An expert panel Health Canada commissioned to study the risks of fluoride exposure says the government should cut the recommended amount in drinking water, encourage the use of low-fluoride toothpaste by children and have makers of infant formula reduce levels in their products.
The proposals were made in a report submitted to the federal government in January of 2007, but made public last month with little fanfare when Health Canada posted a summary on its website.
Fluoride is such a staunch cavity-fighter that it has been routinely added to toothpaste and municipal water supplies for decades. Traces are also found in infant formula.
But it has recently emerged as a controversial chemical for some public-health advocates because of contested research linking it to intelligence-quotient deficits in children; osteosarcoma, a rare type of bone cancer in young boys – which felled Canadian icon Terry Fox – and the mottling of youngsters’ teeth, a condition known as fluorosis.
Although the panel concluded the “weight of evidence” supports neither an association between fluoride and cancer, nor the findings of IQ deficits, its three recommendations would lead to reduced exposure if implemented, particularly for children.
The panel recommended reduced fluoride exposure because it was worried children might be getting too much of the chemical from diet, water and toothpaste, placing them at increased risk of fluorosis, said Steven Levy, a panel member and a research professor at the University of Iowa’s College of Dentistry.
The call for children’s low-fluoride toothpaste, which is common in Europe, was made because of concerns that youngsters might inadvertently swallow the substance while brushing. The panel said lightly fluoridated toothpaste is “already available in other countries” and Health Canada should “promote and encourage” its use.
In Canada, children’s toothpaste, which sometimes is candy-flavoured, has about the same amount of fluoride as adult toothpaste. But some varieties, sold mainly at health-food stores, do not contain any of the chemical and are labelled “fluoride free.”
In a response to questions from The Globe and Mail, Health Canada said in an e-mail that it will accept the panel’s recommendation to cut the fluroide level in drinking water to 0.7 parts per million from the current guideline allowing a range of 0.8 ppm to 1 ppm.
Fluoride is added to the municipal water supplies of about 13.5 million Canadians, or about 43 per cent of the population. But the practice varies widely by province, with almost no fluoridation in Quebec and British Columbia and about 70 per cent of people receiving treated water in both Ontario and Manitoba.
The impact of Health Canada’s change may be muted because some jurisdictions are already ignoring the department’s water-fluoridation guideline and are applying even more stringent limits.
Toronto, for instance, cut allowable levels in 2005 to 0.6 ppm. A report issued by its public-health department last year says “credible scientific evidence” supports the lower figure.
But the adoption of a new federal guideline will mark the continuation of a long-running reduction of fluoride in water supplies. When fluoridation began in the 1960s, it was customary for water to contain as much as 1.2 ppm.
In its response to The Globe, Health Canada said it is not concerned that millions of Canadians have been exposed for several decades to levels much higher than the new guideline will call for because the current maximum acceptable concentration in water supplies is 1.5 ppm.
The panel’s summary does not specify an optimum fluoride concentration for children’s toothpaste, although some types available in Europe contain a quarter to a half of the amount, ranging from 1,000 ppm to 1,500 ppm, common in North American products.
Because toothpaste is spit out after use, it is allowed to contain far higher fluoride concentrations than drinking water, which is ingested.
Dr. Levy said “it would be good” to have toothpaste available in North America for children up to age 4 that would contain about half the fluoride of regular toothpaste.
Health Canada said it is aware that youngsters might swallow toothpaste and, as a safeguard, already recommends that those under 6 be supervised when brushing and be given only pea-sized amounts on their brushes. The department also said parents should contact a poison-control centre or other medical help “right away” if more toothpaste than is used for brushing is swallowed.
Infant formula contains traces of fluoride, because of the small amounts naturally contained in its ingredients, according to two manufacturers, Mead Johnson Nutritionals and Nestlé Canada Inc., which said their ready-to-use products contain less than 0.3 ppm.
There are currently no industry or regulatory standards for fluoride in baby formula.
Health Canada said cutting the recommended amount in municipal drinking water to the 0.7-ppm level “will help address this concern” over “the risk of excessive fluoride exposure from formula.” It said adverse effects would occur only after “extended periods of exposure” in infants consuming large quantities of reconstituted formula.