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Vol. 16, No. 6,1986

Fluoride: New Grounds for Concern

By Mark Diesendorf and Philip R.N. Sutton

The intake of fluorides, salts of the element fluorine, has increased markedly over the past quarter century. Fluorides are added to a number of consumer products, such as toothpastes, mouth-rinses and gels, in order to try to reduce tooth decay in children. Moreover, fluoridation, the addition of fIuorides to town water supplies, contributes to human fluoride intake a considerable involuntary component, a large part of which is derived from foods processed in, and drinks reconstituted with, fluoridated water.

Even very low levels of fluoride in water and air are damaging to certain species of plants. High doses are well known to be poisonous to animals and humans-indeed, sodium fluoride is used as a rat poison.

How safe are fluoride products and fluoridation for people? Are they really as beneficial for children's teeth as dental and medical associations in extensively fluoridated countries, such as Britain (10 per cent fluoridated), the USA (50 per cent) and Australia (67 per cent) claim? Should people be, in effect, compelled to drink fluoridated water? Who profits from the marketing of products which are supposed to reduce tooth decay, even though children continue to eat junk food? Fluoridation, and the marketing of other fluoride products, raise scientific controversies, unresolved ethical issues and political questions. They are matters worthy of serious scrutiny.

On the world scene, there are considerable divisions of opinion. In continental western Europe, fluoridation was introduced beyond the pilot plant stage only in Sweden, the Netherlands and West Germany. In each of these countries, after trials lasting many years, it has been terminated on health and/or ethical grounds. In contrast, Australia, is one of the most extensively fluoridated countries in the world. In some circles in Australia, those who question fluoridation are branded as "ignorant cranks".

Nevertheless, in this article, we attempt to draw attention to scientific evidence, published in international journals over the past five years, which indicates new grounds for concern about potential health hazards from low doses of fluorides. We also explain why the claims that fluoridation is responsible for the substantial reductions in tooth decay observed in developed countries, are being examined with growing scepticism by scientists.

On the question of risks, some dental and medical authorities have somehow managed to convey the incorrect impression that, apart from strengthening teeth, fluoride is inert in the human body and is therefore harmless. The biochemistry and physiology of fluoride in the human body contradict this notion. Not only is fluoride incorporated into teeth, but also into bone and many soft tissues. On account of its small size, the fluoride ion is very active biochemically, possibly only exceeded in activity by the hydrogen ion. It is therefore not surprising that a wide range of adverse effects on biological systems and on human health have been reported in the scientific literature. We first draw attention to a group of people who may be at particularly high risk.

Bottle-fed Infants

Infants who are fed with milk formulae prepared with fluoridated water take in about 100 times the amount of fluoride which they would receive from breast milk. This is because there is a kind of physiological "barrier" which largely prevents fluoride from entering breast milk, even when the mother is on a relatively high fluoride diet. This barrier could have evolved to protect the developing infant in environments which have naturally higher than average fluoride levels. It is widely accepted by nutritionists that breast milk contains the optimum amounts of all nutrients required for the proper development of the infant, at least for the first few months after birth. One wonders what the massive unnatural overdose of fluoride is doing to bottle-fed infants, particularly since it is now known that breast-fed infants remove fluoride from their bones and excrete more fluoride than they ingest.

Genetic Damage

Genetic effects are inherited effects. They are known to be produced by quite a large number of chemicals in the environment and by ionising radiation. In the 1970s, several scientific papers reported that fluoride causes genetic damage to some plants and animals, and to animal cells grown in tissue culture on suitable nutrients in the laboratory. At that time there were some contradictory reports and the situation was unclear.

However, since 1980 several scientific papers have been published in major international journals showing clearly that, under certain conditions, fluoride damages the DNA molecule, hence the primary genetic material which contains the genes.

In particular, a group at the Nippon Dental University in Tokyo has shown that fluoride disrupts the DNA in cells taken from the human mouth and from the human foreskin, and grown in tissue culture. Although the fluoride concentrations used in these experiments were much greater than that recommended by the pro-fluoridation dental associations for fluoridated water (about 1 mg fluoride per litre of water), the concentrations were comparable with those existing in people's mouths, following teeth cleaning with fluoridated toothpaste, mouth rinsing with a fluoridated rinse, or application of a fluoridated gel to the teeth.

