Fluoride: a double edged sword? Opinion by Giovanni Roverso


Fifty-seven percent of those responding to the advisory ballot choose to end fluoridation.  Forty-one percent would continue it. The city council will have final say however, with no promise of the survey making a difference. The city council will meet to discuss fluoridation in light of the results on Dec. 15. A final decision must be made by May 2016.

So, to fluoridate or not to fluoridate? There’s quite a bit of controversy and there seem to be possible risk factors in any case, depending on who you talk to. Here’s my take after researching the issue for just a few weeks, so add a pinch of salt, fluoridated salt if you see fit.

The debate is conducted on many levels including, fluoride effectiveness at preventing dental caries, fluoride safety, fluoride routes of action, and fluoride sources, to name a few; with special attention on the ethics of mass fluoridation, thoroughness of fluoride research and possible bias of the parties involved.

Why not fluoridate the water?

Fluoride can protect your teeth. Without going into how it does this with too much detail, I should mention that fluoride acts topically if applied on the surface (think toothpaste and dental floss) and systemically if ingested, for example. Ingesting it can also have a topical effect because the fluoride goes into your blood stream and then into your saliva.

It’s also important to keep in mind that it is widely acknowledged that the systemic effect seems to be mostly useful as permanent teeth are forming in children.

The main concerns are that there may be subtle negative results regarding the systemic effect over time, even at near-optimal doses which haven’t been thoroughly investigated yet.

I say near-optimal because it’s virtually impossible to control the dosage considering different people consume different amounts of fluoride. There are in fact countless sources beyond water.

Fluoride can be found in the air, food or soil. It can be found in many soft drinks like colas, in teas, and a variety fruit juices (probably because fluoride is a pesticide).

Furthermore, children could easily be over-exposed considering their size, people with kidney problems filter less fluoride out, people working in certain professions—for example, if you work with aluminum, magnesium, petrochemicals, in coal production, in a glass brick or tile factory—will have higher exposures to fluoride and/or other elements that could act together with fluoride synergistically to do more damage, some people are naturally hypersensitive to fluoride, and the list goes on.

Anti-fluoridationists overstate risks, pro-fluoridationists understate risks

Searching the web for fluoride safety information leaves one with more questions than answers, with a lingering smell of bias on either side of the debate.

Anti-fluoridation pages often have a knack of mixing in wild speculation and rumor with legitimate questions and research. The worst cases will say that it all started in Nazi Germany when fluoride was used to sterilize and pacify Jews and that the World Health Organization is the devil, works for the New World Order and wants to control your mind, so “hide ya wife and hide ya kids.”

While I would say some concern is reasonable, being paranoid to the extreme is not going to be taken seriously when abundant peer-reviewed research is available that disproves extreme claims. If fluoride is so bad for you for example, how is there no statistical difference in mortality rate between fluoridated and non-fluoridated communities?

Pro-fluoridation pages generally seem more well-groomed and refined than the opposition and assure viewers that it’s safe and effective with decades of research to back them up. Some big fish like the World Health Organization, the U.S. Centers for Disease Control and Prevention and the American Dental Association identify with this position. It’s clear though, they have taken a side; they want to save your children’s teeth and really prefer you don’t think about any under-explored research avenues too much.

Don’t worry about it

“While opponents of fluoridation have questioned its safety and effectiveness, none of their charges has ever been substantiated by generally accepted science,” the ADA has stated, “with the advent of the Information Age, a new type of ‘pseudo-scientific literature’ has developed. The public often sees scientific and technical information quoted in the press, printed in a letter to the editor or distributed via an Internet Web page. Often the public accepts such information as true simply because it is in print. Yet the information is not always based on research conducted according to the scientific method, and the conclusions drawn from research are not always scientifically justifiable. In the case of water fluoridation, an abundance of misinformation has been circulated. Therefore, scientific information from all print and electronic sources must be critically reviewed before conclusions can be drawn.”

Fair enough, after all “a lie can travel halfway around the world while the truth is putting on its shoes,” as the saying goes. Still though, some claims are based on promising preliminary research which deserves to be fleshed out for certainty’s sake.

