On July 11, the Santa Fe City Council voted to stop adding fluoride to the municipal water system, despite dentists’ insistence that it’s a cheap, effective means of preventing cavities. On July 25, it rescinded that vote; a new hearing is set for Aug. 28. George Johnson, a veteran New York Times science reporter and editor of the Santa Fe Review, talks with SFR about what’s behind the great “fluoride conspiracy.”

SFR: You just returned from a "science literacy" meeting in Aspen. What was that about?

GJ: Basically, they were trying to come up with a plan for improving scientific literacy among the public through education and so-called public outreach—I hate that term. That was the gist of it, and then part of the discussion involved, What do we mean by science literacy? And there was this feeling that it's not so much what you know. You could be scientifically literate and not be able to recite Newton's laws, for example, but you should have a sense how the scientific process works: You have a lot of people working on all these little problems and people posing hypotheses and then testing them against experiments or against observations, like when you do an epidemiological study of something like water fluoridation.

Through all this give and take, something like a consensus of knowledge or a preponderance of scientific opinion often emerges. So my example would be, in the case of water fluoridation, that's what's happened since sometime in the 1940s, when they started doing these studies when they noticed that communities with natural fluoride in their water seemed to have significantly fewer cavities than communities that didn't. I think the number from some study was like 40 percent.

None of this is perfect science because it's really hard to do a controlled experiment. You'd have to find two communities where everything was perfectly equal except for the amount of fluoride in the water, and somehow adjust for the fact that people have different habits as far as how many cookies they eat and how often they brush their teeth, and that would probably be related to education levels, would tie in with public health.

So it's really hard to have one single, smoking-gun study, but you have all of these studies that are pointing in this one direction, and it's been enough to convince the public health community that fluoridation's a good thing.

So being scientifically literate means appreciating, 'This is how science works.' And it's always going to be the case that there's going to be an outlier—some study that pops up that doesn't seem to show that fluoride is effective, or suddenly calls into question safety at much higher levels of fluoride, and then you have to take that all into consideration—which it is, and these groups like the American Public Health Association, they continue to recommend fluoride.

But the opposite of that approach is you decide—in this case, probably mostly for political reasons—fluoridation is bad; you don't like the idea of the government or any kind of pointy-headed experts or anyone deciding to put fluoride in your water. It's sort of like those evil people with the Obama administration trying to make you have health insurance. You resent that as this encroachment on your freedom to decide whether you have fluoride in your water. So then you go out on the Internet and you search water fluoridation and you find little scraps that support your position and you ignore everything else—and that, of course, is not science.

That in itself is interesting to me. It sort of seems like this whole thing is actually a psychological issue instead of a chemical issue.

Yeah, that's well put.

Does the Internet, the freedom of information that's out there, create more scientific echo chambers in which there's always a scientific study to counteract somebody else's? And then how do you get anywhere?

Yeah, you know, you can always find this stuff, and people don't look at it and see what the quality of the study is compared with the others and—you know, so echo chamber is a really good word. And then also, the way these things work, if you're an advocate against something, whether it's cell phone emissions or fluoride in the water, you're going to put together a website and many more people—you know, people don't go to the Internet very often because they want to find information supporting fluoride because they just kind of take it for granted that this has been done for half a century throughout the United States, and then they don't really question it.

So then the people that go searching are searching for the negative information—and then, conveniently, there's a group like the Fluoride Action Network that picks and chooses among the evidence, and people find this site right off.

Do you think—I'm googling fluoride now because I'm just curious—yeah, the Fluoride Action Network is the second-highest hit.

And the first one's probably Wikipedia. Exactly. Yeah. And Wikipedia's usually a pretty good source; it just depends on how many people care about the page and maintain it, so if you get some kook that puts some misinformation, you get somebody else correcting it.

It's easy to see how this is self-perpetuating and kind of self-reinforcing, but I'm curious: Why now? Why Santa Fe? Why Albuquerque?

I got an email from someone telling me how stupid I was—from a guy in Fairbanks, Alaska, which apparently recently voted out fluoride too. There was an article about Florida where it was basically St. Petersburg, Tampa—that county voted to stop fluoridating the water with similar arguments.

I think it's tied into two things. One is the Tea Party phenomenon: this idea that you don't want the government doing anything that has to do with social programs or deciding for you what the social good is, and they use words like "forced medication" to talk about putting fluoride in the water.

Fluoride is already in the water at different levels; some communities have much more fluoride than the standard, and there's a few places—like, there was a big study in China, where they have such high fluoride levels in the water that people actually have cosmetic effects, like fluorosis in their teeth.

So anyway, it's really supplementing something that occurs naturally in water, but they look at it as forced medication, so it invokes all these ideas of the government putting stuff in your water to control you. And people actually make this claim, that it's part of some mass mind control—people who are really far out there. And for other people, they just don't like—they feel there's a principle here, that you're taking away people's right to choose whether they imbibe fluoride or not, because they can always buy fluoridated toothpaste.

What's the other thing?