The observation of genetic damage raises the question as to whether consumers should continue to use these fluoridated products. It also suggests the possibility that using fluoridated water may produce genetic effects; to elucidate this, more experiments are needed at lower fluoride concentrations. It should be noted that some genetic effects, such as changes in mitosis and DNA synthesis in cell cultures, have been reported at fluoride concentrations as low as 1.5mg/litre.

Cancer?

Chemicals which are mutagenic are also often, though not always, capable of inducing cancer in humans. Some of the experiments mentioned in the previous section provide strong evidence that fluoride is a mutagen. But is it also a human carcinogen?

So far, epidemiological studies do not seem to have established a higher cancer mortality rate in general in fluoridated cities compared with unfluoridated cities. However, it should be borne in mind that epidemiological studies generally contain a number of untested assumptions, such as the selection of data and procedures for analysing that data, and so a clear-cut answer cannot be given at this stage. If there is a cancer risk, it is possible that it mainly occurs at the higher levels of fluoride exposure corresponding to the use of toothpastes, gels and mouth-washes.

Nevertheless there are genuine grounds for concern. Experiments carried out in 1984 indicate that at least one type of mammalian cell, grown in fluoride-treated culture, induces tumours when injected back into the living mammal. Untreated cells do not have this effect. While there is still a big gap between the result of this kind of experiment and the direct induction or the acceleration of the development of cancer by fluoride in humans, the evidence remains worrying.

Enzyme Inhibition

Enzymes are proteins which act like catalysts to facilitate and control chemical reactions in living creatures. For many years, it has been known that fluoride interferes with the action of a number of enzymes in the human body. The health implications of these changes are still unknown, but the possible damage is profound and diverse.

One of the main research advances in this area in the 1980s has been to shed light on the mechanism by which fluoride inhibits enzymes. Fluoride can interfere with an important chemical bond, known as the hydrogen bond. This results in changes in the shape of enzyme molecules, effecting their ability to fulfill their functions. With regard to DNA, which is like a spiral staircase consisting of two bannisters held together with hydrogen bonded steps, fluoride, by affecting those hydrogen bonds, can completely disrupt the molecule, readily accounting for the genetic damage mentioned earlier.

Well-known Health Hazards

Prior to 1980, evidence for the existence of a number of other ill effects from ingesting fluoridated water, fluoride toothpaste and tablets was reported in the scientific literature but ignored or denigrated by the promoters of fluoridation. We mention here only those hazards which are well documented. However, these could be just the tip of the iceberg. The problem is that Australian, British and USA doctors are incorrectly led to believe by their professional associations that there are no adverse effects from fluoridation and the use of fluoride containing products, apart from the mottling of teeth. Even this effect is stated to be so slight that it can be detected only by experts.

Dental fluorosis

Dental fluorosis (mottling of teeth) is not just a "cosmetic" problem. Amongst fluoride researchers, it has been recognised for many years as the first visible sign of chronic fluoride poisoning. It used to be considered that mottled teeth would occur in about 10 per cent of children who drank water with fluoride concentrations at or near the level recommended by fluoridation promoters. Recently, evidence has been published that this percentage gas risen substantially in some fluoridated areas, such as Auckland, New Zealand, where about one quarter of the children are affected. A contributing reason for this increase must be the substantial increase in the fluoride dose which is now ingested from numerous sources by many populations (see below).

Skeletal fluorosis

A bone disease called skeletal fluorosis is prevalent in several parts of the world (e.g. India, Qatar and Japan) where drinking water naturally contains fluoride in concentrations equal to or slightly above that recommended for fluoridation. Skeletal fluorosis involves changes in the bone structure which are generally detectable on x-rays. Extreme cases (such as those often seen in India) have readily visible symptoms and include crippling of those affected. These extreme forms have not been reported in Australia, probably because other factors are important, such as nutrition which may be inadequate in those with symptoms. It is now increasingly recognised that the nutrition of many Britons, Americans and Australians falls far short of being adequate. To date no scientific study has been carried out in those countries to identify the extent of skeletal fluorosis.

