I think we can all agree that “Look, Mom—no cavities!” is good news. But we continue to disagree about the best way to achieve that. Fluoridation of public water sources remains controversial as a public health measure despite the strong evidence that fluoride prevents tooth decay. Public debates can become quite heated, with one side praising water fluoridation as an essential preventive and the other side demonizing it as coerced ingestion of a poison. Recently fluoridation has faced new accusations that it lowers IQ. Which side is right? Let’s see how the evidence and the arguments on each side hold up to scrutiny.
Optimal Level of Fluoride in Drinking Water
The natural fluoride content of drinking water varies widely by geographic location. Studies have shown that people whose water is low in fluoride are more likely to develop cavities. If the fluoride content is too high, they can develop fluorosis, with tooth discoloration and other problems. The EPA has set maximum levels of fluoride at 2 ppm to prevent enamel fluorosis and 4 ppm to prevent skeletal fluorosis. The World Health Organization has set the recommended maximum level at 1.5 ppm.
In 2015, the U.S. Department of Health and Human Services updated the optimal fluoride level in drinking water to 0.7 mg of fluoride per liter of water (equivalent to 0.7 parts per million or ppm). This was based on extensive research and consideration of other sources of fluoride. If the natural fluoride content of drinking water is lower than 0.7 ppm, water fluoridation can raise it to 0.7. If it is over the recommended maximum level, there are ways to lower it. Estonia had levels as high as 7 ppm (10 times the optimum), and they were able to successfully lower the fluoride exposure of their citizens by using reverse osmosis technology and drilling new wells. Fluorosis should not occur at currently recommended levels of water fluoridation.
Fluoride Reduces Cavities
Fluoride is the key to preventing and controlling tooth decay. A clear scientific consensus: the evidence shows fluoride is effective, both at the individual and at the community level. Individual measures include taking fluoride supplements and getting various professional fluoride treatments by dentists. Community measures include water fluoridation, educational programs, and fortification of foods such as table salt. Few people would deny that fluoride is effective; the disagreements are about how fluoride should be supplied.
Water Fluoridation is Safe and Effective
Over a hundred studies in various countries have shown consistent results. Early studies showed that water fluoridation cut the risk of tooth decay by around 50%. Current estimates are lower, because today’s public is exposed to many more sources of fluoride, like fluoride toothpaste. Recent studies have confirmed the benefit. For instance, a 2018 study in Australia found consistent associations between low lifetime exposure to fluoridated water and childhood caries (tooth decay). The current estimate by the American Dental Association is that it reduces tooth decay by at least 25% in both children and adults.
From the American Dental Association (ADA) to the World Health Organization (WHO), around a hundred national and international professional medical societies, research organizations, and health agencies around the world have endorsed water fluoridation as safe and effective. International scientific reviews show no link between any adverse health effects and drinking water with fluoride levels that do not exceed 1.5 ppm. After evaluating the evidence, the CDC dismissed claims that fluoride increased the risk of cancer, Down syndrome, heart disease, osteoporosis, bone fracture, AIDS, low intelligence, Alzheimer’s disease, allergic reactions, and other health conditions. And there is no evidence that water fluoridation has ever harmed the environment.
Fluoridation is the most cost-effective way to prevent tooth decay. Every $1 invested in fluoridation saves $38 in treating dental problems.
Alternatives to Fluoridation
In some areas fluoridation is not feasible, for cost or logistical reasons. It is banned in China where naturally high fluoride levels in water are a serious problem. In 2010, 66% of U.S. residents had access to fluoridated water, compared to 70% in Australia and 70.5% in Chile. When some countries that had previously practiced fluoridation discontinued it, they saw a rise in tooth decay. Currently only about 5.7% of the world’s population, in only 24 countries, get added fluoride in their water. The rest of the world has chosen other methods of reducing tooth decay, such as topical application, fluoride toothpaste, and adding fluoride to milk or table salt. These methods are also effective.
Opposition to Water Fluoridation is not Based on Science
The opposition to water fluoridation is not based on any credible scientific evidence that properly regulated fluoridation causes harm, but on philosophical and ethical concerns that value individual rights over the common good. It is seen as mass medication without individual consent. Legal challenges in the courts have mostly been unavailing.
