Fluoride

by Mark Watts [*Scanned from the booklet 'Fluoride' - a printed supplement to the TV documentary screened on Channel 4  on 19th June, 1997]

Published in 1997 by Channel 4 Television, 124 Horseferry Road, London SW1P 2TX.

Produced by Broadcasting Support Services to accompany Health Alert: Don't Swallow Your Toothpaste, made by Daylight Productions for Channel 4 and first shown in June 1997).

ISBN: 1 85144 196 4

Author: Mark Watts
Editor: Paula Snyder
Editorial consultants: Peter Millson, Denise Searle
Designer: Broadcasting Support Services
Map: Nick Pearson
Printer: ISP, Luton

Distributed by Broadcasting Support Services, Broadcasting Support Services provides follow-up services for viewers and listeners and runs long-term helplines. For further copies, please send two first-class stamps to:

Health Alert: Fluoride
PO Box 4000
London W12 8UF

Contents

Introduction

What is fluoride and how is it used?

The background

Early observations

Fluoride and the atomic bomb

Fluoridation: an unknown quantity

Fluoridation in the UK

Fluoridation in the rest of the world

Fluoridation and the law

The debate

Benefits

Risks

What you can do

Fluoride in the diet

Fluoride in dental products

Further information

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Introduction

Fluoride is generally portrayed as an entirely beneficial substance that reduces tooth decay and produces gleaming white teeth. But the real picture is more complicated. It is well established, for instance, that too much fluoride can discolour children's teeth, and some research suggests that quite low levels of fluoride may be harmful in other, more serious ways.

As a result, some people strongly oppose fluoridation - the addition of fluoride to water supplies. But the dentists' professional body, the British Dental Association, is very much in favour of fluoridation. One in ten Britons currently live in fluoridated areas, and the Association aims to increase this to one in four by the year 2000.

Should you be concerned about fluoride and fluoridation? This booklet looks at the evidence and suggests what you can do to minimise any risks.

What is fluoride and how is it used?

Fluoride comes from the reaction of fluorine with another element. It is naturally present in the earth's crust, and often in water at very low levels and occasionally at high levels.

Sodium fluoride, formed from fluorine and sodium, is used in toothpaste and has been used in fluoridation. It is also used, in much higher concentrations, as a rat poison and insecticide.

Other fluorides include sodium monofluorophosphate (also used in toothpaste) and hexafluorosilicic acid (a phosphate fertiliser industry by-product used in water fluoridation). A company that supplies hexafluorosilicic acid to British water companies warns that this compound is 'toxic and corrosive to all tissues' and requires careful handling.

All this sounds alarming, and some researchers believe there is good cause for concern. But some toxic (poisonous) substances can be used in a way that benefits health. Many substances used in medicines are toxic, for . example, and chlorine, which was used as a poisonous gas in the First World War, is one of the chemicals used to purify drinking water. However, anti-fluoride campaigners say that fluoride is different, because the gap between levels that are thought to be safe and levels that are toxic is unusually small.

The background

Early observations

Fluoride has long been linked both to reduced tooth decay and to the discolouration of teeth. An American dentist, Dr Frederick McKay, noticed in 1901 that many of his patients in Colorado Springs had brown mottled tooth enamel. He blamed the local water, but it wasn't until 1931 that the cause was identified as naturally high fluoride levels in the water.

In Britain, a study by Norman Ainsworth in 1925 reported that tooth decay among children living in Maldon, Essex, was well below average, but many children also had mottled enamel. In 1933, he found that Maldon's water at that time had naturally high fluoride levels.

Fluoride and the atomic bomb

Health Alert uncovered the secret and extraordinary role that the Manhattan Project, which built America's first atomic bomb, played in the early promotion of fluoridation.

The first lawsuit over the atomic bomb centred on fluoride pollution, not radiation. A group of farmers sued the authorities for $400,000, claiming that pollution from fluoride, a by-product of a New Jersey atomic bomb factory, had destroyed their crops in 1944. But they had to withdraw the action when their money ran out.

