The Case Against Fluoride coverThe Case Against Fluoride

In February 2011 Mr Justice Holman at the High Court endorsed the South Central strategic health authority's decision to add fluoride to Southampton's water, in spite of the opposition of Hampshire council and many residents. 

The NHS proposed the fluoridation because tooth decay in children from Southampton is more than twice the national average. Opponents of the move are concerned that fluoride can lead to health issues such as thyroid problems and cancer. 

In their book The Case Against Fluoride, Spedding Micklem, Emeritus Professor, Edinburgh University, and his co-authors examine the issue in depth. 

This specially-written article by Spedding Micklem looks at the background to the fluoride debate:

Water fluoridation – sixty years of controversy and still going strong

In the beginning

Fluoridation – the addition of fluoride to community water supplies in order to prevent dental caries - was first trialled in the USA in the 1940s. Surprisingly, its use was endorsed by the US Public Health Service in 1950, before any of the trials had been completed. The background to these events is described in Chris Bryson’s exhaustively researched book The Fluoride Deception. Other endorsements by public health bodies and professional associations in the USA and elsewhere soon followed, rarely supported by any additional research to establish the measure’s effectiveness and safety. Objections came from many directions, including a range of legitimate questions from independently minded scientists, doctors and dentists, and ethical objections to the whole idea of forced medication.

The practice of fluoridation has spread, particularly within the English-speaking world and some South American countries. The few countries in continental Europe that adopted it initially have now abandoned it, as has Scotland. The UK, after carrying out three small trials, introduced the practice in certain areas, including Birmingham and Newcastle, in the 1960s, but the proportion of the population affected is still only about 12% of the total. The Republic of Ireland, in contrast, is almost entirely fluoridated.

And today

Remarkably little has been resolved in the intervening 60 years.  On the back of all those prestigious endorsements, “safe and effective” has become the mantra of the pro-fluoridation camp and a dogma-driven foundation of government policy in some countries. It is considered so nearly axiomatic as to be hardly worth further investigation. That is, of course, a very unscientific approach, since a basic tenet of science is the need to question its existing assumptions.  The policy is being pursued with renewed zeal in the USA, Australia, New Zealand and parts of Canada, often in the face of stiff local opposition. In England, we have the fiercely contested and undemocratic decision to fluoridate parts of the Southampton area.  However, as more research is published, the strength of the opposition case is growing.

As always, the discussion revolves mainly around three questions:  

1. Does fluoridation work? 2. Is it safe? 3. Is it ethically justifiable?

Does it work?

It may seem astonishing that this should still be a matter of contention, but it is. One fundamental thing has changed since the early days. Then, it was believed that fluoride had to be incorporated into the enamel of the developing tooth in early childhood to protect it from decay. Since the 1990s, however, it has been generally agreed that any benefit is due to topical action on the surface of the tooth. This can be achieved with fluoride-containing toothpaste or through applications of fluoride by the dentist, so the value of swallowing fluoride is increasingly questioned.

It is clear that fluoridation today offers less benefit than was claimed on the basis of early trials. The results of large surveys carried out in the USA and Australia and published in the last twenty years do show some reduction in caries in children brought up drinking fluoridated water, but the average saving reported is extremely small – less than one tooth surface out of 128 in a child’s mouth. Proponents generally prefer to talk about percentage reductions, but percent figures, while they may sound impressive, are almost meaningless when one is dealing with such small numbers. Recent evidence is suggesting that even these small effects may actually represent not a true reduction in caries, but a delay in its onset – the delay being attributed to ingested fluoride delaying the emergence of teeth from the gums. Since caries only starts to develop after teeth emerge, any delay in emergence will mean a delay in caries onset, so that at a given point in time there will be fewer cavities. Further investigation of this important point is needed. 

In the UK, proponents of fluoridation have been slow to acknowledge these large surveys, preferring to rely on smaller local investigations, sometimes backed up by scientifically invalid comparisons, particularly between Birmingham (fluoridated, fewer cavities in five year olds) and Manchester (non-fluoridated, more cavities in five year olds). The trouble with this comparison is that the two cities are dissimilar across a range of health and deprivation parameters, of which tooth decay is just one. They cannot all be due to the presence or absence of fluoride in the water. On the contrary, it is widely accepted that dental health is highly correlated with socioeconomic status, diet and general health; so Manchester’s childhood tooth decay may have nothing to do with a lack of fluoride.

Nevertheless, there is some evidence to support proponents’ belief that fluoridation is of particular benefit to the poor and helps to reduce dental health inequalities; but experience worldwide shows that it is unlikely to be effective unless improvements in diet, education and access to dental care are put in place at the same time.

In summary, the answer to the question “does fluoridation work?” is: maybe, a bit, in some circumstances. Given the availability of fluoride-containing toothpaste and other means of applying fluoride topically, that provides little justification for its current energetic official promotion in some countries, including the UK, or for the expense and (see below) risks involved.

Is it safe?  

The first thing to realise is that it is impossible to prove that something is absolutely safe for all people in all circumstances; so we have to consider the ways in which it might not be safe and evaluate the risks involved.