Oh! Santa Fe's obviously not a stronghold of the Tea Party, but there are people here, and it overlaps also. That's what's interesting: The right-wing Tea Party stuff overlaps, in a lot of places, with this kind of New Age idea that—this sort of obsession with everything that's natural and suspicion of anything that's technological. It fits in with the whole health-food thing and then the idea that any kind of established medicine or established health guidelines is probably suspect and that the best way, and that these people are all part of not necessarily a conspiracy—although some people would say that—but this dominant force, this establishment to tell you what's good for you, mainstream medicine, the whole allopathic versus homeopathic medicine.

So people believe that mainstream science and mainstream medicine has its own agenda and you need to get back to the Earth with natural remedies. So I think it's similar to that, because I'm sure you'll find that people that are going to be coming to this hearing to talk against fluoridating the water probably also think that the waves from their cell phones are causing bad effects on them, and they probably have multiple chemical sensitivities and just the whole fibrous neuralgia or something—there's this whole kind of body of these quasi-syndromes. It doesn't mean that these aren't real complaints that people have, but they're searching for answers and grasping at straws and coming up with these things. Or chemtrails, you know…

You did a lot of reporting on the Firstenberg cell phone emissions issue. Do you see parallels? And also, should we worry that our city officials haven't really progressed beyond just saying yes to whatever sounds the scariest?

I think that really is the problem. You know, you can always make this argument. There are studies, and the more you dig into these and actually look at the studies, everything with epidemiology is really imperfect. So there's this big study that I found—I don't know why I'm doing this; I don't care if they fluoridate the water or not, but it just bugs me when things like this come up and they're not really being based on rational, scientific argument.

But there was this big study in the UK that was commissioned by the government. it came out recommending fluoridation—I guess it's very controversial in the UK as well, fluoridation, or has become controversial—and the study decided that, according to the best evidence, fluoridation is an effective way to prevent dental caries, or cavities.

But then they also noted that the quality of any one of the studies isn't as great as it could be. They talked about A-level studies and B-level studies, and they were saying these were at best B-level studies. So what they mean is, most of this research was done decades ago, and then people figured it was established, and there hasn't been anything like a real solid, nationwide epidemiological study where you control for all these different factors—demographics and everything.

There never is a definitive epidemiological study, but to have something that would come closer to modern standards—you can just count on that observation in the study being picked out, and then the fact that, despite all that, they decided the preponderance of the evidence favored fluoridation to be ignored.

So you'll find things like that.

Another study that just came out that they're making a big deal of is the meta-analysis in China…They really consider fluoridation an issue because of the very high levels that naturally occur. People tried to find two similar villages, and they were correlating it with IQ, for some reason.

Some studies say they found statistically significant differences in IQ between the village with high fluoride and the village that doesn't have it. [Another study] did a meta-analysis and decided there was some indication that high levels of fluoride correlated with lower IQs—which sounds horrible—but when you look into the study, the levels are much higher, as much as 1,000 parts per billion rather than 0.7, which is the recommendation [in the US].

The study noted in passing: These aren't big differences when you're talking about a few IQ points between groups of people. It's not really clear whether that's just experimental noise, experimental error. They're saying it's very possible that this divergence is within the bounds of experimental error, that none of the studies were of high-quality, but it's something that we should definitely keep an eye on.

For one thing, it's this very tentative study that could be wrong. Two, it's not a very big effect—if it is one at all. And then three, it's at very much higher levels of fluoride.

So people will take this and say, 'Well, this shows that there are levels of fluoridating the water to make us stupid so we vote for Obamacare,' when actually no one's talking about putting fluoride at those levels in the water.

I went to some top anti-fluoridation blogs, and often, they take one part of a study and twist it. How does science literacy figure into that? How do we get to a point at which—well, some of that must be willful misinterpretation, right?

Yeah. When you're doing science, the idea is, you usually start with a hypothesis of something you think based on whatever reason—maybe just a hunch that you think is true or, in the case of fluoridation, it was anecdotal evidence and dentists who were just saying they could really tell the difference between communities with and without fluoridated water—and then doing these studies to test and see whether this is true. And then, if the study supports it, you believe, 'Well, this is more likely to be true than it was before,' and then you keep doing these studies.

On other hand, if you find that the evidence goes against it, then you abandon the hypothesis, or you figure there are other factors and it's more complicated than that.

But this kind of distorted citizen science—it's a term I've been kind of playing with. It sounds like a good thing, citizen science, but too often it turns out to be this case where you start with what you think is already true and then find little scraps that support it—so, as you say, you ignore the context of the whole study and what the authors actually concluded, and then you pick on the weaknesses, which always exist, and emphasize that.

Plus, you're just taking this one scrap from one study and not looking at the overwhelming body of evidence.

So I think scientific literacy—one thing someone suggested at this meeting was [that] it includes an appreciation that there's something called a scientific consensus on issues. And it's often imperfect, but where you have the best-trained people with the best knowledge devoting serious time and attention to something—and gathering data, debating it in scientific arena, figuring out what it means—in this, you should probably take the outcome of that more seriously than one isolated study that pops up on the Internet.