Declassified documents show the lawsuit was discussed by America's then secretary of war, who headed the Manhattan Project. The project's chief pharmacologist, Dr Harold Hodge of the University of Rochester, New York, then wrote a secret report which recommended tackling local residents' concerns by promoting fluoride as good for teeth.

His suggestion was adopted. In 1946, scientists funded by the Manhattan Project presented a study showing that fluoride exposure improved dental health among factory workers. But a secret draft version of their report, now declassified, reveals that the published version made key omissions. The published paper reported, for example, that the workers had 'little or no active caries' (tooth decay), but the suppressed version said they had hardly any teeth at all.

Moreover, in 1944 Dr Hodge wrote in a memo that he had 'clinical evidence' that fluoride affected the central nervous system. No mention of this appears in the published literature, however, and animal studies to investigate further were stopped. But now new research supports Hodge's view (see page 16).

Fluoridation: an unknown quantity

One of the first pilot schemes to add fluoride to a water supply was introduced in 1945 in Newburgh, New York. Dr Hodge was the study's leading adviser and, without the residents' knowledge, he conducted tests to see what the effects on humans were. One of the tests showed that the fluoride concentration in placenta tissue in 12 Newburgh patients was three times higher than in people from non-fluoridated areas.

In the same year, another leading fluoride proponent, Dr Peter Dale, told the head of the Manhattan Project's medical section in 1945: 'It is unknown what the critical levels of... F [fluoride] storage in man are, or whether they may have a potentially deleterious effect.'

Despite the fact that it remained an unknown quantity, fluoridation was later accelerated in the USA.

Fluoridation in the UK

A delegation from the UK's Ministry of Health examined fluoridation in America in 1952. On its recommendations, fluoridation was introduced between 1955 and 56 in Watford, Kilmarnock and part of Anglesey.

The government reported in 1962 that tooth decay, which was then rampant, was 50% below average in five-year-old children in the fluoridated areas.

Birmingham city council decided to fluoridate in 1964, and Newcastle followed in 1968. After the British pilot schemes had run for 11 years, fluoridation was deemed safe.

Today around 5.5 million Britons - about one in ten - live in fluoridated areas (see table; page 9). In the West Midlands health region, about 3.4 million people (65% of the region's population) have fluoridated water. Birmingham is the largest fluoridation centre in Europe. More than one million people in the Northern region (34% of the population) also have fluoridated water. In addition, there are a small number of fluoridation schemes in the Mersey, North West Thames, Oxford, Trent and Yorkshire regions, as well as in Northern Ireland.

Water fluoride levels can vary from street to street. To find out whether you live in a fluoridated area, ask your water company (look on your water bill or in the telephone directory for the company's number).

Regional Health Authorities in the UK.

Fluoridation in the rest of the world

More than 210 million people worldwide have artificial fluoridation.

Only 2% of Europe is fluoridated. The Republic of Ireland, which made fluoridation compulsory in 1964, and the UK account for most of this. The only other EU country with any fluoridation is Spain.

Hungary, Switzerland, France and Germany have made fluoridated household salt available as an alternative to water fluoridation.

Some countries, including Holland and Sweden, introduced fluoridation and then banned it after public pressure. Ironically, the hexafluorosilicic acid used to fluoridate water in the UK comes from Holland.

America is the world's most fluoridated nation. Half its population - around 135 million people - have artificially fluoridated water. Other countries with fluoridation schemes include Argentina, Australia,
Canada, Hong Kong, Mexico, New Zealand and Singapore.

Fluoridation and the law

A Scottish court ruling that fluoridation had no basis in law prompted the UK government to introduce the Water (Fluoridation) Act in 1985. Under this Act, local health authorities can decide, after consultation, whether fluoridation should be introduced. They can then ask the water supplier to fluoridate at the health authority's cost.

More than 50 health authorities want to extend fluoridation, especially in areas with poor dental health. These authorities are in the Mersey, Northern, the North West, Oxford, Trent, Wessex, West Midlands and Yorkshire regions, as well as Northern Ireland and Scotland.

However, water companies keep refusing requests to fluoridate, citing legal worries. In Northern Ireland, the government, which is responsible for water supplies in the province, decided in early 1997 against fluoridation because of opposition.

