Why Australia’s water fluoridation guidelines are under review

Australia’s top medical research agency will review the nation’s guidelines for fluoride in drinking water as new studies linking prenatal exposure to lower intelligence in children reignite debate about the public health measure.

The National Health and Medical Research Council, which currently advises that it’s safe for pregnant and breastfeeding women to drink fluoridated water, confirmed the review on Thursday.

“We will undertake a comprehensive review of the available evidence at this time and look to see what has emerged,” the council’s acting chief executive, Prue Torrance, told a Senate hearing.

She was responding to a question from South Australian Liberal senator Alex Antic, who asked if the advice would be reviewed in light of research indicating that fluoride crossed the placenta and was linked to “adverse neurodevelopmental outcomes”, including reduced intelligence in children.

The hardline conservative politician has previously been condemned for spreading “dangerous” ideas about vaccination and has spoken on an online radio station that publishes documentaries about the dangers of fluoride in drinking water.

Australian Dental Association vice president Dr Angie Nilsson said an overwhelming weight of evidence showed that fluoridated water was a safe public health measure that reduced tooth decay.

She referred to a 2025 longitudinal study that found no difference in the IQ of Australian children who were exposed to fluoride during early childhood and those who weren’t.

She said Australian guidelines strictly controlled water fluoridation well within safe limits recommended by the World Health Organisation.

“It is actually a really alarming thing when someone’s saying to a pregnant woman, ‘you shouldn’t be having fluoridated water’,” she said.

Nilsson welcomed the upcoming review, saying it would add to the weight of evidence supporting fluoridated water and ensure there was trust in the public health measure.

“We’re in a society now where there’s a lot of alarmist views, and people look into information that isn’t necessarily evidence-based,” she said.

Nilsson, who works in public dentistry in northern NSW, regularly treats extensive tooth decay in children whose families avoid fluoride. This includes children in the Byron Bay Shire, which does not add fluoride to its urban water supply as a result of long-standing community opposition to fluoridated water.

“It’s decay that leads to pain and abscesses, that leads to a general anaesthetic and having all of their baby teeth – 20 teeth – taken out in one hit because they’re rotten,” she said. “It’s just heartbreaking.”

Since the 1960s, fluoride has been added to Australia’s public water supplies (0.6 to 1.1 milligrams per litre) to reduce tooth decay – one of the nation’s most common health problems.

The National Health and Medical Research Council currently advises that Australia’s fluoridated water consumed by pregnant and breastfeeding women is safe for their unborn babies and infants based on a 2016 review of the scientific research.

Breast milk naturally contains about 5 to 10 micrograms of fluoride per litre of milk, and the level of fluoride in breast milk remains steady when a nursing mother drinks fluoridated water, the council advises.

But fluoridated water has been a lightning rod of conspiracy theories, from government mind control to objections that fluoride is an unnatural additive.

International consensus among researchers and major international public health bodies is that there is a lack of evidence to support a causal link between fluoridated water in pregnancy and lower intelligence in children, noting conflicting findings and significant limitations of some studies’ design.

The US Environmental Protection Agency is planning a review of fluoride in drinking water under Secretary of Health and Human Services, Robert F. Kennedy Jr.

“A growing body of evidence indicates that ingesting fluoride can cause neurological harm, and other adverse effects,” said Kennedy, who has falsely linked autism to vaccines and paracetamol in pregnancy, and chemicals in the water supply to gender dysphoria, and rejected scientific evidence that HIV infections cause AIDS.

Dr Ian Musgrave, a molecular pharmacologist and toxicologist at the University of Adelaide, said: “It’s a very, very emotional issue, and unfortunately actual facts are rarely used.

“What we do know is that [fluoride] at concentrations that are used in potable water in Australia, Europe and the US, there doesn’t seem to be any effect on IQ in kids,” Musgrave said, citing studies that accounted for numerous confounding factors.

He said the limitations of studies showing fluoride in drinking water was linked to lower intelligence in children “mean that you really can’t take this incredibly seriously”.

Several large studies have concluded that consuming fluoride at recommended levels has no adverse effects, including a 2025 US study involving 26,820 school students, some of whom were followed up 40 years later.

Epidemiologists point to large multi-decade population data that show no widespread decline in childhood intelligence in countries after they introduced fluoridated drinking water, and that IQ scores trended up slightly over time.

A 2022 study involving 2700 Australian children also found no evidence of a link between fluoride and IQ, with a 2025 Australian study reaching a similar conclusion.

But other recent studies have prompted calls for agencies to review their advice, particularly for pregnant women.

A 2025 study by Swedish researchers involving 500 mothers and their children in Bangladesh found that low exposure to fluoride during pregnancy was linked to subtle declines in children’s intelligence at five and 10 years old.

A 2024 systematic review by the US National Toxicology Program concluded with moderate confidence that there is some evidence of an association between lower IQ in children and exposure to high levels of fluoride – above WHO-recommended levels of 1.5mg per litre, well above the fluoride concentration in Australia’s drinking water.

The researchers pointed out that a drop of just a few IQ points would not be easily noticeable in an individual child, and was no great detriment to them, but it was notable for public health experts, given that at a population level, it may increase the number of children who may need additional education support.

A National Health and Medical Research Council spokeswoman said the expert body monitored emerging evidence and periodically reviewed its health advice to ensure it was current.

“The review will be informed by systematic reviews of the literature, including consideration of recent international studies, to ensure it continues to reflect the best available scientific evidence,” she said.

She said an expert committee would advise on the scope and research questions of the review, including the populations and health outcomes to be considered.

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