Haemodialysis

In the 1970s, several major overseas hospitals, such as the Mayo Clinic, Ottawa General Hospital and Montreal General Hospital, reported cases of serious bone diseases in patients undergoing long-term treatment on kidney machines which used fluoridated water. Nowadays, many (but not all) kidney machines have a "filter" to remove fluoride from the water.

Intolerance to Fluoride

In a small fraction of people, fluoridated water, fluoride toothpaste and fluoride tablets produce a variety of intolerance effects, including skin eruptions, headaches, 10 gastric upsets, headaches increased desire to urinate and, in the case of toothpaste, mouth ulcers. All of these effects have been re ported by clinicians in the medical literature. Some have been confirmed by a "blind" and a "double blind" controlled trial.

Fluoride Dose

The fluoridation of water supplies is called "controlled fluoridation" by proponents because the aim often not achieved-is to add fluoride to town water supplies at a fixed concentration: namely, about 1 mg of fluoride per litre of water in temperate climates. However, the term "controlled" is misleading because the individual dose of fluoride depends not only on the concentration in the water but also on how much water (and tea, beer, soft drink, reconstituted fruit juice, etc), people drink, and on how much food processed with fluoridated water they eat.

As recently as 1971, leading proponents of fluoridation from the dental profession and even the US National Academy of Sciences stated that the total average daily intake of fluoride from fluoridated water, from both direct and indirect pathways, was only about 1 mg for an adult. These authorities seemed unaware that measurements had already been made on sedentary people yielding daily intakes of 2 to 5.5 mg. In manual labourers, these intakes may be doubled. To these figures must be added the intake from atmospheric pollution and from natural sources (e.g. strong tea made with water originally having a negligible fluoride content contains about 2 mg per litre) and consumer products (e.g. dentrifices and some medical drugs).

Recent studies have shown that young children (ages 2-6) swallow about one-third of the toothpaste applied to the brush, producing a substantial peak in the fluoride concentration in the blood plasma. Since the concentration of fluoride in toothpaste is about 0.1 per cent, daily doses of fluoride of 0.5mg from toothpaste are likely.

We believe that the current practice of marketing fruit flavoured fluoride toothpaste is dangerous. A single 75gm tube contains about 75mg of fluoride. There is no doubt that this is a toxic dose, which could even be fatal for some children. How is it that our medical and dental authorities have allowed fruit-flavoured fluoride toothpaste onto the market without making a public protest? The answer, we suggest, lies in the close relationship between some of these authorities and commercial interests, and in the perceived requirement not to shake public confidence in the safety of fluoride, even to the extent of suppressing information about its well-recognised dangers.

In heavily fluoridated countries such as Australia, it is not uncommon for children to receive fluoride not only directly and indirectly from the water supply and from natural sources, but also from atmospheric fluoride pollution, fluoride tablets, toothpaste, mouthrinses and gels (about 1 per cent fluoride). In our experience, when medical and dental authorities campaign for the fluoridation of a town water supply in Australia, they make no serious attempt to assess the total fluoride intake which citizens may already be receiving.

For instance, although the Australian city of Geelong had two major sources of industrial fluoride pollution of the atmosphere, the Health Department of Victoria in a recent letter to the Geelong Water Trust admitted that it had not determined the fluoride levels in the population of any Victorian town before advocating fluoridation. The Department had, therefore, disregarded the resolution of the World Health Organisation which specified that fluoride intake from other sources must be taken into account when considering the introduction of fluoridation.

Readers may be surprised to learn that there is no official "safe" daily dose of fluoride expressed in mg per kg of body weight per day. Dentists and state authorities seem to think only in terms of fluoride concentrations (in mg per litre) in the water supply which, as the volume drunk is not considered, bear little relation to doses ingested by individuals. For the one ill effect of fluoridation which is generally conceded even by proponents, dental fluorosis, we cannot find even one study of its dependence on dose. This is just one indication of the inadequacy of the research done to back up claims for the safety of fluoridation and fluoride products.

