In Stanley Kubrick’s seminal cold war satire Dr Strangelove, there’s a wonderfully off-the-wall scene where the increasingly unhinged Gen Ripper outlines his theories about communists polluting his “precious bodily fluids” in an attempt to justify why exactly he’s launched the world into an all-out nuclear war. He states darkly: “Fluoridation is the most monstrously conceived and dangerous communist plot we have ever had to face!”

Of course, Strangelove is a classic black comedy, and this scene was played for laughs back in 1963 to highlight just how tenuous Ripper’s grasp on reality was. Yet, 50 years later, there is still a distrust of water fluoridation and a plethora of conspiracy theories.

Just last month, a Senator claimed fluoridisation was causing cancer and Down syndrome. Hotpress magazine has run articles championing the work of Declan Waugh, who claims fluoride is making us the sickest country in the world.

These are serious, frightening claims that generate column inches and scare quotes, but they crumble under the weight of the most basic scrutiny. Epidemiological studies on fluoridisation have been done for decades, and the overwhelming scientific consensus is the addition of fluoride to water has had a remarkably positive effect on oral health. Despite over half a century of observation worldwide, claims that fluoride causes everything from cancer to diabetes are supported by no peer-reviewed evidence whatsoever. The Centre for Disease Control in the States says “ . . . these reviews provide compelling evidence that community water fluoridation is a safe and effective method for reducing tooth decay across all ages”.



Playing with the facts

Anti-fluoride scare stories are nothing new and appear with predictable circularity every few years. In the 1970s, Dr John Yiamouyiannis attempted to compare cancer death rates in fluoridated and non-fluoridated areas, but utterly failed to adjust for factors known to influence cancer rates, playing fast and loose with the statistics.

In an authoritative rebuke, the National Cancer Institute examined his evidence, and slammed the “errors, omissions, and statistical distortions” in the report, stating “results of this analysis fail to support any suspicion of hazard associated with fluoridation”. A further series of independent reports reiterated this conclusion over the following years. It is telling that, decades later, despite the debunking of Yiamouyiannis’s work, anti-fluoride organisations still quote his conclusions verbatim.

Of course, like anything else, high concentrations of fluoride can be detrimental, and anti-fluoride campaigners frequently misunderstand the importance of dose – fluoride in relatively high concentrations can cause mild dental fluorosis, an aesthetic condition appearing as white streaks on teeth. Very high concentrations, far beyond the level added to drinking water, can cause illness. In countries such as India, fluoride levels in water are incredibly high, not due to any fluoridation project, but rather due to the abundance of mineral deposits.



Tooth decay

Thus, rather than raise the fluoride level, authorities take steps to lower the naturally high levels. Other countries still supplement fluoride into their salt and foodstuffs to reduce tooth decay. This illustrates precisely why some countries do not need to fluoridate their water, exposing the “country X doesn’t fluoridate” argument as merely spurious reasoning, a classic case of comparing apples with oranges and finding bananas.

Nor is fluoride the only addition we make to drinking water. We chlorinate it too, presumably because dying after a drink of tap water isn’t a consequence we’d care to entertain. It could be argued that water fluoridation is unnecessary when fluoridated toothpaste is available, but this ignores the fact that dental care is a function of wealth; in the US, the annual cost of adding fluoride to water is less than $1 a person and is one of the few health interventions that saves much more money than it costs. By contrast, the estimated toothpaste cost is $17 per person, penalising the poorest in society.

While it’s easy to dismantle the arguments of anti-fluoridation campaigners, it is detrimental to the public understanding of science and medicine. One can go through the laundry list of claims, debunking them point by point. Unfortunately, it is big scary claims that generate more interest, and nuanced discussion is easily dismissed.

This is an unfortunate reality we seem to have forgotten from the similarly fallacious vaccination scares of the early 2000s; such irresponsible reportage can cost lives.



Dr David Robert Grimes (@drg1985) is a physicist at Oxford University. He is a keen advocate of the public understanding of science and medicine, and keeps a blog at davidrobertgrimes.com