Since the 1985 Act, no new fluoridation schemes have been introduced. As a result, a campaign has been launched to change the law, led by the British Dental Association, the British Medical Association, the National Association of Health Authorities and the British Fluoridation Society. One option is to make fluoridation compulsory following a health authority request.

The Debate

Benefits

Fluoride is believed to slow down tooth decay by strengthening tooth enamel. It is thought to be most effective if applied directly to the teeth, so we are advised to use fluoride toothpaste regularly. The British Dental Association says that clinical trials have shown that fluoride toothpastes have been the main cause of the decline in tooth decay in Europe over the last two decades (though, as with most statistics, different interpretations are possible - see page 12).

Many surveys - the British Dental Association cites 130 studies in more than 20 countries, including the UK - suggest that fluoride in the water supply also reduces tooth decay, by 40-60%. And other studies have shown no adverse effects on health at the `optimal' level of one part per million. The Department of Health accepts these findings, saying that fluoridation is effective and safe at the optimal level.

However, the anti-fluoridation lobby group, the National Pure Water Association, not only believes that fluoridation puts health at risk, it also doubts that fluoridation really reduces tooth decay. The group points out that countries that have not introduced fluoridation have also seen dramatic improvements in dental health, and that the Republic of Ireland, which is the only completely fluoridated country in Europe, comes only sixth in official European dental health league tables.

One of the reasons why fluoridation is such a controversial issue is that many other factors, such as prosperity, diet and education, affect dental health. This means that it is difficult to draw firm conclusions from statistics comparing different communities and countries. The same difficulty applies to studies comparing the amount of tooth decay before and after fluoridation in a specific area.

Risks

How much is too much?

Fluoride is poisonous. It is widely accepted that 2.5 to 5 grams can kill an adult by causing breathing failure or heart failure.

However, this sort of dose is thousands of times greater than a person's average daily intake of fluoride in Britain, and trace amounts of fluoride do not cause obvious damage to health. The question is whether artificially increasing the amount of fluoride we consume, for instance by fluoridatinq water supplies, poses long-term health risks.

On one side of the argument, Michael Lennon, Professor of Preventive Dentistry at Liverpool University and chairman of the British Fluoridation Society, said on Health Alert that the 'experience over 50 or 60 years, with now hundreds of millions of people ... none of that experience and none of that research suggests to me that there's any major problem'.

However, Paul Connett, a chemistry professor at St Lawrence University, New York, and a leading anti-pollution campaigner, compares our understanding of the effects of fluoride to our understanding of the effects of lead in the early 1970s. He suggests that fluoride, like lead, may even affect mental development (see also page 16).

'It was finally proven that low levels of lead, lower than caused visible symptoms, were in fact damaging a child's mental development. I think we are going to find the same things with fluoride.'

The particular concern about fluoride is that levels that can damage health are not much higher than levels that are thought to be safe. Professor Connett told Health Alert that scientists normally want the toxic dose to be a hundred times greater that the therapeutic dose. But the average dietary intake of fluoride in Britain is estimated at 1.82 milligrams per day, and it is widely accepted that 4 milligrams per day over a period of 20 years or so can damage bones (see page 14 for more about fluoride and bone damage). Even Dr John Hein, a fluoridation supporter and Colgate's first dental director, conceded) on the programme that:

'It is a very close relationship between the benefits from fluoride, at levels of 1 part per million of the drinking water, to the beginning of the toxic effects ... if we were starting all over again, and had no research data at all, we probably could not come round to getting fluoridation accepted today, because people would say, "Oh, it is just too close. We can't possibly do that."'

Another consideration is that only a tiny proportion of artificially fluoridated water is drunk. Much of it goes into the environment, and may enter the food chain. No research has been done in this area, however, so any increase in fluoride intake from this source is not known.

Dental fluorosis

Dental fluorosis, which is caused by fluoride, affects the second teeth. The signs range from fine white lines on the enamel to unsightly brown staining or mottling. The enamel may even crumble.

The worst form of fluorosis is rare. It is not known how many children are affected overall. The National Register of Children with Dental Fluorosis says it has more than 400 youngsters, affected to varying degrees, on its books.