The CDC does not seem to have any more doubts though: “The safety and effectiveness of fluoride at levels used in community water fluoridation have been thoroughly reviewed by multinational scientific and public health organizations (U.S., Canada, Australia, New Zealand, Great Britain, and by the World Health Organization) using evidence-based reviews and expert panels.

The safety and effectiveness of community water fluoridation continues to be supported by scientific evidence produced by independent scientists and summarized by panels of experts. The independent, non-governmental Community Preventive Services Task Force has noted that the research evidence does not demonstrate that community water fluoridation results in any unwanted health effects other than dental fluorosis, a condition that causes primarily cosmetic changes in the appearance of tooth enamel.”


Some high profile scientists, doctors and dentists believe potential risks are not being taken seriously enough, and that research that goes against the grain is discouraged.

“Fluoridation presents unacceptable risks to public health, and the government cannot prove its claims of safety,” former EPA senior scientist Robert J. Carton, PhD, has said, “EPA has attempted to silence scientists who do not follow the party line.”

Carton has also claimed that: “in April 1985, a person writing standards for EPA actually told me, in private, that he was lying. He said he was told to lie, and that he had to do what he had to do to keep his job.”

His statements, however biased they may be, are at least a little worrying if at all true.

Philippe Granjean, M.D., who is widely accused of overemphasizing fluoride risks, stated in 1985: “fluoride toxicity has been a ‘faux pas’ for many years, and anybody discussing this topic would be suspected to belong to the antifluoridation movement. Thus, the recently published Environmental Health Criteria 36 on Fluorine and Fluorides (WHO, 1989) only superficially discusses chronic toxicity, while beneficial effects and safety margins are dealt with in detail. As Temporary Adviser I was present at most of the Task Group meeting when the document was finalized. In accordance with the official fluoridation policy, information which could cast any doubt on the advantage of fluoride supplements was left out by the Task Group.”

Could it really be that large agencies are suppressing or discouraging research in order to keep fluoridation greenlit? It’s difficult to tell for sure since reality can be convoluted, but it’s definitely not an idea that should be completely thrown out of the window, however crazy that that may sound. After all, money interests and reputations can be touchy and socio-political pressure can be exerted to protect them.

The curious Mullenix case

That of Dr. Phyllis Mullenix, is an interesting and controversial case. She worked in the eighties and nineties at Forsythe Dental Center, in Boston, as toxicology department head under supervision of fluoride toxicology expert Harold Hodge and Forsythe Director Jack Hein. Her job was to head up this department to look at the environmental impact and the toxicity of products that are used by dentists and the dental community.

Hodge had been chief of fluoride toxicology studies for the University of Rochester division of the Manhattan Project in the forties and one of the founders of the Society of Toxicology. He had a defining influence on the adoption of fluoride in the U.S. as a caries preventative. Hein, who encouraged Mullenix to do toxicology research on fluoride had previously been a student of Hodge’s.

After Hodge’s death in 1990 and Hein’s retirement in 1991, Mullenix got a paper on fluoride submitted for peer review in 1994, and which got published in 1995. The paper was supposed to garner the interest necessary to get funding for more in-depth research.

The paper indicated that high-dose fluoride in the diet of rats could cause accumulation in parts of the brain when administered in over time, hyperactivity disorder when administered to the mother prenatally, and hypoactivity disorder when administered postnatally.

Her research got a surprising amount of attention, yet was denied further funding and was she was fired from Forsythe before her paper even got published. Mullenix said the reasons given for her firing was that she “didn’t get enough funds to do my research, number one; number two, the projects I worked on were not ‘dentally related.’ They also [said] that they weren’t interested in that kind of science, to look into the safety of fluoride. They didn’t consider that, well, as they put it, that’s not ‘their idea of science.’”

Several videos of Mullenix can be found on YouTube, and an extensive interview with her and the founder of the anti-fluoridation Fluoride Action Network can be found on that site, for what it’s worth.


Recent research committees such as the U.S. National Academies of Science Research Committee (NRC 2006) and the E.U. Scientific Committee on Health and Environmental Risks (SCHER 2010), were tasked on shedding more light on common questions regarding fluoridation. The panels indicated that that the quality and quantity of studies and data available is lacking for there to be a very high degree of certainty regarding safety of systemic fluoridation and dental fluorosis in a variety of cases.

