A fresh science review has reaffirmed there's no significant health risks with levels of fluoride applied to New Zealand water supplies. Photo / Stephen Parker
A fresh science review has reaffirmed there's no significant health risks with levels of fluoride applied to New Zealand water supplies. Photo / Stephen Parker
A fresh science review has reaffirmed there's no significant health risks with levels of fluoride applied to New Zealand water supplies.
Currently, around 2.3 million Kiwis have access to fluoridated drinking water and decision-making has sat with individual councils and mayors – something that's led to some controversial calls.
The Government and health professionals have long advocated community water fluoridation as an effective, safe and affordable way to combat tooth decay, which thousands of children were admitted to hospital for in 2019.
The new review, published by the office of chief science advisor Professor Dame Juliet Gerrard this week, largely backed the conclusions of a 2014 report by Royal Society Te Apārangi, reaffirming that current levels of fluoridation were effectively safe.
"Through our research we have found the conclusions of the Royal Society Te Apārangi remain appropriate and there are no adverse effects of fluoride of any significance arising from fluoridation at the levels used here," Dame Juliet said.
"Adding fluoride to water continues to have a positive impact by reducing the incidence of dental caries in Aotearoa New Zealand and is particularly important in reducing socioeconomic health inequities."
Water fluoridation is the process of adjusting the natural level of fluoride in the water supply to between 0.7 and 1.0 parts per million - the optimal amount that provides protection against tooth decay, and recommended by the World Health Organisation.
As the current levels of fluoride found in untreated water supplies in New Zealand wasn't effective enough to be of benefit in helping to prevent tooth decay, many councils topped up fluoride levels in their supplies.
The review found that how much fluoride a person was exposed to depended on their diet, how much water they drank, the level of fluoride in their water supply, and their oral hygiene routines.
Some groups could be exposed to higher levels of fluoride than what was necessary to gain oral health benefits - particularly formula-fed infants living in areas with fluoridated water supplies.
Source / Office of the Prime Minister's chief science advisor
While that could put them at higher risk of experiencing mild dental fluorosis – a tooth enamel defect resulting in opaque white spots on the teeth - no other health concerns were expected.
And at the levels used for water fluoridation here, the effects of dental fluorosis were considered generally "mild", posing no health concern and little-to-no cosmetic concern. The review also found that incidence of dental fluorosis was generally similar between fluoridated and non-fluoridated areas.
While recent studies continued to show that, at very high levels and with chronic exposure, fluoride could potentially have negative neurodevelopmental and cognitive impacts, this also wasn't a concern at levels used here.
In contrast to a 2019 Canadian study that drew controversy and criticism, an epidemiological life course study undertaken found no evidence of IQ or other cognitive effects in children due to fluoride exposure.
Similarly, the review identified no significant risks around cancer, skeletal effects and a range of other issues with the levels of fluoridation in New Zealand.
The update comes as the Government is moving on a law change giving director-general of health Dr Ashley Bloomfield oversight for all decisions on fluoridating water supplies – and moving powers away from councils.
In March, Associate Health Minister Dr Ayesha Verrall said she expected the Health (Fluoridation of Drinking Water) Amendment Bill – first introduced in 2016 by the then National-led government – by the end of the year.
"'Topping up' fluoride levels allows the well-established health benefits to reach all New Zealanders, especially our children, Māori and Pacific populations and people in our poorer communities," she said.