The severity of fluorosis depends on how much fluoride is consumed while the second teeth are forming (before they emerge) and on other factors such as body weight. The key period is from birth to eight years old, and the greatest risk is during the first two years (see 'Fluoride in dental products' on page 18 for advice on minimising the risk of fluorosis).

Fluorosis is treated by burning off the enamel with acid and covering the teeth with veneers. This cannot be done until a child's head has stopped growing, at about the age of 16 (though a younger child can sometimes have temporary treatment). The procedure costs more than £100 per tooth and has to be repeated several times in a lifetime.

Fluorosis is the first sign of excessive fluoride intake, and some scientists believe it may be a warning of other health problems to come. 'It is clear that when you've got to the point of damaging your teeth,' says Professor Connett, 'you've got to be worried about what it is doing to your bones, or what it will do to your bones in the future.'

Bone damage

Half the fluoride taken in by the body is excreted, but the other half builds up in the bones. Five international studies have found that fluoridated communities have more bone fractures than non-fluoridated areas. A 1992 study in Utah, for instance, found 'a small but significant increase in the risk of hip fracture in both men and women exposed to artificial fluoridation at one part per million, suggesting that low levels of fluoride may increase the risk of hip fracture in the elderly'. ('Hip fractures and fluoridation in Utah's elderly population' by Dr Christa Danielson and others, Journal of the American Medical Association (1992), vol 268, no 6.)

The British Medical Research Council set up a working party in 1993 to investigate. But it said the studies gave 'at most only limited support' for a link between fluoridation and hip fracture and that it 'remained unconvinced that the risk of hip fracture outweighed the benefits of dental protection'.

The Medical Research Council made four recommendations for further studies. Three years later, funding began for one and another has been carried out by overseas researchers (this study did not directly investigate the link between fluoride and bone problems). No action has yet been taken on the other two recommendations.

Immune system impairment

In 1992 a Glasgow research physician, Dr Sheila Gibson, published a study suggesting that fluoride impairs the immune system, affecting the white blood cells. The paper ('Effects of fluoride on immune system function', Complementary Medical Research (1992), vol 6, no 3) notes the rise in conditions such as allergy, auto-immune diseases and post-viral fatigue syndrome over the past 30 years, and points out that the common element in all these is an alteration in the immune system.

However, Stephen Challacombe, Professor of Oral Medicine and Pathology at Guy's Hospital in London, says that most studies have found that fluoride affects the immune system at concentrations 1000 times greater than are found in fluoridated water. His paper, 'Does fluoridation harm immune function?', Community Dental Health (1996), no 13, supplement 2) concludes: 'there is no evidence of any deleterious effect of fluoride on specific immunity and no confirmed report of allergic reactions'.

But the effects on the immune system of low levels of fluoride over long periods are not known. Clearly more research is needed in this area as well.

Effects on the brain and central nervous system

In 1994 Dr Phyllis Mullenix, then head of the Forsyth Research Institute toxicology department in Boston, published a paper suggesting that fluoride disrupted the behaviour of rats by affecting their brains and central nervous systems. Dr Mullenix also believes fluoride harms human mental development. She told Health Alert.

'At a meeting when I first presented the results of these studies, one of the individuals sitting and listening to the results said, "Do you have any idea what you're saying? You're telling us that we're reducing the IQ of children." And basically I said "Yes."'

What's more, according to Dr Mullenix, the level of fluoride needed to affect the brain and central nervous system is lower than that at which bones are damaged.

But Professor Lennon argued that the results from Dr Mullenix's work on animals could not be applied to humans, and that some experts were not even convinced about the effects on rats.

However, as we have seen, as far back as 1944 Dr Harold Hodge said he had 'clinical evidence' that fluoride affects the central nervous system, and there has been a series of research papers since with further clinical evidence. Moreover, last year research from China supported Dr Mullenix's conclusions. One paper, 'Effect of a high-fluoride water supply on children's intelligence' (Fluoride (1996), vol 29, no 4), reported that the IOs of children living in a naturally fluoridated village were 'significantly lower' than IQs of children in a non-fluoridated area.

