In this occasional feature, the Post tells you everything you need to know about a complicated issue. Today: Sarah Boesveld examines Calgary’s debate about removing fluoride from the city’s water.

Q: Why is Calgary talking fluoride?
A: The presence of fluoride in Calgary’s city-supplied drinking water, meant to prevent tooth decay, is one of the city’s longest running debates, having been subject to six plebiscites since 1957. Last week, Calgary alderman Druh Farrell asked council to vote fluoride out of the city’s drinking water. Ten out of 15 aldermen supported the motion, but Mayor Naheed Nenshi said he wanted public and expert consultation before making any decisions. His wish was granted Monday when, after being inundated with calls and emails from across North America, council voted to hold a day-long consultation on Jan. 26.

Q: What’s council’s take on it?
A: The public debate is a perceived win for the mayor, who last week admitted he did not have enough information to vote either way and that, because of such differing views on the subject, the public should have their say. Aldermen who wished to vote for its removal expressed frustration, saying the public forum would likely do little to change the minds of those who already supported the motion. “The purpose of having a public hearing is to become informed, and what I hear is a lot of council members saying they have the information they want,” said Alderman Gael Macleod.

Q: What have other Canadian cities done about it?
A: Last November, Waterloo voted to remove fluoride from its drinking water following a public referendum. Many cities, including Ottawa, Edmonton and Toronto, add fluoride to their water in keeping with guidelines from Health Canada. But some cities have had as much trouble trying to add it as others have had removing it. In 2005, Stephane Schwartz, associate director of the Montreal Children’s Hospital dental clinic, lobbied to increase the natural amount of fluoride in Montreal’s water supply from 0.3 parts per million to 0.7 parts per million, the quantity said to prevent cavities. “I think that when we lost the battle last time, we went back 10 years,” in terms of public acceptance of fluoridated water, she said.

Q: What’s so allegedly bad about fluoride in city drinking water?
A: Critics say overintake of fluoride contributes to health problems, with links drawn to cancer, reduced bone density and intelligence levels. Organizations such as the Fluoride Action Network have called it toxic. Many consider fluoride a medicine and believe they should be able to choose whether they ingest it (fluoride doesn’t need to be ingested to be effective, the network says). Some, including Ms. Farrell, wonder if it’s effective at all, citing research from the United States that shows cities with the worst tooth decay are also ones that fluoridate. Nutrition and dental care are much better than they were 60 years ago, when fluoridation largely began, Ms. Farrell said. Adding fluoride to city water is also expensive – it costs Calgary taxpayers approximately $750,000 a year, Ms. Farrell said.

Q: What’s so allegedly good about it?
A: Fluoridated water helps bring oral health to vulnerable populations, Dr. Schwartz said. “When you visit a family of four who live on welfare, you see what they eat and you have a bottle of Coke on the table,” she said. “[Drinking water fluoridation] is the only way you can reach this part of the population,” she said, adding that disabled people and seniors also benefit from fluoridated water and are less likely to access alternatives, such as mouthwashes and veneers. She points to the World Health Organization’s guidelines that say water fluoridation is one of the 10 most beneficial public health services for children, especially.

Q: Why is the debate so divisive?
A: The amount of evidence on both sides is ample and mounting. “There’s duelling science and both sides have stopped listening to each other,” Ms. Farrell said. She has received more than 500 e-mails, with about 80% of them in favour of removing the fluoride, she said. “When you’re talking about a health concern that’s still unresolved after 60 years, it’s really important for people to be keeping an open mind,” she said. “And with the advent of so many other alternatives, we should be looking at this with a contemporary lens.”

National Post, with files from Postmedia News