is this population that benefits most from water fluoridation.
Fluoride Free NZ response:
There is little evidence that fluoridated water reduces dental decay. The Ministry of Health have been claiming the fluoridation reduces dental decay by 40%. Under the Official Information Act, the MOH admitted that they got this figure from the 2009 Oral Health Survey.
However, within the publication itself it states:
“It is important to note that it was not one of the objectives of the 2009 NZOHS to compare the oral health status of people by fluoridation status, and therefore the survey cannot be taken as a fluoridation study. The following results are a snapshot in time and constitute an ecological analysis based on current place of residence. As such they do not take into account lifetime exposure to fluoridated and non-fluoridated water supplies. Individuals who currently live in fluoridated areas may have spent time in non-fluoridated areas, and the reverse is also true. Furthermore, there may be other confounding factors that haven’t been taken into account.” Read more about the 2009 Oral Health survey here.
For more analysis on the New Zealand Dental studies click here.
OPMCSA:
In other areas of the world, natural levels of fluoride in water can reach well above 4 mg/litre – this level is considered by authorities to be the level at which water is still determined to be perfectly safe for human consumption. It is absolutely clear that at doses used in New Zealand to adjust the natural level to a level consistent with beneficial health effects (0.7-1.0mg/litre), there is no health risk from fluoride in the water.
Fluoride Free NZ response to be updated soon
OPMCSA:
Like any agent, including salt, sugar and water itself, if you eat or drink enough it can become toxic. At the doses used in New Zealand water, however, one would in all likelihood become very ill or succumb to water intoxication before any toxic effect of fluoride was discernible.
Fluoride Free NZ response:
This comment is generally phrased in this way: You would have to drink 5,000 glasses of water to die from fluoride poisoning (so fluoridation is perfectly safe).
This refers to the acute toxicity of fluoride, listed above. It is irrelevant to fluoridation, where the risk is long term exposure and accumulation in the body.
This can be compared with the Minimata Bay disaster in Japan, in the 1950s. No one could have eaten enough fish to drop dead instantly from methyl mercury poisoning, but 30 years of low level exposure and accumulation in the body made the inhabitants very ill, and some died.
Anyone who makes the statement that you would have to drink 5,000 glasses of water to die from fluoride poisoning, is misleading the public.
OPMCSA:
However there is one side effect of fluoride that is found even at this low level of fluoride in the water supply; in a portion of the population, it causes minimal white mottling of the enamel of the permanent teeth. This is very rarely discernible and is definitely not the severe fluorosis that is so often pictured on websites of those opposed to fluoridation of the public water supply. The latter is associated with drinking water with very high naturally occurring levels of fluoride (more than ten times levels in New Zealand water after fluoridation) or from other sources of high fluoride – for example that found in some forms of black tea, generally in parts of Asia. The exposures needed are chronic exposures at levels many times that in our water supply.
Fluoride Free NZ response to be updated soon
OPMCSA:
So why is there any issue at all? There are at least two primary questions on which public debate seems to be hinged.
The first issue is an inherent challenge for any public health intervention: How to balance the common good of a population-based intervention with individual rights? This is primarily a question of societal values not science. Indeed, the balance between doing good (reducing caries) and not doing significant harm (minimal dental mottling) is scientifically clear. Thus in some ways any remaining debate has analogies to the immunization situation and to the imposition of regulations such as those requiring the wearing of seat belts. However whether to apply the science-based knowledge in this equation is a question of public health ethics and societal values.
Fluoride Free NZ response. Prof Gluckman is attempting to muddy the waters by introducing parallel’s with immunisation and wearing seatbelts. Clearly there are still unanswered questions regarding fluoride’s safety and effectiveness.
OPMCSA:
The second issue is yet another values debate: Can food be used as a medium for delivering a public heath intervention? Is it OK for public water to be manipulated for an additional health benefit or for a potentially medicinal purpose? As it happens we already do so with iodine – our salt is iodised to prevent the developmental delay (cretinism) and goiters (big thyroid glands) associated with iodine deficiency and which was so common in New Zealand 100 years ago. There is no scientific issue here -it is purely an issue of values.
Fluoride Free NZ response to be updated soon
OPMCSA:
But because both such questions are values-based, for many people they are difficult to discuss. As with other issues where science and values are seen to converge – such as climate change – it is often easier for those seeking to advance values-based concerns to make the science sound scary or more uncertain than it really is. Indeed, it becomes a tactic amongst those who become passionate about their cause. Because biology and medicine are complex, studies can be difficult to put in perspective and odd results can be given undue weight. I have discussed this problem extensively elsewhere.
Fluoride Free NZ response to be updated soon
OPMCSA:
The fluoride debate is based in no small part on numerous examples of inappropriate extrapolation from what happens at hugely higher doses of fluoridation, combined with what is frankly scaremongering. Further, because the way one looks for side effects following population interventions requires particular epidemiological approaches, the language of evidence-based medicine can be confusing to the non-expert and easily exploited.
Fluoride Free NZ response to be updated soon
OPMCSA:
With regard to fluoride, there have been genuine concerns raised regarding risks of bone disease, thyroid disease, brain disease and cancer. While these issues have been settled, they continue to be emphasized by those who oppose fluoride. Some of this continued emphasis is based on inappropriate interpretations of studies in rats or from humans who have fluoride poisoning or live in areas where there are extremely high concentrations of fluoride naturally occurring in the water or diet. Obviously the medical and public health science community has put a lot of effort into being sure that this is not the case at the doses being used to adjust natural levels in water. Safety has been the subject of major assessments by many health authorities in Western countries. It is clear that there is no risk of such disorders at the doses of fluoride being used and extensive epidemiological surveys have repeatedly confirmed this to be the case.
Fluoride Free NZ response to be updated soon
OPMCSA:
So why does this concern continue? The misuse or inappropriate and alarmist use of science is a classic example of science being a proxy for values debates. Others, who have a more skeptical view of the medical-scientific sector, have seen this as some bizarre form of conspiracy. Alternatively, it could be that it simply provides a platform for people looking for a cause to fight because of their personal ideology.
Fluoride Free NZ response: The discern continues because there has been no public debate. The council’s and government do not want to discuss the topic of fluoridation. The ramifications for them being incorrect on the fluoridation issue are wide ranging and they cannot be seen to be wrong.
OPMCSA:
The scientific basis for stating that fluoride in water (at the concentrations recommended) is a safe and very effective approach to improving dental health is clear.
See the first Fluoride Free NZ response up the page.
OPMCSA:
Where there is debate, it is with the values-based issues, even though these can be overstated. Sadly, rather than having dialogue on such values issues which is a proper discourse for society, the debate has been hijacked by a misinterpretation of science. Such values debates are critical for a healthy democracy, but they cannot proceed usefully if the debate is shifted inappropriately to another domain.
Fluoride Free NZ response:
OPMCSA:
The Ministry of Health and its expert dental, public health and scientific advisors have been well positioned to opine on the science. Indeed their conclusions are in accord with other major scientific and public health authorities that have looked at the question repeatedly. But irrespective of the conclusions that the scientific community has reached, scientists do not have a privileged position within a values debate beyond clarifying when science is being misused. Such values based debates should focus on any real issues of contention and be resolved through the political process – whether local or nationally.
Fluoride Free NZ response: The Ministry of Health and its expert dental, public health and scientific advisors also incorrectly believed that fluoridation worked by fluoride being swallowed when in fact the story changed in 1999 when the CDC admitted that fluoride works by contact with the surface of the tooth.