On the first day of Donald Trump’s presidency, Robert F. Kennedy Jr. said he would advise Trump to remove fluoride from public water. The former independent presidential candidate – and prominent supporter of public health claims debunked — was told he would be put in charge of health care initiatives in the new Trump administration. He described fluoride as an “industrial waste.”

Here’s what scientists say and what we know about fluoride in drinking water in Canada.

What is fluoride?

Fluoride is a natural mineral released from rocks into soil, water and air.

It is commonly used in dentistry to strengthen tooth enamel and prevent cavities.

In many parts of the world, including Canada, public health authorities or local governments add it to the drinking water supply to help prevent tooth decay in the community.

Leading public health organizations around the world, including the World Health Organization and the Public Health Agency of Canada (PHAC), support this practice. PHAC states that fluoridation is associated with 25 percent off in tooth decay in children and adults. In the United States, the Centers for Disease Control and Prevention has designated it as one of the good public health achievements of the 20th century.

In Canada, 38.8 percent of the population has access to fluoridated water, according to PHAC. Access varies among provinces and territories, depending on several factors such as cost, infrastructure and community concerns.

But some have questioned this practice: from a debunked point of view conspiracy theory of a communist plot in the 1950swhether fluoridation is effective enough to justify its costs.

Many of the concerns — including those raised by Kennedy during the U.S. election campaign — are not based on sound science, says Gerry Uswak, director of the dental therapy program at the University of Saskatchewan.

“Nonscientists interpret scientific data and make policy decisions based on emotion, not objectivity,” he said.

What are the risks?

Excessive fluoride ingestion over a long period of time can lead to skeletal fluorosis, a bone disease that can cause bone pain and deformity. The condition is extremely rare in Canada, because health authorities adjust fluoride levels in water to ensure its safety.

Another slight risk for children according to Health Canada is dental fluorosis. Children who ingest more fluoride than recommended (for example by swallowing toothpaste) may develop white spots on the surface of their teeth, but there are no other symptoms or harm associated with this condition.

Aaron Burry, CEO of the Canadian Dental Association, says he is prepared to change his recommendation on water fluoridation if the science warrants it. But for now, he’s not convinced the risks outweigh the benefits.

“We look at all the published research every year. And so far we haven’t seen anything that…is concerning,” he said.

Is there an impact on young brains?

Some scientists have recently studied a possible link between fluoride and intelligence in children.

A 2019 study published in JAMA Pediatrics suggests an association between lower IQ scores in Canadian children aged three to four and the level of fluoride consumed by their mothers during pregnancy. The study did not establish causality (other factors could be at play besides fluoride) and its methods and conclusions were also widely criticized at the time.

“This is not to say that fluoride during pregnancy definitely has no effect on IQ – but it is far from clear that this is the main explanation for these relatively small differences in IQ,” said Kevin McConway, Emeritus Professor of Applied Statistics at the Open University. in the United Kingdom

Upon publication, the journal’s editor-in-chief explained his decision to publish the article, emphasizing the importance of examining any possible links between fluoride exposure and cognitive development.

“Scientific research is an iterative process,” Dr. Dimitri Christakis wrote in the editor’s note.

“It’s rare for a single study to provide definitive evidence.”

Christine Till, one of the study’s authors and a professor of psychology at York University, says there isn’t enough evidence of a link at lower levels of exposure, such as those currently recommended for drinking water in the United States and Canada.

“We don’t have as many studies in this area. We need more studies and replications,” Till said.

Another report published this summer by the US National Toxicology Program, also examined the impact of all sources of fluoride exposure, such as food, water or toothpaste, on pregnant women, infants and children . This suggests that high exposure levels – 1.5 milligrams per liter – are associated with lower IQ in children. This is more than double the recommended water concentration in Canada, which is 0.7 milligrams per liter.

A recent goodbye High-quality studies on the subject—published by Cochrane, an international network of health professionals that reviews health research—suggest that although fluoride in water causes fewer tooth decay in children, the benefits could be less than before the addition of fluoride to the water. most toothpastes.

That’s no surprise, Burry said. He says water fluoridation is “one tool among a whole range of tools” to ensure the dental health of Canadians.

Uswak says those who cannot afford to see a dentist are likely to suffer the most without fluoridation.

“The people in society who face the greatest number of barriers to accessing care benefit the most from community water fluoridation.”