Because it's possible that you, the citizen scientist, are gonna go out there and, lo and behold, find something that none of the experts had even thought of or ignored—or, if you're of a more conspiratorial bent, you think that they've suppressed it. Because there's all kinds of just really amazing theories, like that this is all a plot by the chemical industry to figure out something to do with their industrial waste, which includes fluoride. So people will come up w these very paranoid interpretations. But even if they don't, even if they're very earnest and well-meaning and they go out, and whatever they happen to find (or what some advocacy group has put together for them), [one] probably shouldn't give them as much credence as the scientific consensus.

Now, that doesn't mean you have to accept the scientific consensus on blind faith—but if you're going to be making policy decisions that affect a lot of people, that's what you take the most seriously.

Now, the counterargument, which is used a lot by the cell-phone people and the fluoride people—I guess they've used this too—is this whole thing about, they call it the precautionary principle. They say, 'Yeah, it's true that it's not likely that cell phone waves are giving us brain tumors, and it's true that the prevalence of brain tumors has actually been decreasing in the last few decades, but it's possible still; you can't rule out the possibility, and there's a few outlier studies that suggest it, so why would we take this risk? Why in the world—even if there's just the tiniest, tiniest effect that one person might get a brain tumor—would we take this risk? We need to embrace the precautionary principle.'

Which, if you really embrace the precautionary principle, you wouldn't be able to do anything. Everything is a tradeoff.

In the case of fluoride, it seems to me that's kind of a rich man's argument: It's the people who can't afford to go to the dentist who benefit from having it already in the water, right?

Exactly! And that's always been one of the big arguments, that it's a social justice thing because we go out and we buy our fluoridated toothpaste—and in fact it's probably hard to buy toothpaste now that's not fluoridated—but there are very poor children and poor adults who just don't bother, they get no dental [care].

[There's a] percentage of children that get no dental care whatsoever and really suffer from cavities and dental infections. […]

[A local pediatrician] made another point that I hadn't seen, which was—another bit of evidence on the other side is taking countries that don't fluoridate the water, and then they claim that they have no higher or even lower levels of tooth decay than we do here. But it turns out that at least some of those countries, instead of fluoridating the water, they put fluoride in the salt. It's interesting because especially places that are less likely to have public water supplies, they figure the way you're going to reach more people is by fluoridating the salt—like in the United States, they put iodine in the salt.

You've been a journalist for a long time. When it comes to covering stuff like this, what is fair? What is balanced? How do we go about covering it?

One thing that really was a problem in a lot of the coverage of cell phones was just this assumption that there's two equally weighted sides to the story. With cell phones, it gave the illusion that this is a genuine debate in the scientific community that people are wrestling over, when in fact it's not.

There are a few scientists around the world—for some reason a lot of them tend to be in Finland and Sweden; I don't know why that it is—but they come up with studies that they think raise questions about microwave safety, and these are like these little anomalies in this overwhelming body of evidence that it's not a problem.

So it's not balanced to pretend like that side of the story is of equal weight. It's a story to say, 'Here's the preponderance of scientific evidence, and the consensus of the scientific community' and that there are a few questions, but then you put it in context, and that's balanced. But again, where do you draw the line? There's still this guy Peter Duesberg, a respected biologist at Berkeley, who insists HIV isn't the cause of AIDS. So every time you write about HIV and AIDS, it wouldn't be balanced to point this out, because everyone except him thinks it's wrong.

Is it ever self-promotional—scientists just wanting to get their names out there over and over again?

There's definitely self-promoters on both sides. They set themselves up as experts and they like to get quoted—sometimes for good reasons and sometimes for not necessarily bad reasons, but they become the voice for the loyal opposition or something. So yeah, there's that.

With fluoridation, it seems like it's fair and balanced to put the opposition in context and to note that it's politically motivated—or that you can certainly argue that that's where it comes from—and kind of see where it comes from, and then really make the point that you have groups like the American Association for Public Health just deciding again and again, whenever they revisit the studies and the science, that fluoridation is a good thing.

Or if you have a study like this one—the Chinese epidemiological study on fluoride and IQs—again, you point out the weaknesses in the study and the fact that we're talking about different levels [of fluoride].

There's this whole thing—I think it was Paracelsus who said, 'The dose makes the poison': anything taken at certain doses is going to have different effects as when taken at low doses.

Even the evidence for bad effects of fluoride at levels many times higher than what they intentionally put in the water supply—even that is pretty shaky, and the worst thing that comes up is the cosmetic things. And then you get much shakier evidence that's not really at all accepted for other things. Like cancer? Yeah, like kidney cancer is one that comes up.

I'm writing this book about the science of cancer, and when you start looking into these things, you can find evidence that anything causes some kind of cancer at some kind of level. Because the fact is that people just get cancer. There's always going to be factors that a certain number of them share, but whether that's actually a causal effect is really, really hard to pin down—unless it's something really egregious like smoking tobacco.