The incomplete data available suggest that the total daily fluoride dose in fluoridated areas is likely to average at least several mg and, for physically active people, could be over 10mg. For comparison, the controlled trials in which intolerance reactions to fluoride were observed, delivered just 1mg of fluoride per day. Even the profluoridation British Royal College of Physicians admits that some patients, when given as little as 9mg per day fluoride in tablets, with the aim of treating osteoporosis, experience nausea, gastric upset and sometimes vomiting. Clearly, if there is a margin for safety for the "average" person, it must be very small. Because of human variability and because of the lack of a controlled dose, it is inevitable that for some individuals there can be no margin of safety.

Nearly 30 years ago, B.C. Nesin, the Director of Laboratories of the New York Water Supply, said that the minimum safety factor is 10mg for substances which are admitted to a water supply, and that such a factor cannot be established with fluoridation at 1mg per litre. He added: "It must be concluded that the fluoridation of public water supplies is a hazardous procedure, people are bound to get hurt, it remains to find out how many and when."

Enormous Benefits?

Claims that fluoridation "reduces dental caries (tooth decay) by about 60 per cent" are based on studies, "trials", or "demonstrations" on various populations.

The earliest studies were those performed by H.T. Dean and colleagues in naturally fluoridated regions of the USA. It is claimed that these studies demonstrate a reduction in tooth decay proportional to the concentration of fluoride in the water supply. Unfortunately, from a scientific perspective, the fact that these studies were qualitative rather than quantitative in nature, the non-random method of selecting data and the high sensitivity of the results to the way in which the study populations were grouped, all show that no firm conclusions can be drawn from these early studies. Indeed, Ziegelbecker, a mathematician, analysed a much larger data set which included that considered by Dean and could not find any relationship between fluoride concentration in drinking water and tooth decay.

The next set of studies, which were used to justify the extensive fluoridation programme in the USA (and subsequently in Australia), took place in several artificially fluoridated towns in North America. These "demonstrations" have been criticised rigorously in a book by Sutton, on the grounds of inadequate experimental design and inadequate statistical analysis. Sutton's critique is generally not cited in the pro-fluoridation literature, despite the fact that it has never been refuted.

Notwithstanding the poor scientific status of the above-mentioned studies in both naturally and artificially fluoridated regions, these studies are still cited as the basis for fluoridation in many pro-fluoridation reviews and reports, including the 1976 report of the British Royal College of Physicians.

"Demonstrations" of the alleged benefits of fluoridation have been performed in several other countries. A few of these, such as some of the early studies in Britain, were better designed experimentally, to the extent that they had unfluoridated control populations and the dental examiners did not know which children came from the control population and which came from the fluoridated test region. (This elementary precaution against bias was not taken in the North American trials.) The selected data from these studies published by the UK Department of Health in 1969 suggested a modest contribution from fluoridation: a reduction in tooth decay of about one cavity per child in fluoridated regions compared with unfluoridated controls of the same age. However, the rate of increase in tooth decay with age was the same in both fluoridated and control cities. A possible interpretation of the data is that there is a delay of 1-2 years in the onset of tooth decay in the fluoridated cities.

The vast majority of the fluoridation "demonstrations" have been no better in scientific standard than the North American ones. Some have even been worse. For instance, none of the Australian studies on permanent teeth had a genuine control population. Moreover, it appears that only one study had adequate baseline data that is, a series of examinations of tooth decay over several years before a population is fluoridated.

It is important to have a control population and to have sufficient baseline data to obtain the time trend in tooth decay before fluoridation so as to find out whether the observed reduction in tooth decay over a period of years is caused by fluoridation or by other environment and lifestyle factors.

There is now growing evidence that tooth decay has greatly decreased in a number of developed countries in both fluoridated and unfluoridated regions. For example, in Sydney, Australia, the Health Commission of New South Wales has reported that the proportion of children with "decay-free" teeth increased from 8 per cent in 1961 to 58 per cent in 1967. However, Sydney was only fluoridated in 1968, and the Health Commission has not published any evidence to support the notion that fluoride tablets and fluoride toothpaste were widely used in Sydney in the above period.

