Over 60 years of international and New Zealand research tells us that water fluoridation is safe and effective in reducing tooth decay.
The evidence is clear that there are no significant adverse effects from community water fluoridation at the levels used in Aotearoa New Zealand, and that it is beneficial to New Zealanders of all ages. This is especially true for our most vulnerable people and communities.
Many countries such as New Zealand, Australia, Ireland, Canada and the United States have natural levels of fluoride that are not high enough to provide oral health benefits. As a result, these countries have been using water fluoridation to ‘top up’ fluoride to optimal levels at many of their water supplies for more than 60 years.
Hear from trusted New Zealand health professionals about the facts and benefits of this important health measure:
Efficacy and safety of water fluoridation
Review by the Prime Minister’s Chief Science Advisor and the Royal Society of New Zealand Te Apārangi
This comprehensive review of the scientific evidence for and against the efficacy and safety of fluoridation of public water supplies undertaken in 2014 concluded that:
“From a medical and public health perspective, water fluoridation at the levels used in New Zealand poses no significant health risks and is effective at reducing the prevalence and severity of tooth decay in communities where it is used. Communities currently without CWF [community water fluoridation] can be confident that this is a safe option that is cost saving and of significant public health benefit – particularly in those communities with high prevalence of dental caries.”
The Prime Minister’s Chief Science Advisor further noted that:
“It is absolutely clear that at doses used in New Zealand to adjust the natural level to one that is consistent with beneficial effects (0.7–1.0ppm), there is no risk from fluoride in the water.”
“Our assessment suggests that it is appropriate, from the scientific perspective, that fluoridation be expanded to assist those New Zealand communities that currently do not benefit from this public health measure – particularly those with a high prevalence of dental caries.”
Read the full review on the Prime Minister's Chief Science Advisor website.
Fluoridation is safe for babies and pregnant people
The scientific evidence shows that community water fluoridation is safe for everyone, including babies and pregnant women.
The comprehensive review by the Prime Minister’s Chief Science Advisor and Te Apārangi noted that typical fluoride intake levels are considered safe for pregnant women.
Similarly, typical fluoride intakes from formula feeding using fluoridated water are safe, and there is no evidence of any adverse effects on infant health or child development aside from a possible greater risk of dental fluorosis. This is a superficial condition that makes the teeth look whiter than normal speckled enamel, and recent evidence from Australia indicates that this fades with time.
Myths about water fluoridation
A number of unsubstantiated claims have been made that fluoridation causes or contributes to various health conditions or interferes with natural bodily functions. These claims have not been substantiated by experimental studies or epidemiological analyses.
The Prime Minister’s Chief Science Advisor and Te Apārangi concluded following their 2014 report that:
“No effects on brain development, cancer risk or cardiovascular or metabolic risk have been substantiated, and the safety margins are such that no subset of the population is at risk because of fluoridation.”
“We conclude that the scientific issues raised by those opposed to fluoridation are not supported by the evidence.”
The only known side-effect of fluoridation at levels used in New Zealand is mild dental fluorosis which can makes teeth look speckled or whiter than normal. However, there are no reported cases of disfiguring fluorosis associated with the fluoridating of water supplies in New Zealand. The Prime Minister’s Chief Science Advisor noted that:
‘One side-effect of fluoride is for a portion of the population it causes minimal white mottling of the enamel...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.’
Monitoring water fluoridation levels in New Zealand
The Good Practice Guide for Fluoridation of Drinking Water Supplies in New Zealand sets out how water fluoridation plants should be designed and operated to ensure the safe and effective addition of fluoride to drinking-water supplies.
Water treatment plants are monitored regularly to ensure fluoride concentrations do not exceed the maximum acceptable level set out in the Drinking Water Standards for New Zealand (ie, 1.5mg per litre). Any exceedances must be reported to Taumata Arowai (the water services regulator).
Manatū Hauora is also developing a monitoring process to ensure fluoride levels align with the optimum dose.
See the Water Services (Drinking Water Standards for New Zealand) Regulations 2022
Community water fluoridation is affordable
Community water fluoridation is also significantly more cost effective than other public health measures aimed at improving oral health.
Sapere Research Group report
The Sapere Research Group was commissioned by Manatū Hauora – the Ministry of Health in 2015 to examine the benefits and costs of water fluoridation.
The Sapere Report reviewed evidence found in numerous New Zealand and international studies and reports. It estimated the benefit of water fluoridation as follows:
- 40 percent lower lifetime incidence of tooth decay among children and adolescents,
- 48 percent reduction in hospital admissions for the treatment of tooth decay among children aged 0-4 years,
- 21 percent reduction in tooth decay among adults aged 18–44 years,
- 30 percent reduction in tooth decay among adults aged 45 years and over.
Key conclusions of this independent report were that:
“A large body of epidemiological evidence over 60 years, including thorough systematic reviews, confirms water fluoridation prevents and reduces dental decay across the lifespan.”
- “We estimate that adding fluoride to New Zealand’s water treatment plants classified as medium (i.e. those supplying populations over 5,000), is cost-saving; and for those plants classified as minor (i.e. those supplying populations over 500) it is likely to be cost-saving.”
“Because of the increased amount of dental decay among Māori and those who are most deprived, we expect these groups to have a greater absolute benefit from water fluoridation.”
The Sapere report also estimated the average ongoing cost of community water fluoridation is just $2.60 per person per year for water supplies that serve populations of over 500 people and that every dollar spent on water fluoridation will save around $9 in dental care costs. These savings will mostly benefit individual New Zealanders needing to pay for fewer fillings and tooth extractions.
Cost of fluoridation approx. $2.60 per person per year (Sapere Research Group, 2015)
$250: Average cost of a single filling for an adult (Sapere Research Group, 2015)
Read the full Sapere report together with a further district-level evaluation:
Organisations that endorse community water fluoridation include:
- Manatū Hauora – the Ministry of Health
- World Health Organization (WHO)
- The New Zealand Dental Association
- New Zealand Medical Association
- Public Health Association of New Zealand
- New Zealand Nurses Organisation
- Te Ao Marama – The New Zealand Māori Dental Association
- Toi Te Ora – Public Health Service
- New Zealand College of Public Health Medicine
- NZ Oral Health Association
- NZ Oral Health Clinical Advisory Network
- New Zealand Society of Hospital and Community Dentistry
- New Zealand Rural General Practice Network
- Office of the Children’s Commissioner
- Whānau Awhina Plunket
- Paediatric Society of New Zealand
- Agencies for Nutrition Action
- British Dental Association
- British Medical Association
- Australian Dental Association
- Australian National Health and Medical Research Council
- Department of Health, Victorian Government, Australia
- US Surgeon General
- American Dental Association
- Centre for Disease Control and Prevention (USA)
- FDI World Dental Federation
- Specialist Paediatric Dentists New Zealand
- Australia and New Zealand Society of Paediatric Dentistry.