I must premise that in 2013 John Doull, MD, PhD, and Chair of the National Research Council stated: “I do not believe there is any valid, scientific reason for fearing adverse health conditions from the consumption of water fluoridated at the optimal level”

Nonetheless the NRC’s 2006 report indicates that more research needs to be done on fluoride concentrations in human bone especially in the post-menopausal women and the elderly, and in soft tissues (e.g., brain, thyroid, kidney) following chronic exposure. The report also found research on aluminofluoride complexes to be lacking and deserving of more attention.

The following are some of the most interesting recommendations the NRC made in their report (complete text available for free online):

  • More studies are needed on fluoride concentrations in soft tissues (e.g., brain, thyroid, kidney) following chronic exposure.

More research is needed on bone concentrations of fluoride, especially in people with altered renal function, as well as other potentially sensitive populations (e.g., the elderly, postmenopausal women, people with altered acid-balance), to better understand the risks of musculoskeletal effects in these populations.

  • The biological effects of aluminofluoride complexes should be researched further, including the conditions (exposure conditions and physiological conditions) under which the complexes can be expected to occur and to have biological effects.

  • The possibility has been raised by the studies conducted in China that fluoride can lower intellectual abilities. Thus, studies of populations exposed to different concentrations of fluoride in drinking water should include measurements of reasoning ability, problem solving, IQ, and short-and long-term memory. Care should be taken to ensure that proper testing methods are used, that all sources of exposure to fluoride are assessed, and that comparison populations have similar cultures and socioeconomic status.

  • Studies of populations exposed to different concentrations of fluoride should be undertaken to evaluate neurochemical changes that may be associated with dementia. Consideration should be given to assessing effects from chronic exposure, effects that might be delayed or occur late-in-life, and individual susceptibility

  • Further effort is necessary to characterize the direct and indirect mechanisms of fluoride’s action on the endocrine system and the factors that determine the response, if any, in a given individual. [The endocrine system is comprised of all the major hormone producing glands in the body, including the thyroid and the pineal gland.]

Better characterization of exposure to fluoride is needed in epidemiology studies investigating potential endocrine effects of fluoride. Important exposure aspects of such studies would include the following:

    • collecting data on general dietary status and dietary factors that could influence the response, such as calcium, iodine, selenium, and aluminum intakes

    • characterizing and grouping individuals by estimated (total) exposure, rather than by source of exposure, location of residence, fluoride concentration in drinking water, or other surrogates

    • reporting intakes or exposures with and without normalization for body weight (e.g., mg/day and mg/kg/day), to reduce some of the uncertainty associated with comparisons of separate studies

    • addressing uncertainties associated with exposure and response, including uncertainties in measurements of fluoride concentrations in bodily fluids and tissues and uncertainties in responses (e.g., hormone concentrations)

    • reporting data in terms of individual correlations between intake and effect, differences in subgroups, and differences in percentages of individuals showing an effect and not just differences in group or population means.

The effects of fluoride on various aspects of endocrine function should be examined further, particularly with respect to a possible role in the development of several diseases or mental states in the United States. Major areas for investigation include the following:

    • thyroid disease (especially in light of decreasing iodine intake by the U.S. population);

    • nutritional (calcium deficiency) rickets;

    • calcium metabolism (including measurements of both calcitonin and PTH);

    • pineal function (including, but not limited to, melatonin production); and

    • development of glucose intolerance and diabetes.

SCHER also said:

Exposure assessment is the critical requirement here. Improving the assessment needs:
1) New biomarkers for long-term fluoride exposure.
2) Standardized methods for exposure assessment that add together all routes of exposure.
3) Better information on fluoride in food and bioavailability of fluoride.
4) Epidemiological studies, taking advantage of the existing mother-child cohorts to investigate the role of fluoride intake in dental fluorosis and dental health.”

Clearly there is a lot of research to cover, all of which would be impossible in this commentary, so I’ll stick to a couple main research topics over the next two sections.

Fluorosis is primarily cosmetic?

Let’s think about fluorosis, the supposed only negative effect of low-dose fluoride.

Dental fluorosis is due to an excessive systemic exposure to fluoride during tooth development (between birth and eight years of age), with white discoloration in milder forms and brown stains and pitting in the worst cases.

