The Australian Science Media Centre has gathered experts in the fields of chemistry, dental science, water quality and ethics to discuss the science of fluoridation and examine the basis of concerns expressed by the public about the practice.
Four experts spoke at an online briefing on 17th December and further comments from a variety of experts are available below.
Queensland is the last State in Australia to introduce fluoridation to its water supplies, introducing the Water Fluoridation Bill in early 2008. Under this legislation public water suppliers who supply water to over 1000 people, must add fluoride to the public water supply.
In December 2008 several South East Queensland water treatment plants, Mudgeeraba, Molendinar, Mt Crosby, North Pine and Landers Shute, began supplying fluoridated water to the surrounding areas. In November 2009 Gladstone also began supplies while earlier this month around a dozen other small water treatment plants in SEQ and Yarwun (outside Gladstone) also came on line.
Within a week Mackay, Rockhampton and Cairns are also expected to supply fluoridated water from their major water treatment plants. By 2012 the Queensland Government aims to provide 90 per cent of Queenslanders with fluoridated drinking water.
The briefing discussed:
- The impact of fluoride on dental health in children and adults
- The metabolism of fluoride in the human body
- Water quality and safe levels of fluoride
- The ethics of adding fluoride to water
Dr Stuart Khan, Senior Research Fellow at the UNSW Water Research Centre at the University of New South Wales – What is fluoride and what level is safe for human consumption?
Listen to Stuart (mp3)
Stuart’s presentation (pdf)
Associate Professor Mark Gussy, Deputy Head of the School of Dentistry and Oral Health at La Trobe University – How does fluoride impact on the dental health of kids and adults?
Listen to Mark (mp3)
Mark’s presentation (pdf)
Professor Colin Rix, Adjunct Professor of Applied Chemistry at RMIT – What happens to fluoride in the body?
Listen to Colin (mp3)
Dr Linda Barclay, The Centre for Human Bioethics, Monash University – the ethics of adding substances to the water supply.
Listen to Linda (mp3)
The National Health and Medical Research Council reviewed the scientific literature on fluoride in water and produced this public statement in late 2007.
GreenFacts.org is an independent non-profit organization with a non-advocacy policy. They produced a comprehensive resource on fluoride based on information from the WHO International Programme on Chemical Safety.
Roundup of comments:
The Australian Science Media Centre has rounded up the following comments from experts who have published on fluoride in Australia.
Associate Professor Neville Hicks is an Associate Professor of Public Health at the University of Adelaide
“Fluoridation of water supplies has been suggested many times in South Australia because there was a natural experiment in that State from the mid-1940s.
Children who were in utero at Port Lincoln, on Southern Eyre Peninsula, where the Yuley Basin underground supply is naturally fluoridated grew up to have minimal tooth decay in childhood and sound (secondary) teeth in adulthood. Children who grew up in the Riverland, where the Murray river supply was not fluoridated grew up with greater levels of decay.
In one sense, this was a ‘natural experiment’ – if you grew up there you got fluoride on Eyre Peninsula; if you grew up in the Riverland, you didn’t get fluoride – until…
The data on decay from the two districts was the justification for the fluoridation of water in South Australian, more generally (and decay rates among S.A. children, overall, declined in the generation and a half after 1950. (If you didn’t have access to fluoridated water, fluoride tablets were the alternative.)
There is not, to my knowledge, compelling data that there were statistically adverse effects of the ‘natural’ fluoride intake on Eyre Peninsula compared with the ‘artificial’ fluoridation in areas watered from the Murray Basin. The exception may have been some cosmetic deficit among the tablet takers.
When Queensland, later, began adding fluoride to parts of its water supply there were some complaints that this was against God or an interference with Nature but the few epidemiological studies that I have seen do not sustain those complaints.
As to the (suggested) moral argument that parents purveying fluoride tablets to children are acting ‘against nature’ or ignoring the rights of the children, two responses might follow. (1) Giving your children fluoride tablets or carefully fluoridated water is not different from teaching them to swim; the hazards from either practice are slight and the dental health benefits appear to be considerable. (2) In what way is attending to your children’s health, according to reasonably based evidence, different from attending to their social and moral development? Both programs are part of the moral practice of ‘good parenting’, according to the evidence available.”
Dr Meenakshi Arora is a Research Fellow for Chemical and Biomolecular Engineering at the University of Melbourne
“I totally agree with the concept of fluoridation of drinking water as it definitely and significantly reduces the risk of dental caries. But we need to be careful not to overdose people, especially kids in the age range of 2-7 years, because excess fluoride may become part of the tooth matrix of kids at the time permanent teeth are being formed leading to incurable dental fluorosis.
People should be aware of the levels of fluoride in toothpastes and other food sources while drinking fluoridated water. Also, one might consume more water on a hot summer day and so more fluoride as compared to a cold winter day.