Conspiracy theories have been invoked as well, most memorably as parodied in the movie Dr. Strangelove, where General Jack D. Ripper orders a nuclear strike against the Soviet Union to counteract what he imagines is a nefarious Communist plot to fluoridate our water:
A foreign substance is introduced into our precious bodily fluids without the knowledge of the individual, and certainly without any choice. That’s the way your hard-core Commie works.
The communists were not the only ones blamed; it has also been called a capitalist ploy and a way for the aluminum industry to dispose of toxic fluoride wastes and make a profit.
It seems to me the opposition to fluoridation often originates as a poorly informed knee-jerk emotional reaction. (Ain’t no dang gummint gonna make me put nasty chemicals in my body!) Once people feel uncomfortable about fluoridation, it is a simple matter to cherry-pick the scientific literature and find rationalizations to reject it. And there is a small minority of dissenting scientists who find reasons to reject the scientific consensus. You can find a Ph.D. to support any belief.
The Fluoride Action Network has a list of “50 reasons to oppose fluoridation.” I find them far from persuasive.
- “Fluoride is the only chemical added to water for the purpose of medical treatment.” (It’s not for treatment, but for prevention. Being the only one would not be a reason to reject something: it might be the only one where adding it is indicated. There is precedent: we add iodine to table salt to prevent goiter.)
- It’s unethical because they don’t get informed consent from individuals. (They don’t get informed consent from every user of iodized table salt, either. And others have argued that it is unethical to deny this public health benefit to our children.)
- The dose can’t be controlled. (Here they have a good point. Some people drink large amounts of water; others avoid water or replace tap water with bottled water that may not contain fluoride. People get fluoride from other sources like toothpaste, supplements, and dental treatments. Similarly, we can’t control the dose of iodine, since some people use non-iodized salt. No one considers that a problem; certainly not a reason to stop adding iodine to salt.)
- Fluoride is not an essential nutrient. (That’s beside the point.)
- Fluoride accumulates in the body. (But there’s no evidence that water fluoridation leads to accumulations of fluoride that cause health consequences.)
- Countries that don’t fluoridate their water have seen similar declines in dental decay. (That’s because they provide fluoride in other ways, like adding it to table salt.)
- Fluoride causes arthritic symptoms. (No, it causes skeletal fluorosis, but only in much higher doses than people get from water fluoridation.)
That’s enough of a sample to give you an idea of the quality of their arguments. They’re mostly speculation, misdirection, animal studies, and logical fallacies.
Does Water Fluoridation Decrease IQ?
The Fluoride Action Network claims that 33 studies have shown an association between fluoride exposure and reduced IQ. These studies, mostly out of China, did not address water fluoridation at all. They compared areas with very high levels of fluoride in natural water sources to areas with lower levels. The levels associated with lower IQ were far higher than the amounts in fluoridated water. Their low-fluoride group got a similar amount to what is in fluoridated water.
Even Snopes has debunked this claim: “the claim that there are scientific studies that support the notion that water fluoridation can cause developmental problems in children that result in lower IQs is false.”
Which is Unfair—Fluoridating or Not Fluoridating?
Very few of the arguments against water fluoridation hold up to scrutiny, but some do. If you are an elderly person with dentures, you can argue that fluoridation will not benefit you personally and that it is an arbitrary, unfair government imposition. It will only cost you tax dollars you did not choose to spend, and you didn’t give informed consent. You can argue that we can’t be 100% certain it won’t cause harm.
This article appeared in Skeptic magazine 24.4
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What to Do?
The CDC considers water fluoridation “one of the 10 great public health achievements of the 20th century.” Dentists recommend it (even though conspiracy theorists sometimes claim that doctors and dentists want to keep us sick in order to increase their business!). If you reject it, aren’t you obligated to find another way of protecting poor children? 
About the Author
Dr. Harriet Hall, MD, the SkepDoc, is a retired family physician and Air Force Colonel living in Puyallup, WA. She writes about alternative medicine, pseudoscience, quackery, and critical thinking. She is a contributing editor to both Skeptic and Skeptical Inquirer, an advisor to the Quackwatch website, and an editor of sciencebasedmedicine.org, where she writes an article every Tuesday. She is author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon. Her website is SkepDoc.info.