A 2010 study found that fluorosis rates have nearly doubled since the eighties in the U.S.; in fact 40.7% of adolescents aged 12-15 were found to have dental fluorosis between 1999 and 2004. Only a very small portion of cases were moderate or severe though, which is good news considering that severe cases can actually mean teeth can chip more and get cavities more easily. Such cases are usually due to accidental overdoses

Still, could mild dental fluorosis also indicate mild skeletal fluorosis, and might it be dangerous at some point? The WHO also has stated that fluoride accumulates in the bone progressively over many years.

Bones with even moderate fluorosis have been found to be more prone to breakage than average, among other issues.

In 1970 the WHO said: “At higher levels of ingestion – from 2 to 8 [milligrams] daily, skeletal fluorosis may arise … Whereas dental fluorosis is easily recognized, the skeletal involvement is not clinically obvious until the advanced stage of crippling fluorosis … early cases may be misdiagnosed as rheumatoid or osteo arthritis.” Is that concerning?

At the current level of fluoridation in Port Angeles, water is kept at concentrations between .8 and .96 mg per liter or parts per million (ppm). That means that according to the 1970 WHO data, if you drink just two and a half liters a day you are in the skeletal fluorosis risk-zone, and that’s without considering any other sources of fluoride.

Recent statements from the WHO have played its earlier findings down, stating fluorosis occurs only at acute high-level fluoride exposures. As quoted by an NRC updated in 2007, the American Dietetic Association went one step further in 2005, stating that low-dose fluoride is essential for preserving bone mineralization.

While I couldn’t verify the statement in the source provided, a 2000 study by Phipps et al. sampling almost 1000 individuals concluded, “This is the first prospective study with adequate power to examine the risk of specific fractures associated with fluoride on an individual rather than a community basis. Our results show that long term exposure to fluoridation [at 1 ppm] may reduce the risk of fractures of the hip and vertebrae in older white women. Because the burden of osteoporosis is largely due to fractures of the hip, this finding may have enormous importance for public health.”

That’s definitely comforting, yet my inner consumer would still like to see more research at low doses, especially so as to determine the threshold between enough and too much.

Synergy: can fluoride cause harm when combined with other elements like aluminum?

In the past few decades, some research has been done indicating that molecules containing fluoride and certain other elements, especially aluminum and barium, could have a synergistic effect. Such an effect occurs when the combined action is greater than the sum of each element acting separately.

The most interesting interaction seems to be that of fluoride and aluminum.

According to a 1988 paper by Martin, et. al., of the more than 60 metals on the periodic chart, Al3+ binds with fluoride most strongly.

Research has shown that aluminum can have a role in the formation of amyloid plaques in the brain which are the cause of Alzheimer’s dementia.

A 2009 study on rats by Tanzeer, et. al., showed that when rats are given fluoride in combination with aluminum, it produces toxic results on the rat brain at high concentrations over time. In this experiment it was shown that aluminum can cross the blood-brain barrier more easily thanks to fluorine.

The effect of fluoride could mean a lot for people are exposed to aluminum to a high degree.

A 1998 study on rats by Varner, et. al., showed that in rats accidentally fed a large quantity of aluminum, those given water with low amounts of sodium fluoride suffered significant damage, resulting in kidney disease, dementia, and an elevated mortality rate compared to non-fluoridated controls (40% compared to 10% mortality rate).

Mullenix has pointed out that the scientific community’s understanding of chemical signaling in cells is thanks to the use of aluminum fluoride complexes which were used to alter important cell functions.

Are people really exposed to significant amounts of fluoride and aluminum though?

“Besides vaccines, aluminum is found in a number of baked goods, processed cheeses, and teas. In one study, food was found to supply 25 times more aluminum systemically than public drinking water. Recent studies have shown very high levels in a number of commonly used feeding and intravenous parenteral solutions used in pediatrics,” according to a 2009 peer-reviewed paper by Blaylock, et. Al, “aluminum not only accumulates in the brain but produces inflammation, generates free radicals, and interferes with neuronal tubular function.”

“Sources of human exposure to aluminum include drinking water, tea, food residues, infant formula, aluminum-containing antacids or medications, deodorants, cosmetics, and glassware,” a 2002 Strunecka and Patocka study also reports, according to NRC 2006.

