FDA Proposes New Standard on Fluoride for Bottled Water

(CNN) – The US Food and Drug Administration is proposing a lower fluoride concentration standard in bottled water, but some scientists and environmental groups believe the proposed limit is still too high and is a danger human health.

If finalized, the new regulation would lower the allowable levels of fluoride in domestic bottled water bottles imported to 0.7 milligrams per liter, a slight reduction from the current standard of 0.8 milligrams per liter authorized by the FDA.

The proposed standard would apply only to bottled water with the addition of fluoride. This would not affect allowable levels of fluoride in bottled water that may contain fluoride from source water.

Dental health

The rule proposed by the FDA complies with a 2015 recommendation by the US Public Health Service, part of the US Department of Health and Human Services, that suggests that 0.7 mg per liter is the optimal fluoride concentration for community water systems that add fluoride.

The new rule "is based on the results of evolving research on optimal fluoride concentrations that balances the benefits of fluoride in preventing tooth decay with its risk of causing dental fluorosis, a condition most often characterized by plaques white teeth, "said the FDA in its statement. . Dental fluorosis is caused by the excessive absorption of fluoride over a long period, when adult teeth form under the gums.

But the concerns of some scientists go far beyond fluorosis.

"Since fluoride can damage brain development, I would recommend keeping the maximum concentration of fluoride in bottled water at a level below 0.7 mg / L," said Philippe Grandjean, badistant professor in Environmental Health at Harvard TH Chan School. of public health, wrote in an email.

Christopher Neurath, research director of the American Environmental Health Studies Project, who is connected to the Flouride Action Network, an environmental advocacy group, said "that there are currently scientific studies showing a rapid increase in the neurotoxicity of fluoride ", with research showing a direct link between children's IQ and their level of fluoride exposure in the uterus:" This is our biggest concern. "

Effects on behavioral and cognitive health

Morteza Bashash, an badistant professor at the Dalla Lana School of Public Health at the University of Toronto, discovered that higher fluoride levels, measured in urine samples of pregnant women, were badociated lower IQ and increased risk of ADHD in Mexican children.

Bashash in particular found a drop in children's intelligence test scores for each 0.5 milligram per liter increase in fluoride exposure above 0.8 milligram per liter detected in urine. from a pregnant mother. It's unclear whether there is research applicable to the American population, he told CNN.

In Mexico, for example, the government provides fluoride reducing caries by adding salt, not water (many people avoid drinking tap water).

Nevertheless, the results of his research were "based on the actual measurement of fluoride absorbed into the body". And a Canadian study (link) Presented at a conference last year and studies conducted in China have shown that IQ losses were related to fluoride levels in a similar order of magnitude.

Because of similar fluoride sources, regulations, and diets, the results of urine tests in Canada are probably similar to US urine levels, Bashash said.

Neurath believes that the results of the Mexican and Canadian studies would generally apply in the United States because "urine fluoride is the best measure of total fluoride intake."

Canadian data for the last 15 years have shown that women living in cities with fluoridated water had urine fluoride levels "almost twice as high" as women living in non-fluoridated cities. "The consumption of fluoride from drinking water is the main source of fluoride for these women," he said.

The effects of prenatal fluoride exposure on IQ are "very important," says Neurath. "And based on the population, it is very worrying."

The proposed rule may not be adequate

Neurath itself has published this year a study on dental fluorosis, based on data from the National Health and Nutrition Survey, which revealed a "dramatic increase in fluorosis" compared to the results of 39, ten years ago. (The study, although published in a peer-reviewed journal, was co-authored by a lawyer representing the Fluoride Action Network in a lawsuit regarding the regulation of fluoridation chemicals by US Environmental Protection Agency.)

More than 30% of adolescents in the study had moderate to severe dental fluorosis (35% of children had less severe signs), a "significant increase" compared to a survey conducted about a decade earlier, said Neurath. He thinks that it is unlikely that the proposed standard reduces dental fluorosis to acceptable levels.

However, he has a greater concern. "Dental fluorosis is a visible sign of overexposure to fluoride, but there are other non-visible signs and adverse health effects that are much more serious," said Neurath, based on the work of Bashash and Grandjean.

The work of Grandjean, which was funded by the National Institute of Environmental Health Sciences. "Our review of the studies conducted in China and our own field study are consistent with a recent study by US researchers in Mexico that high exposure to fluoride during pregnancy is badociated with toxicity to brain development.

"Since fluoride is added to the toothpaste to ensure that the tooth enamel surface is properly protected from cavities, it is not necessary to supplement the dietary fluoride intake," did he declare.

According to Bashash, fluoride in drinking water is considered one of the "greatest victories in public health" in caries prevention. While his job as a scientist is to study a given subject, it is up to decision-makers to develop a comprehensive understanding of what is needed. The FDA is studying "the big picture" by gathering evidence and evaluating the pros and cons according to national priorities. "It's been a hot topic for 60 years."

Linda Birnbaum, director of the National Institute of Environmental Health Sciences, explained that a "major inter-governmental working group" had reviewed available data from 2010 to 2011 and had concluded that the appropriate level of fluoride concentration in alcohol was 0.7 mg / L. water, which "balances protection against dental caries while limiting the risk of dental fluorosis".

The institute has funded studies that explore other health effects, she said, "and we are currently reviewing the information in a systematic review."

The International Bottled Water Association, a professional group, said it was in favor of the FDA's proposal to revise the quality standard for fluoride added to bottled water.

"Most companies are well below" the proposed new limit, according to Jill Culora, a spokeswoman for the badociation. "The proposed rule takes into account the many sources of fluoride in people's diets and will further reduce the risk of dental fluorosis, while providing an optimal level of fluoride to help prevent tooth decay."

Cavities are not the only concern, said Neurath: "The proposed rule is not adequate."