I totally endorse the decision of fluoridating Queensland water supply. Educating people a bit more about fluoride management would warrant the achievement of desired goals, though.”
Associate Professor Stephan Millett is Director, Centre for Applied Ethics and Philosophy at Curtin University of Technology
On the ethics of adding fluoride to water supplies:
“Those who oppose fluoridation have a right to opt out and buy bottled water or install a water filter, but the society as a whole has an obligation to ensure preventable harms are prevented. This is the crux of the social contract for civil societies.
If we know that adding something safe to a public commodity will reduce harm, reduce health costs and improve quality of life for the population as a whole, we have an obligation to do it. We put street lights, traffic lights and stop signs on roads. We put catalytic converters on cars to limit pollution. We require people to wear seatbelts. And we add folate to bread to prevent neural tube defects such as spina bifida. In each case both potential harms to individuals and various forms of costs to the society are reduced.
Claims actions such as these, taken in support of the public good, are somehow a violation of rights are wrong-headed. A society has an obligation to ensure the welfare of its citizens. And members of a society have an obligation not to burden others with avoidable costs.”
Professor John Spencer is Director of the Australian Institute of Health and Welfare Dental Statistics and Research Unit and Head of the Dental Practice Education Research Unit at the University of Adelaide
“People in northern Queensland are about to join over 80% of Australians who have access to fluoridated water supplies. Fluoride deficient water supplies have fluoride added to achieve a concentration of between 0.6 and 1.1 mg/litre of water. Northern Queensland will be fluoridated at 0.6 to 0.7 mg/litre.
Fluoridation of water supplies has been described as one of the 10 most important public health measures in the 20th century (1). Australia has pursued the fluoridation of water supplies as an effective public health measure to reduce dental decay. While most of the evidence for this is focused on children (2,3) its benefits have also been documented among younger adults (4).
A number of Australian health authorities have recently supported the effectiveness and safety of fluoridation. In 2007, the National Health and Medical Research Council (NHMRC) published a systematic review of the efficacy and safety of water fluoridation (5). That review led to an NHMRC public statement that supports fluoride in the prevention of dental decay and its safety (6). More recently Food Standards Australia and New Zealand (FSANZ) examined the voluntary addition of fluoride to packaged water. After consideration from that organization’s perspective of the equivalency of fluoridated packaged and reticulated water supplies, FSANZ has supported the addition of fluoride to packaged water and stated that there is a history of safe use of fluoride in reticulated water supplies.
Groups representing consumers have also reached the same conclusions about the benefits and safety of fluoridation. The Australian Consumers’ Association stated in Choice in 2007 that there’s now solid scientific evidence that fluoride added to drinking water helps to protect your teeth from decay, the claims of those who oppose fluoridation are often based on outdated information, questionable research and selectively picking studies that support their case, there’s no convincing evidence for harmful effects from fluoride at the levels used in our water supply (8).
Australia has had a long-term experience with the fluoridation of water supplies. It is over 50 years ago that Beaconsfield in Tasmania was the first site to fluoridate. Most capital cities fluoridated across the 1960s and early 1970s. The outcome has been monitored ever since, with periodic major reviews. The millions of Australians living in fluoridated areas have not shown adverse health effects. On-the-other-hand Australian children’s experience of dental decay is among the lowest of our comparable countries. New research continues to document benefits for oral health. For instance, Spencer, Armfield and Slade (2008) have reported the lower initiation of new decay over a three-year follow-up period and Liu, Spencer and Do (2008) have reported on the longer survival free of decay of key teeth like the 6-year-old molars in South Australian and Queensland children who have spent more of their life in a fluoridated area.
Australian researchers have been among the leaders in ensuring that policy on the use of fluoride is achieving the greatest reduction in dental decay without any adverse effects (11). Fluoridation is the centerpiece of the use of fluoride to prevent decay. It stands out as a public health measure in that it is not only beneficial and safe, it is also socially equitable (those most in need benefit most) and efficient (low cost for the benefit).
The extension of the fluoridation of water supplies in Northern Queensland allows more Australians to improve their oral health. As a result fewer children and young adults across the next decade or so will experience the pain of a toothache and the anxiety and discomfort of its treatment. For some this includes hospitalization and general anesthetics for complex treatment. Avoiding such preventable disease and suffering is a boon for children, parents and the community.”
1. Centers for Disease Control and Prevention. Ten great public health achievements of the 20th Century MMWR 1999; 48(41): 933-940.
2. National Health Service, Centre for Reviews and Dissemination. A systematic review of public water fluoridation. York: NHS Centre for Reviews and Dissemination, University of York, 2000.
3. McDonagh MS, Whiting PF, Wilson PM, Sutton AJ, Chestnutt I, Cooper J et al. Systematic review of water fluoridation. Br Dent J 2000; 321:855-9.