According to Greger JL of the Department of Nutritional Sciences, University of Wisconsin, “most adults consume 1-10 mg aluminum daily from natural sources. Intake of aluminum from food additives varies greatly (0 to 95 mg Al daily) among residents in North America, with the median intake for adults being about 24 mg daily. Generally, the intake of aluminium from foods is less than 1% of that consumed by individuals using aluminium-containing pharmaceuticals.”

Aluminum can also be found in water.

“Aluminum in drinking water comes both from the alum used as a flocculant or coagulant in water treatment and from leaching of aluminum into natural water by acid rain” (Agency for Toxic Substances and Disease Registry 1999; Li 2003).

Concerningly, a 1985 study by Pitter, et. al., found that drinking water contains a substantial fraction of fluoro-aluminum complexes rather than free fluoride.

An interesting result of the Tanzeer study was that, “fluoride and aluminum have a strong tendency to form a complex, and even if their ingestion is from different sources, they have a tendency to form the complex in vivo.” The ATSDR 1999 findings also indicated alumino-fluorides “can occur when a person ingests both a fluoride source (e.g., fluoride in drinking water) and an aluminum source.”

“As well, with the increasing prevalence of acid rain, metal ions such as aluminum become more soluble and enter our day-to-day environment; the opportunity for bioactive forms of aluminum fluoride to exist has increased in the past 100 years” (Li 2003; Shu et al. 2003; Wong et al. 2003).

It is clear that more research needs to be undertaken.


When I started looking into fluoride research I had doubts. Now, after relatively just scratching the surface, while I have some significant reassurances, I still have way too many doubts.

I’m glad fluoride keeps teeth from decaying, but do we really need more than that which we already get besides water?

I grew up in Italy where no fluoride is added to water (though it does have some in it naturally). Dentists there claim there’s enough from other sources and hey, for what it’s worth, I don’t have any cavities. All I did was brush once a day before bed, floss sometimes and get regular cleanings. Oh, and I love iced tea. Why risk an increase of potential risks?

Also, if caries are such a problem with kids, maybe we should bump up free dental cleaning for affordable care act users to twice a year, for example. There could also be better dental education, with schools involving parents, for example. Poor nutrition also plays a role in dental decay, as well as in fluorosis. Maybe schools should better teach children and their parents about the difference a healthy diet can make long-term.

Plus, if fluoride is so safe, why aren’t we seeing more in-depth studies where they’re needed to ease doubters’ worries? Why are there still so many questions after 70+ years of research? Organizations can give assurances all they want, but an exhaustive range of data is what’s needed for true consumer confidence.

The majority of Port Angeles city water users want to play it safe. Is too safe? Or would it even be ethical to continue medicating against the will of the majority?

Originally printed in the Buccaneer


  1. Nadia Seymour

    Dear Giovanni Roverso,

    Nice to see someone take the time to look into an issue with such balanced thoroughness. Refreshing!

    I would venture to reiterate what has been said so often before: Those that wish to use fluoride are free to do so, easily. There is no need to indiscriminately and irreversibly distribute fluoride in the public’s water supply, where individual choice is removed.

    The pros and cons of fluoride are really not what this controversy is about. It is about choice, much like labeling what is in your food.

    You may or may not believe in gluten intolerance. Is it a fad diet, or really a medical issue? Opinions vary, but you get to choose, privately, because foods have labels on them. Peanut allergies? You get to choose, because foods have labels.

    But there is no choice, nor labels with Port Angeles’ current water policies. You, visitors, pets, house plants, and lawns all get fluoride. There is no dose measurement, nor accountability.

    So, global conspiracy or the best public policy since they sprayed the countryside with DDT to control mosquitoes, everyone has an opinion that should be respected. You might not agree, but you don’t have to.

    To allow the public’s water to be free of this chemical additive only allows those that don’t want fluoride to have the water they pay for. Like you. If you believe in fluoride, just buy a tube of tooth paste. Everyone gets what they want. So simple.

    It is about choice.

    1. Giovanni Roverso


  2. Michael Gentry

    Thank you Giovanni. This is a great recap of all the information flying around about this controversy. It helps narrow down the important issues. I agree with your final take on it.


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