Normally, when a new drug is introduced, procedures are put in place for recording possible side effects. Fluoridating countries have not done this. On the contrary, people who believe themselves to be sensitive to fluoride have often been derided and physicians who report such problems discredited, so very little information has been built up. Some general health surveys have been conducted, comparing fluoridated and non-fluoridated communities, but the design has rarely sufficed to identify problems affecting a small minority of people. One of the original trials provided evidence of abnormalities in cortical bone and of earlier menarche in girls, but these were never followed up.

There has also been a reluctance to pay any attention to animal studies or to human investigations on populations in countries such as China, India, Mexico and Iran that are exposed to excessive fluoride in their groundwater.

Is there any real reason to suppose that fluoride might be harmful?

Yes, in fact several. Here are some:

            1. Fluoride has long been known to affect the activity of a wide variety of enzymes, so it might be expected to have a variety of effects on metabolic processes. There is little information on how important such effects may be in people drinking fluoridated water.

            2. Fluoride exposure in early childhood produces defects in the enamel of the permanent teeth (dental fluorosis). This is the one harm that proponents of fluoridation acknowledge. It is usually more or less inconspicuous, but in a minority of cases it results in unsightly discoloration and pitting of the enamel. Fluorosis has been reported to affect as many as 40% of people in the UK, and up to 70% in fluoridated areas. A high prevalence of fluorosis has been a major factor in a very recent re-evaluation of fluoride’s safety by the US Environmental Protection Agency (EPA) and the resulting recommendation by the US Public Health Service to reduce the ‘optimal’ concentration of fluoride in drinking water from 1 part per million (ppm) to 0.7ppm. In fact, a close reading of EPA’s calculations shows that there is no room for manoeuvre between a concentration able to cause severe fluorosis in some people and the concentration supposedly required to reduce caries. Infants in particular will get far too much fluoride if fed formula made up with fluoridated water.

            3. If a brief exposure to fluoride early in childhood is enough to severely damage the teeth, what may a lifetime’s accumulation do to the skeleton, where about 50% of ingested fluoride localises. We know from studies in India and elsewhere that higher concentrations of fluoride can cause crippling skeletal fluorosis, in which the vertebrae fuse to form a rigid rod. The earlier stages of the disease resemble arthritis. To what extent drinking fluoridated water can induce these earlier stages is unknown. There is also mixed and inadequate information about the contribution of fluoride to bone fractures.

            4. People with kidney disease may excrete fluoride less efficiently than normal, resulting in greater accumulation in the skeleton and probably other sites such as the pineal gland. There is also evidence the fluoride can itself damage the kidneys.

            5. Fluoride has been authoritatively described as an endocrine disruptor able to depress the activity of the thyroid gland. Proponents claim that there is no evidence that ingestion of fluoridated water has such an effect, but what they really mean is that no one has seriously looked.

            6. Numerous animal studies demonstrate that fluoride can damage the brain. More than 20 studies from China, Mexico and elsewhere have linked consumption of fluoride at concentrations  of about 1-10 ppm with reduced IQ in young children. Proponents spend a lot of time looking for reasons to disregard these studies, but no comparable investigations have been carried out in Western countries.

            7. One careful study links consumption of fluoridated water during a critical period of childhood with an increased risk of developing the rare bone cancer osteosarcoma. Again, proponents have shown more interest in trying to discredit this than in following it up.

So where does all that leave us?

Can drinking artificially fluoridated water cause any of these problems, apart from dental fluorosis? - not proven.

On present evidence, how high is the risk that they may do so, at least in a minority of people? - very high.

With how much diligence are the governments of fluoridating countries, including the UK, pursuing answers to these questions? - very little.

What should be done meanwhile? This is the big bone of contention between proponents and opponents. Proponents appear to believe that it is acceptable to continue and even extend fluoridation unless or until there is conclusive proof that serious harm directly results  (severe dental fluorosis does not count); they have not exerted themselves to look for such proof. Opponents consider that the cumulative risk posed by the potential harms outlined above is more than sufficient to invoke the precautionary principle and halt fluoridation until such time as the risk may be shown to be groundless.

I leave the reader to decide which is the more tenable position.

Is it ethical? This is of fundamental, and for many people overriding, concern – specifically, the right of the individual to refuse medication. There is also an ethical dimension to the precautionary principle and the failure to follow it. Proponents have tried to counter with misleading claims that fluoride is a nutrient, not a medicine, and even by arguing that it is unethical not to fluoridate, because the majority should be willing to make sacrifices for the sake of helping underprivileged children.

Paul Connett, James Beck and I hope that, by offering a full account of the scientific background to fluoridation, our book will help readers to make up their own minds on this and the other questions underlying the fluoridation controversy.

Spedding Micklem

Emeritus Professor, University of Edinburgh

May 2011

Case Against Fluoride cover

The Case Against Fluoride by Paul Connett, James Beck and H. S. Micklem is published by Chelsea Green and distributed in the UK by Green Books.

For more information or to buy the book now, visit our online bookshop