Study finds fluoride in water does not affect brain development

A University of Queensland study has found no link between exposure to water fluoridation as a young child and negative cognitive development.

Professor Loc Do from UQ’s School of Dentistry said the IQ scores of 357 people who had participated in the 2012–2014 National Child Oral Health Study were assessed by registered psychologists to see if their exposure to fluoride as a young child impacted their brain development.

With the participants now aged 16 to 26 years old, we found those who’d consistently been drinking fluoridated water had an IQ score 1.07 points higher on average than those with no exposure,” Professor Do said.

“We also found people who had dental fluorosis – a reliable biomarker related to excessive fluoride intake in early childhood – had IQ scores 0.28 points higher on average than those without.

“Factors which may affect the relationship between fluoride and IQ, such as socioeconomic status, were taken into account when determining the results.”

“There have been claims water fluoridation can negatively affect children’s neurodevelopment, but these results provide consistent evidence this is not the case.

“Water fluoridation, as practiced in Australia, is safe for children’s development.”

Co-author Dr Diep Ha said water fluoridation was highly effective in preventing dental decay.

“Approximately 90 per cent of the Australian population has access to water fluoridation, but many regional and remote areas are not covered,” Dr Ha said.

“Dental decay or cavities are the most common chronic childhood disease worldwide, which can be quite painful, and teeth often have to be removed.

"Fluoridation is very effective in preventing these issues, and this research provides reassurance that it is safe to be expanded into more communities.”

This study is the second phase of research conducted by Professor Do’s team – the first phase found no difference in behavioural development and executive functioning in children exposed to fluoridated water compared to those who had no exposure.

The research is supported by a National Health and Medical Research Council (NHMRC) grant.

Collaborators include experts in dental research, psychology, toxicology and biostatistics from the University of Adelaide, Queensland Health and Bristol University, UK.

The research is published in the Journal of Dental Research.