4. Griffin SO, Regnier E, Griffin PM, Huntley V. Effectiveness of fluoride in preventing caries in adults. Evid Based dent 2007; 8: 72-3.
5. National Health and Medical Research Council. A systematic review of the efficacy and safety of fluoridation. Canberra: NHMRC, 2007a.
6. National Health and Medical Research Council. Public statement on the efficacy and safety of fluoridation 2007. Canberra: NHMRC, 2007b.
7. Food Standards Australia and New Zealand. Voluntary addition of fluoride to package water. Final Assessment Report. 6 May 2009. Accessed at www.foodstandards.gov.au/standardsdevelpoment/on 16/12/2009.
8. The evidence for fluoride. Choice 2007 March: 25-27.
9. Spencer AJ, Armfield JM, Slade GD. Exposure to water fluoridation and caries increment. Community Dent Health 2008; 25: 12-22.
10. Liu P, Spencer AJ, Do L, Armfield J: Dental caries events by exposure to fluoridated water – a survival analysis. Presentation to the Population Health Congress 2008, Brisbane, 2008. Accessed at www.arcpoh.adelaide.edu.au/publications/presentations on16/12/2009.
11. Australian Research Centre for Population Oral Health, The University of Adelaide. The use of fluorides in Australia; guidelines. Aust Dent J 2006; 51: 205-11.
Dr Mark Diesendorf is the Deputy Director of the Institute of Environmental Studies at the University of New South Wales
“Fluoridation of drinking water should be terminated, because it is unsafe, ineffective and unethical. It is unsafe because it causes skeletal fluorosis, a disease of bones and joints that manifests as arthritis in the early stages, but can evolve over decades into abnormal bone growth and calcification of joints.
Animal studies and an epidemiological study on humans suggest that fluoride ingestion in childhood may be a causal factor in osteosarcoma (bone cancer) in young men. There is also evidence that a small minority of people suffer hypersensitivity reactions to ingested fluoride.
There is no scientific evidence that ingestion of fluoride reduces dental caries. High concentrations of fluoride in toothpaste do reduce caries by action on dental surfaces, but this says nothing about the effectiveness of low concentrations in fluoridated water. Since fluoride is not an essential nutrient, fluoridation is mass medication with an uncontrolled daily dose and so is a violation of medical ethics.”
Dr Ray Mullins is a Canberra-based clinical immunology and allergy physician.
On the question of fluoride causing allergies:
“With the exception of high-dose gaseous fluoride in aluminium smelters (which has been associated with respiratory symptoms from irritant effects), I cannot find a single case report to suggest that allergy or asthma in response to fluoride in water has occurred. If an individual is suspicious of such an effect, it is likely to have another explanation and they should seek review from their usual medical adviser. Fluoride has a number of beneficial public health effects, whereas evidence of toxicity in normal concentrations in water is poor and evidence of allergy is non-existent.”
Professor Colin Rix is an Adjunct Professor of Applied Chemistry at RMIT
On fluoride’s enzyme-inhibiting potential in humans:
Yes, fluoride is an enzyme inhibitor– it is believed that this effect contributes to some of the cariostatic control by which fluoride protects teeth, as bacteria attack the surface of a tooth, fluoride is released which can inhibit some enzymes, so killing the bacteria.
Certainly the effect of fluoride depends on the dose, and the type of enzyme; I would suggest it is only the 30% or so metal-containing enzymes that might be affected, as fluoride could bind to the metal at the active site, causing it to cease functioning. In the body this does not occur, as the concentration of free fluoride is simply too low in plasma, but high concentrations could arise at the very surface of a tooth as a result of bacterial attack. Remember, fluoride is in its highest concentration at the surface of the tooth enamel– about 1000-2000 mg/kg in the 1/10 mm surface layer, dropping to 50-100 mg/kg in the interior of the tooth.
On the effect fluoride has on plants and animals in areas where fluoride is not naturally present:
Almost all the natural fluoride is bound in minerals, and not very bio-available, and generally the poorly soluble minerals do not give rise to fluoride concentrations which can interfere with plants or animals. However, around industrial sites such as aluminum refineries and cement works,(or volcanos!) airborne particulate and gaseous fluoride emissions do occur –the acidic gases eventually kill off the plants, and animals that feed on the adjacent pasture may develop fluorosis, joint stiffness and lack of mobility.
On the evidence of decay in low fluoride areas in Indigenous people in Australia pre-European settlement and if decay is related to European diet:
The generally higher level of refined sugar in our diet does give more opportunity for bacterial attack–there is some 250-300 bacteria/yeast/microbes in the oral cavity and in plaque on the teeth, that generate lactic acid during their metabolism, which accelerates decay. I don’t know if indigenous Australians used to clean their teeth with charcoal or tooth picks to remove plaque, which would limit attack.