Furthermore, the maximum possible benefit (if any) from fluoridation would surely be achieved for children who have consumed fluoridated water from birth. Yet there is a growing body of evidence which suggests that such "optimally exposed" children have much less tooth decay today than "optimally exposed" children of the same age several years ago.

So it is likely that fluoridation plays a minor role in reducing tooth decay. By pushing strongly to achieve total fluoridation in Britain, the USA and Australia, the promoters are in effect destroying scientific evidence which is unfavourable to their policies.

Misleading Statements

It is not often that State and Commonwealth Departments of Health, and a leading consumers' organisation, publish information which is misleading and, "in some cases, demonstrably false. Unfortunately, this has been the situation with regard to the issue of fluoridation.

Two examples of such publications are:-

1. The anonymous article originally published in the USA magazine, Consumer Reports, and reprinted verbatim in the August 1979 issue of the Australian consumers' magazine, Choice;

2. The introduction to the 1978-79 Annual Report of the Australian Director-General of Health.

A complete analysis of the misleading information in these two articles would require a whole paper in itself. Yet it is important to try and set the record straight. Therefore, we shall mention only some of the basic misleading terminology in these and other profluoridation articles, and give just one example of a false statement.

The Choice article implies wrongly that fluoride has been shown to be an "essential nutrient". However, fluoride, at the levels recommended by pro-fluoridation dental associations, is neither "necessary" nor "sufficient" for sound teeth. In other words, people can have sound teeth without fluoridated water, toothpaste, or tablets and people can have very decayed teeth even though they use all the fluoride paraphernalia. The quality of your teeth depends on a broader range of factors than the presence of virtual absence of fluoride. But, are traces of fluoride, much smaller than those considered above, necessary for life? This has never been established scientifically. Indeed, in 1979, the USA Food and Drug Administration ceased listing fluorine as "essential or probably essential" in human nutrition. In any case, the question of the essentiality of fluorine is irrelevant to the issue of fluoridation and the use of fluoridated products, because minute traces of fluoride are always present naturally in the diet.

The Australian Director-General of Health referred to a "deficiency of fluoride", but there cannot be any such condition. How can there be a deficiency of something which is not even necessary?

The use of the above misleading terminology - "controlled fluoridation", "essential nutrient" and "deficiency of fluoride"-by the promoters of fluoridation and fluoride products is not the language of science but rather that of advertising and public relations masquerading as science.

An example of a statement in the Choice article which is factually false, rather than just misleading, occurs in the section headed "Claim: fluoride is a poison". In speaking of chronic fluoride toxicity in India (where skeletal fluorosis is a major manifestation of such toxicity), a paragraph in this section creates the false impression that such ill effects "are associated with water supplies that contain at least 10ppm of natural fluoride". In fact, in India a number of cases of skeletal fluorosis 242 have been found in several regions where water supplies contain concentrations around 1ppm (1mg per litre). Indeed, it is for this reason that the Indian scientist, S.G. Srikantia, has recommended that the upper limit for fluoride in drinking water be set around 0.5ppm.

The existence of many uncorrected false and misleading statements in apparently authoritative articles promoting fluoridation can be understood in the light of our experience that until the 1980s it was almost impossible to publish or broadcast articles, letters and radio talks which raised awkward questions about fluoridation. Such was the power and influence of the profluoride lobby. In fact very few fluoridation proponents have actually studied the original scientific literature. Organisations which have endorsed fluoridation have done so on faith, relying on the opinions of a small core of active promoters, not on the basis of a detailed study of the issue.

Bibliographny

General scientific reviews of the main known health hazards of fluoridation, as understood in the late 1970s, have been given by G.L. Waldbott, AW. Burgstahler and H.L. McKinney (1978): Fluoridation: the great dilemma. Lawrence, Kansas USA: Coronado Press, 423pp; Philip R.N. Sutton (1980): Fluoridation 1979: Scientific criticisms and fluoride dangers. 285pp, (now out of print but available in libraries); and Mark Diesendorf (1980): "Is there a scientific basis for fluoridation?" Community Health Studies vol. 4, no. 3, 224-230.

D. Rose and J.R. Marier (1977): Environmental fluoride, 1977. National Research Council of Canada, Report No. NRCC 16081.

