The longstanding public health practice of adding fluoride to community drinking water is facing heavy scrutiny in the United States over questions about whether the benefits outweigh the potential risks. But new research challenges recent claims about the risks of fluoride in drinking water – and rather suggests that it may have additional positive effects.

The heightened federal debate was spurred by a recent goverment study from the National Toxicology program that concluded that high levels of fluoride exposure are linked to lower IQ in children, but that study evaluated fluoride exposures that where at least twice the federally recommended limits with notably “insufficient data” to determine the effects of lower levels.

The new study looked at more typical, recommended levels of fluoride in drinking water and instead found “robust evidence” that young people exposed to fluoride at these lower levels actually performed better on ​cognitive tests than their peers who did not have fluoride in their drinking water.

Dr. Rob Warren, lead author of the study published in the journal Science Advances on Wednesday, said he was “shocked” by the findings from the National Toxicology Program study and motivated to provide research that was more relevant to public policy decisions.

“I wouldn’t have done this work had it not been an empirical question that I didn’t think we had an answer to, of great immediate policy interest,” he said.

US Department

Study Finds No Link Between Fluoride in Drinking Water and Lower IQ in children

A new study published Monday in the journal Environmental Health Perspectives suggests that fluoride added to public drinking water does not negatively impact children’s cognitive advancement. The research, which followed over 300 mothers and their children from six cities in Canada – some with fluoridated water and some without – tracked cognitive test scores from ages 3 to 12.

Researchers found no statistically meaningful difference in cognitive scores between children who grew up drinking fluoridated water and those who did not. The study builds on previous research, including a 2015 National Research Council review that found limited evidence of an association between fluoride and cognitive function. This latest analysis continued to follow participants even when most had reached 60 years of age, and suggested that fluoride exposure also did not contribute to cognitive decline as participants aged.

Cognitive tests are not direct measures of IQ. There is a strong correlation, says study author Dr. Christine Warren, but cognitive tests measure a mix of how well someone’s brain works along with the opportunities they’ve had to learn the material. She’s working on additional research that will directly assess the link between fluoride and IQ, with more precise measurements and data about where the individuals lived during childhood, too.

Other research from this year estimated that removing fluoride from public water in the US would lead to 25.4 million excess decayed teeth in children and adolescents within five years, along with $9.8 billion in health care costs. The new study did not measure individual dental health, but experts say that pain from tooth decay can cause children to have trouble focusing in school or miss it wholly – which could be a factor affecting cognitive test scores.

Fluoride is a mineral that can be found naturally in some foods and groundwater. It can help prevent tooth decay by strengthening the protective outer layer of enamel that can be worn away by acids formed by bacteria,plaque and sugars in the mouth. The practice of adding fluoride to public water systems started in the United States in 1945 to help improve oral health in a cost-effective and equitable way.

The American Dental Association and manny experts have continued to support the practice of community water fluoridation, and the US Centers for Disease control and Prevention has not changed its recommendations. The agency cannot mandate that communities add fluoride to their water, but it considers 0.7 milligrams of fluoride per liter of water to be the optimal level for preventing tooth decay.