This article was published on January 14, 2020.
I usually love Dr Hall’s articles, but her section, “Optimal Level of Fluoride in Drinking Water”, blew that away: 2 ppm – 4 ppm, then 1.5 ppm, finally 0.7 ppm. How much closer to zero will the experts go? She’s not exactly inspiring my confidence in the science here.
This is a weak argument for forced fluoridation of water. It is oversimplified the near communistic.
The money spent by municipalities to fluoridate the water could be equally spent on program where the citizenry could voluntarily opt-in for topical application of fluoride.
What is the difference between raw fluoride coming from aluminum processing and clinical grade fluoride? Does fluoride recombine with aluminum ingested Say by using aluminum foil or aluminum cookware in food processing? What happens to the human body particularly the brain if they do recombine?
Personal freedom seems to be a huge issue among those concerned with fluoridating the water. So, I ask the anti-fluoride activists: how much of your personal freedom to do whatever you want with your time are you surrendering to the helping the leaders of the anti-fluoride movement with their agenda when, most likely, the outcome for you personally is totally inconsequential?
Not an impressive article. A bit more homework is in order for the reviewers over at skeptic.
https://www.physiciansweekly.com/fluoride-exposure-tied-to-kidney-liver-function-changes-in-youth/
There are MANY studies questioning the health effects of ingested fluoride and I’m not going to spend my time doing what Skeptic should be doing before printing such material. People drink differing amounts. Physiologically we are all unique with different capacities to clear substances and some with vulnerabilities for particular substances to accumulate.
The level of arrogance in this writing is impressive but the fact that skeptic is willing to publish it is sad. Do a simple clinical trials or Google search on fluoride ingestion and health effects. I simply do not care if it prevents cavities if it has neurological and other organ system effects. This is all without mentioning that topical use is available and in all toothpastes.
This all even goes without speaking to the larger issue at hand. Our personal freedoms. My not wishing to ingest fluoride but rather apply it topically puts ZERO other people at risk. If I have to pay for one additional cavity filling, I’ll pay for it. Quit giving away our freedom for the sake of your feelings of wanting to appear scientific. This comes from a medical provider.
– a very skeptical reader
Jim incorrectly characterizes my comment on the matter of military service as, in his words a matter of who has a ‘right’ to comment. I never used that word. He falsely puts words in my keyboard then refers to my alleged comment as ‘stupidest’. You may be appalled by my lack of respect for the military, but I did not say she does not have right to speak and have an opinion. Her opinion is for me, diminished by her previous life choices. I listed behaviors by the military that are at matter of life and death and historical and verifiable.
In Australia the best that the dental research suggests if that fluoridation of water is responsible for 10-20% reduction in decay in teeth of children. Very little in relation to adults. That research also shows that 40% of children in non-fluoridated low mineralised waters also do not have any caries. My hypothesis is that parental education and supervision og oral hygiene of children and good nutrition is the crucial relationship with eradicating dental caries entirely. The dental associations have no end game for fluoridation nor preventable oral health conditions.
The concept of public health intervention and the data used to recommend this one seem to be beyond many of the commenters here. There is a ton of data regarding fluoride levels in water all over the world and outcomes based on those levels, and whether the fluoride was added or came out of the ground dissolved in the water shouldn’t really matter. Data shows that bone and tooth health are best when flouride levels in the water are within a range, and no one here is presenting a reasonable argument that it makes a difference that the water has had the fluoride added or there naturally.
Public health practitioners use information like that to recommend chlorinated water to reduce coliform bacteria in drinking water, to recommend that Typhoid Mary not work in a restaurant, and that wells acting as sources of cholera have the handles removed. And they decide whether it is OK to sell penicillin or ibuprofen or Lipitor in the US, and whether there is a good reason to ban the sale of poison ivy in cream form. New data may arise and cause a change in the evaluation process, but we have over 100 years of data on fluoride in the water and outcomes like cancer, heart disease, kidney failure, or dental caries, and there is no evidence that levels between 0.5 and 1 PPM cause harms but do have benefits.