Glen S.R. Walker (1982); Fluoridation-poison on tap. Glen Walker (GPO Box 935G, Melbourne Vic. 3001) 458pp.

Papers relevant to the overdosing of bottlefed infants with fluoride are:

R.D. Gabovich and G.D. Ovrutskiy (1977): "Fluorine in stornatology and hygiene". Translated from the 1969 Russian edition by the National Institute of Dental Research, DHEW Publication No. (NIH) 78-785, USA Dept of Health, Education & Welfare, Bethesda, pp.171-172;

J. Ekstrand et al. (1981): Br Med J vol. 283, 761-762;

S. Esala et al. (1982): Br J Nutr vol. 48, 201-204.

On genetic damage in cell cultures, see

T. Tsutsui et al. (1984): Mutation Research vol. 139, 193-198 and vol. 140, 43-48.

On tumours induced in animals by fluoridated tissue cultures, see

T. Tsutsui et al. (1984): Cancer Research vol. 44, 938-941.

On the disruption of the hydrogen bond of fluoride, see

John Emsley et al. (1982): J. Chem. Soc., Chem. Commun. No. 9, 476-478;

S.L. Edwards et al. (1984): J. Biol, Chem. vol. 259, 12984-12988.

For an example of enzyme inhibition by low doses of fluoride in vivo, see

D.B. Ferguson (1971): Nature New Biology vol. 231, 159-160.

Studies on fluoridated toothpaste and gels swallowed by children are reported in

Jan Ekstrand et al. (1980): Caries Res. vol. 14, 96-102; (1980): J. Dental Res. vol. 59, 1067.

Reports of skeletal fluorosis from water supplies in India with fluoride concentrations around lmg/litre, have been published by

A. Singh, S.S. Jolly and B.C. Bansal (1961): Lancet i, 197-200; S.S. Jolly et al. (1973): Fluoride vol. 6, 4-18;

S.G. Srikantia (1984): Bull. Nutrition Foundation India, April.

For reports on skeletal fluorosis in Qatar and Japan, respectively, at fluoride concentrations around 1mg/litre, see:

H.A. Azar et al. (1961): Ann Int Med vol. 55, 193-200 and

Y ' Hirata (1950): Tokyo Ito Shinshi vol. 67, 9-14, quoted by G. Minoguchi (1970) in World Health Organisation: "Fluo~rides and human health", Geneva.

Critiques of "demonstrations" of the alleged benefits of fluoridation are:

Philip R.N. Sutton (1960): "Fluoridation: errors and omissions in experimental trials." 2nd ed. Melbourne University Press;

R. Ziegelbecker (1981): Fluoride vol. 14, 123-128.

The reduction in tooth decay in unfluoridated regions has been reviewed by

D.H. Leverett (1982): Science vol. 217, 26-30. The reduction in tooth decay in pre-fluoridation Sydney was revealed in

J.S. Lawson et al. (1978): Med J. Aust. vol. 1, 124-125.

For an account of the struggles of an eminent USA allergist against the suppression by medical, dental and public health authorities of his clinical observations of intolerance reactions to fluoride, see

G.L. Waldbott (1965): A struggle with titans. New York, Carlton Press.

For an excellent analysis of the politics of fluoridation in Australia (i.e. who controls, who funds and who profits), see the forthcoming book by Wendy Varney: Fluoridation-a case to answer. Hale and Iremonger (in press). See also Waldbott et al (1978), op. cit. chap. 17.

Mark Diesendorf BSc PhD, a principal research scientist in the CSIRO Division of Mathematics and Statistics, Canberra, is currently setting up a private consultancy, Science in the Public Interest, Australia. He is president of the Australasian Wind Energy Association.

Philip R.N. Sutton DDSc FRACDS was appointed senior lecturer in Dental Science in 1963 at the University of Melbourne's School of Dental Science, but resigned in 1974 to have more time to extend his studies on dental conditions in Polynesia and Micronesia. In 1959, Melbourne University Press published the first edition of his monograph, "Fluoridation: Errors and Omissions in Experimental Trials", which he updated in 1980