The Calgary Eyeopener was flooded with calls this week from listeners voicing their concerns and questions about the possible health risks of fluoridated drinking water.

The debate over whether fluoride should be added to our drinking water was revived by a new University of Calgary study.

The report says there's been a jump in tooth decay among children, since fluoride was removed from the city's water supply in 2011.

Eyeopener host David Gray interviewed Alison White, a science educator at Telus Spark, to address those concerns.

What is fluoride, exactly?

Alison White

Alison White, a science educator at Telus Spark, says there is some misinformation circulating online about fluoride. (Cassondra Dickin/Telus Spark)

Fluoride is a charged particle (aka anion) of a naturally occurring element called fluorine, which is the 13th most abundant element in the world.

In other words, White explained, it's everywhere. 

"Because of that charge on it, fluorine naturally hugs other elements in nature ... it's normally found with other things in minerals — it's in earth's crust, in rocks, in water, in the air."

Is fluoride a drug?

"That is a good question," responded White.

"You can compare it with adding iodine to salt. We don't see a lot of people with goiters anymore, and that's largely due to iodine being added to our foods and other things," she said.

"Fluoride isn't needed by, say, our thyroid in the same way that iodine is, but I wouldn't say it is a drug."

Is fluoride a chemical?

Yes, White said, "but in the same way that water is also a chemical, it's made up of molecules."

Fluoride occurs naturally at certain levels in Calgary, and the normal natural levels depend on the location.

"In some parts of the world [fluoride] is found in much higher quantities," said White. "And that's where you do get into some trouble as with anything … quantity and concentration matters based on the best available scientific evidence."

What does the scientific research say?

Adding fluoride to public drinking water has been going on since the 1940s when U.S. cities started adding it to the drinking water.

White said research accumulated by Health Canada, U.S. Center for Disease Control, World Health Organization and others has not linked any negative health outcomes with fluoridating drinking water to recommended levels.

If fluoride is safe?

"Eating a big glob of toothpaste, you wouldn't want to be ingesting that every day, probably because of the fluoride, but also because of all the other things in there," answered White.

She likened it to chlorine in the water supply.

"You wouldn't want a really high amount of chlorine in there, but a certain amount keeps our water safe for us to drink."