And if someone in the military has no right to speak about health, then the commander in chief, the president, or the surgeon general, of I suppose anyone who is a citizen of a country that dropped the atom bomb has no right to speak either. And if you have had a cavity or drank city water where fluoridation takes place, I suppose that also applies. The comment about the fact that someone who has been in the military has no right to comment is the stupidest comment I have ever read at this site, where typically discussions may be heated, but at least present a reasonable point of view.
The author is a US Air Force Colonel. Think about that. Over the decades since World War II….Carpet bombing South East Asia, napalm, agent orange, nuclear blackmail, drone warfare, the biggest consumer of fossil fuels, (oil), on the planet, cluster bombs, white phosphorous, death from the skies…these are the practices of the US military, weapons producers and the Industrial/ Congressional Complex. So, Skeptic would have me accept this persons opinion on health or anything? not so much.
Some fluoride opponents and some commenters here claim that the disadvantages of adding fluoride are not known. Natural fluroide levels vary greatly, giving a natural experiment. Authorities claim to have identified the optimal levels. Perhaps a very knowledgable person could argue with that judgment, but the author explained this very early in the piece.
Here’s a novel idea: don’t drink the water!
Dig your own well, bottle water, distilled water, whatever. And if you have doubts about vaccines, homeschool! GMOs? Grow a garden.
No need or to fret about the government- just watch out for those black helicopters.
Arguing that adding a substance to water (because it prevents one public health issue) – when it is unknown how much will be consumed and unknown what effects it has on other aspects of human health – is fundamentally flawed.
For example, there is significant evidence that fluoride detrimentally affects the thyroid. Thyroid disorder is rampant in the US (and other countries with fluoridation).
Fluoridation seemed like a good idea but at its core is an emotional argument about children without any INFORMED AND BALANCED assessment of fluoride on the human systems or on the overall public health outcomes.
As with many health policies, it does not consider the multi-dimensional aspects of human health.
Child’s in cities that put fluoride in water not even know what is a tooth carie.
Fluoride is so effective in prevent tooth decay, that today some people think that it’s not necessary anymore!!!
A few points to make here. First, let us affirm the obvious – that the cause of tooth decay is not lack of Fluoridation. The rates in Australia of babies and children having their earliest teeth removed long prematurely is causing dismay among Dentists, and that is despite the greater part of our country being long fluoridated. Better dental hygiene as well as better eating habits are emphasized whenever the issue is raised. The last occasions on which I saw alarming images of this on TV, there was not a single mention of the claimed benefits of Fluoridation.
Second. it is disquieting to note that excess or rejected quantities of the fluoridating material is absolutely forbidden to be dumped in any waterways, or in the ground or in rubbish. the only place this fundamentally toxic substance can be deposited is in our drinking water. Up until the introduction of Fluoridation round the world in the 60s, Fluoride was a toxic waste product; and it was a godsend for the makers of fertilizers when they discovered they could make a huge amount of money by a new way of use.
Third. I well recall, though I live in Australia, that for the first 50 years or so of Fluoridation in America, the proportion of the substance in the drinking water was described as absolutely safe and appropriate, and all scientific authorities agreed on that. Then all of a sudden just a few years ago, the powers that be declared the proportion was too much and reduced the dose in the drinking water.
Lastly, and to be a bit cynical about the process, it is rather obvious I think, that it would always be in the firm interests of the manufacturers who produce junk food, sugar, soda drinks etc, to promote a way out that does not involve reduction of the ingestion of their products.
I agree with Scepttor that more data would be helpful in regards to how much fluoridated water you’d have to drink for it to be unhealthy, including if you do or do not use fluoridated toothpaste. So if you drink a gallon a day of 1ppm fluoridated water, would that give you too much fluoride? What if you drank two gallons a day? Or would you not get enough if you only drank half a gallon a day? What would be optimal amounts for slight people versus heavy boned people? Is it only teeth that are helped with fluoride or does it help other bones as well?
Making a good human body is like baking a cake. Get the ingredients right . If is moral to take something OUT of water – like bugs – then it is moral to augment essential components. Simple.
It would have been nice to have a few extra sources or points of data here. For example, which countries are adding fluoride to milk or salt? How many, what other methods are they using, etc?
