If there was any doubt about the need for City Hall to reopen the debate over how much fluoride is too much, it’s been rinsed away by a new report.

The expert panel that wrote the Health Canada report wants to reduce the amount of fluoride to which children are exposed.

The panel made three proposals to the federal government. It wants Ottawa to cut the recommended amount of the tooth-strengthening chemical added to municipal drinking water, to encourage the use of low-fluoride toothpaste by children, and to urge makers of infant formula to reduce levels in their products.

The Health Canada report adds to a growing pile of studies questioning the adverse effects of the chemical, touted as the key weapon in the fight against tooth decay, but also considered a carcinogen in humans exposed to high industrial levels.

Some aldermen have been questioning whether the city should continue to fluoridate its water, at least to the extent in which it is so doing. But the issue has proven divisive at city hall. There’s a feeling on council it should be left alone, understandably so considering the city went through five plebiscites on the issue before finally adding fluoride to the municipal water supply in 1991. Yet another plebiscite was held in 1998, at which time it narrowly passed in favour of continuing the practice.

No more plebiscites are needed. However, a review of the latest body of peer-review science is in order. It’s the health of our children in question.

A number of credible studies link excessive fluoride exposure to hyperthyroidism, lower IQs in youngsters and bone cancer in teenage boys. The panel concluded there wasn’t enough evidence to support the association with cancer or IQ deficits. It justified fluoride reduction because excessive amounts place kids at risk of fluorosis, a mottling of teeth which can lead to decay.

Who’s to say tooth enamel is the only tissue affected by a lifetime of low daily doses of fluoride? The sources of fluoride are numerous — from foods to toothpaste, drinking water and during dentist visits.

Health Canada reportedly will accept the panel’s recommendation to cut the level in water to 0.7 parts per million from the current guideline range of 0.8 ppm to one ppm.

Calgary’s level has already been reduced to 0.7 ppm, with room to go lower. Toronto cut its allowable level in 2005 to 0.6 ppm, a level its public-health department says is supported by “credible scientific evidence.”

Fluoride should be used in moderation. Its harm may be disputed, but common sense dictates one should never rely too heavily on chemicals, at any time. They’re no replacement for good habits. Council should brush up on the issue, review the science and weigh the benefits against the risks. Water is the very stuff of life — essential to all living things on the planet. There is nothing more important for council to revisit.

© The Calgary Herald 2008