Once again, more research is needed to confirm the conclusions of these studies and to establish at what levels fluoride might affect the brain and central nervous system.

What you can do

Although fluoride slows down tooth decay, it does not tackle its cause. Tooth decay is caused by acids produced when bacteria break down sugar. So apart from cleaning your teeth twice a day, especially before going to bed at night, the best way of actually preventing tooth decay is to cut the amount of sugar in your diet. This applies both to sugar that you add to food and drinks and to sugar that is already in some foods, especially cakes, biscuits and sweet drinks.

Fluoride in the diet

The average fluoride intake from the diet in Britain is estimated to be 1.82 milligrams daily. Surprisingly, most of this comes from tea, which grows best in soil rich in fluoride.

Research has shown that a cup of tea can contain anywhere between 1.4 and 4.3 parts per million, depending on the strength of the brew and the type of tea (no data has been published on which teas are high in fluoride). Heavy tea drinkers may be taking in as much as 9 milligrams of fluoride daily. So if you want to reduce the amount of fluoride in your diet, drinking less tea is a good way of doing it.

Seafood also naturally contains fluoride. Fish that are served whole, such as sardines and pilchards, have higher levels because the fluoride is concentrated in the skin and bones. However, seafood is very good for you overall, so it is not recommended that you reduce the amount of seafood in your diet.

Pesticide residues on fruit and vegetables also contain fluoride, so you could consider eating organic fruit and vegetables, though these are more expensive. (The Soil Association can provide a directory of organic food suppliers - see page 21.) A new study from the American Academy of General Dentistry found that more than half of fruit juices had fluoride levels that it thought were too high. Again, the researchers did not name brands. The study blamed fluoridated water, used in making the juices, as well as pesticide residues on fruit.

Drinking artificially fluoridated water is thought to increase fluoride in the diet by more than half. If you live in a fluoridated area (see page 9), you could drink bottled water. Any fluoride content in bottled water should be detailed on the label.

Fluoride in dental products

To avoid fluorosis, it is particularly important to be cautious about fluoride in dental products used by children. The dental textbook Essentials of Dental Caries by Edwina A M Kidd and Sally Joyston-Bechal (Oxford University Press, Second Edition 1997, £27.50), gives the following advice for parents.

• Always supervise young children cleaning their teeth, ensuring they do not swallow toothpaste or any other dental product (such as mouth rinses) containing fluoride.

• Use a pea-sized amount of low-fluoride toothpaste. Those with 500 to 600 parts per million are designed for children.

• Do not give children fluoride supplements (with rare exceptions - consult your dentist if you are concerned).

• Do not use fluoride supplements during pregnancy.

Fluoride toothpaste and other dental products should be kept out of the reach of young children.

The authors say that it is regarded as safe for children over eight to use 'family' toothpaste with more fluoride. Children over six can use mouth rinses containing fluoride provided they spit it out properly.

Though there has been no research on the amount of fluoride that is taken in from toothpaste (through the mouth lining as well as by swallowing), toothpaste is accepted to be the main non-dietary source of fluoride. So if you are worried about your fluoride intake - because you live in a fluoridated area, for example - you could consider using non-fluoride toothpaste (which is more expensive than toothpaste with fluoride). You could also avoid mouth rinses and other dental products with fluoride.

The British Dental Association believes that fluoride has been the main cause of the dramatic decline in tooth decay over the past two decades. It therefore strongly supports the addition of fluoride to our water supplies. One in ten Britons currently live in areas with artificially fluoridated water, and the Association aims to make this one in four by  the year 2000.

The Department of Health says fluoridation is safe. Nevertheless, a growing amount of research suggests that increasing our fluoride intake could damage health, affecting the bones, the immune system and even mental development.

This booklet summarises startling revelations about the history of fluoridation and presents the evidence on both sides of the fluoride debate. It also details some surprising sources of fluoride and suggests what you can do to minimise any risks.

*Finally, if you want to find out more, it tells you how to go about it.

ISBN: 1 85144 196 4

*Note: these sources have been omitted