Which countries & where are the sources for this statement: “When some countries that had previously practiced fluoridation discontinued it, they saw a rise in tooth decay”.
For future reference, in a science-based article about a controversial topic, keeping things ambiguous (repeatedly saying “some countries”) and omitting sources for statistical statements isn’t going to help win any arguments.
It also would have been useful to address exactly how much tap water with x amount of fluoridation would be enough to potentially be a health threat for fluorosis. Yes ppm was discussed but that is also ambiguous jargon. Drinking how many liters per day / month / year of 2ppm fluoridated water is going to put me at risk for fluorosis? 4 liters a day? How about 4 liters a day of 1ppm fluoridation, how much is going to accumulate and how close am I to being in danger? Why exactly have those ppm numbers been implemented? Is drinking one glass a day of 7ppm fluoridation dangerous? Missed opportunity to talk about how fluoride actually accumulates and how quickly.
The author says “there’s no evidence that water fluoridation leads to accumulations of fluoride that cause health consequences”. But obviously some amount of accumulation does lead to health consequences, so some examples and science about where that threshold exists and how one might avoid getting there would have been far more useful than just saying “it’s not water fluoridation’s fault”.
I think this article is on the right track, but it’s not actually science-minded enough because the author misses opportunities to be clear about specific things and isn’t convincing about the science involved, because it’s too ambiguous and unabashedly biased from the beginning.
I believe I was in junior high when the southern Illinois town we lived in began to discuss water fluoridation. My mother was quite vocal in her opposition because, “If it hardens teeth, what’s it going to do to your stomach?” I don’t remember that being a common argument, but Mom repeated it often, and so far as I remember it was her only point about the issue.
Both my parents had false teeth by their forties. I’m seventy-five and still chew with my own teeth. ‘Nuff said, so far as I’m concerned.
The four comments so far reinforce a conclusion I’ve reached and sometimes voiced, but which skeptics and those of scientific and logical bent too often reject: Namely, that they argue with the brain, and refuse to hear, or reject, the motivators from emotion.
Take, for instance, resistance to GMO foods. The main argument against them lies in freedom of choice, and the other ‘ecological’ or ‘safety’ arguments — which may or may not have some validity — are actually mere pretexts. The conclusion ‘heck no to GMO’ was reached first, and then rationales are martialed or fabricated to back it.
Advertisers understand this. In our consumer society, a consumer can and does purchase a product or not, for any reason including the entirely irrelevant or irrational, e.g.: it tasted good; it’s locally produced; it costs less; it costs more (therefore ‘must be better’); the neighbours all have it; none of the neighbours have it, and will envy me; I like the colour of the package or the snappy slogan; a likeable actor or an ‘influencer’ shills for it; it’s Tuesday and so why not.
By buying (or not) this product, I demonstrate my ‘freedom’; or I engage in ‘virtue signalling’; or I express solidarity with a ‘community’ (oh, that overused and abused word!).
Against these emotional factors, the gods strive in vain ….
Recent research published by JAMA:
Association Between Maternal Fluoride Exposure
During Pregnancy and IQ Scores in Offspring in Canada
https://jamanetwork.com/journals/jamapediatrics/fullarticle/2748634/
I’m not against fluoride treatment, but in doing it wisely… topically on the teeth once they have erupted… not in our water supply ~
1. Does the addition of fluoride accumulate in the groundwater and in our soil? In what way does this effect microbes or soil health?
2. How does this additional fluoride affect plants and animals and the condition of our soil?
3. Despite all the water fluoridation, tooth decay remains one of the most common diseases.
4. Who is behind the business of fluoridation – a big business indeed that sells a consistent stream of it to most all water municipalities.
5. According to ADA, it is dangerous for children to swallow fluoride toothpaste when brushing their teeth
6. Since it is now known that the effect of fluoride is topical, the notion of an “adequate daily intake” ingestion is flawed. One of the key concerns about water fluoridation is the inability to control an individual’s dose of ingested fluoride which brings into question the concept of the “optimal dose.”
5. Currently, about 41% of children in the United States, where water has been fluoridated at an average level of 1 ppm, have varying degrees of dental fluorosis—levels of over 50% in some fluoridated areas!
6. Fluoride is a known enzyme disruptor. It interacts actively with positively charged ions such as calcium and magnesium. In industrial settings, hydrofluoric acid poisoning is usually treated with intravenous calcium gluconate as such poisoning is associated with acute hypocalcaemia. As with calcium, magnesium plays important roles in optimal bone and teeth formation. By competing with magnesium and calcium in teeth and bones, fluoride deranges the delicate bone formation and bone resorption processes. Such derangements, and consequent intensity of fluoride’s adverse effects on bone and teeth, are amplified in malnutrition, calcium deficiency, and magnesium deficiency.
7. Given the uncertainties and debates about effectiveness, efficacy, and the potential for harming health, it is not surprising that community water fluoridation raises important ethical questions. However, these are not restricted to issues of benefit and harm. In addition, community water fluoridation provides policy makers with important questions about medication without consent, the removal of individual choice and whether public water supplies are an appropriate delivery mechanism.
8. Those promoting water fluoridation refer to key legal opinions and ethical assessments often made in the 1960s when there was little questioning of the evidence and a wide acceptance of the benefits of water fluoridation. The Nuffield Council on Bioethics report on Public Health Ethics concluded—water fluoridation presents a number of ethical difficulties due to the poor evidence base, the lack of individual choice, and the fact that it is a universal intervention. As the recent review by SCHER concludes that the balance between harm and benefit in water fluoridation is at best slim and there are more effective interventions for reducing dental decay.
9. Fluoride has modest benefit in terms of reduction of dental caries but significant costs in relation to cognitive impairment, hypothyroidism, dental and skeletal fluorosis, enzyme and electrolyte derangement, and uterine cancer. Given that most of the toxic effects of fluoride are due to ingestion, whereas its predominant beneficial effect is obtained via topical application, ingestion or inhalation of fluoride predominantly in any form constitutes an unacceptable risk with virtually no proven benefit. ingested water is a very inefficient way of delivering fluoride to teeth given its topical effect but is an important cause of fluoride’s adverse effects on human health. Of all sources of fluoride, artificially fluoridated water is the most practical source to eliminate in order to reduce its human hazards at population levels. Indeed, the abundance of fluoride sources ingested by humans, from tea to cereals and condiments, suggest that the prime public health priority in relation to fluoride is how to reduce ingestion from multiple sources, rather than adding this abundant and toxic chemical to water or food.
10. The enthusiasm with which fluoride was introduced as a public health measure in the 1950s is gradually giving way to a more rational analysis of its benefits and costs as a caries prevention technology. This review argues that the modest benefits of ingested fluoride in caries prevention are thoroughly counterbalanced by its established and potential diverse adverse impacts on human health. Due to the abundance of this chemical, it is little surprising that humans ingest or inhale fluoride from a variety of sources.
+++ A much better article on this topic can be found at The Scientific World Journal – “Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956646/
Fluoride is effective at fighting cavities, but it is simply not necessary to ingest the fluoride in order to do so. Use fluoride toothpaste and there’s no need to drink fluoridated water. More importantly eat a diet that promotes healthy teeth and gums (NOT the standard American Diet).
Just like most other health ‘remedies’, fluoridated water is a fix (a less than optimal fix) for a symptom, not the underlying cause of the tooth decay.
”Water flouridation is safe and effective” and ”I do not want my water flouridated” are not mutually exclusive statements. The issue is not if it is safe or effective. The issue is the right to choose or refuse medical treatment for oneself instead of being forced into an unwanted medical procedure by a government. All talk of ”safety” or ”efectiveness” is a red herring to divert attention from the real issue at stake; the freedom to decide for oneself what medical procedures to have.
I use flouridated toothpaste and I refuse to drink flouridated water if any alternative is available. I spend money on bottled water to avoid compulsory medical treatment by well meaning folks who want to force me to take care of my teeth and do not care if I want to or not.
I do not care if it is safe or effective. I care about not having a government decide for me that I MUST submit to a treatment I did not choose. Unless this issue is addressed fouridating the public water supply means that an individual who wants the right to decide must seek other sources of water, even at a high price, if need be, to avoid compulsory medical treatment.