The Big Scary F Word

Today, we're talking about something that I've noticed is a fear among many parents. It is a fear that starts with the letter "F." But it's not a swear word, oh no. Today, we're talking about fluoride. You may think that fluoride is a somewhat closed case; limited to a minority of conspiracy theorists. But this is sadly not the case. Just recently, a study focusing on the effects of removing water fluoridation in the city of Juneau, Alaska was published. The short is that it caused a lot of cavities at great expense to the public. I also hear a lot from various sources that parents fear their kids coming into contact with fluoride. Generally, this comes from two sources: toothpaste and water. There seems to be much less fear surrounding toothpaste though; and all the arguments generally stem from the water fluoridation concerns. Based on that, I'd like to focus on water and discuss the fears, logical missteps, and data associated with them.

From what I've found, the arguments against fluoridation can be broadly classified into three categories: the freedom argument, the concern argument, and the conspiracy argument. There is, of course, a fair amount of bleeding between these positions and the degree that that takes place can be readily observed in conversation. We'll start with the freedom argument.

The freedom argument essentially postulates that water fluoridation is tantamount to large scale government medication without consent. Of the three arguments this one is likely the strongest. Though it's strength relies on the majorly subjective interpretation of things like freedom. There is nothing that this camp "fear" by and large aside from, perhaps, the removal of the choice of whether or not to consume the fluoride (though for many, this is not really a choice anyway because the water naturally contains fluoride). So let's look at the specific claims and why they have some issues. First that the freedom of choice is taken away from the individual. There is a bit of a false dichotomy here as well as reductio ad absurdum (reduction to the absurd). To claim that, because they don't have a choice in municipal drinking water, they don't have a choice at all is certainly not the case. There are plenty of ways to get water free of fluoride if it is truly a concern. A contrary argument to this might be that not everyone can afford different sources of water. This fails to take into account that for every $1 spent on fluoridation, $38 of dental costs are saved. So it is actually putting the less fortunate in a better financial situation, rendering the counterargument moot. Next for this argument is the issue of consent. There is no question that fluoride, as it is being used to prevent a medical condition (namely tooth decay), that it can be classified as a form of medication. However, it can be argued that the act of voting in representatives that can evaluate and make these decisions (i.e. what goes into our water supply) is in and of itself a form of consent. Whether or not you subscribe to this interpretation is, of course, your choice. But it is always good to consider these options. The final thing that those using this argument need to consider is the old Vulcan adage, "the needs of the many outweigh the needs of the few or the one." I.e. do the freedoms of the individual outweigh the well being of the community. Though this is, again, a personal view, it seems reasonable to conclude given the downsides of fluoridation are almost nonexistent and the benefits, both medical and financial, are large any rational individual would opt in to it anyway.

Next is the concern argument. I have found that most parents that are worrying about their children tend to use arguments that are found in this category. The concerns can come from many sources. Those trying to push an agenda will often cite cherry picked data and arguments from sources such as a National Research Council report, EPA statements, and WHO reports. Invoking the naturalistic fallacy is also common, despite the prevalence of fluoride in natural, untreated water. These inevitably get picked up by parents who develop a genuine sense of concern for their child's well being. That argument, the one we'll focus on here, is essentially that people get worried that their children are ingesting fluoride. This however is not a big concern. We can actually do the math to show why.

• Fluoride is estimated lethal in doses of about 5-10 g in an adult (at or around 70 kg). To put that in perspective it's about the same as caffeine. The danger comes from its ability to disrupt electron transport and calcium metabolism.
• In municipal drinking systems the WHO suggests 1.5 mg/L of fluoride in the form of hexafluorosilicic acid and/or salt sodium hexafluorosilicate in to the water.
• To put that in perspective there is only 0.03% the lethal dose (assuming the low end of 5 g). In other words you'd have to drink 3333 and 1/3 liters (ca. 880 gallons) to achieve the low end of fluoride toxicity from water.

So, in short, there's not much to be concerned about where having your child drink the tap water is concerned.

The final, and weakest, argument is the conspiracy argument. The main thinking here is that the government is using fluoride as a form of mind control. There is, of course, not a shred of evidence to support this. As with any grand conspiracy it suffers from the "too big to not fail" problem. Elucidated in a paper by David Grimes, this effectively states that most grand conspiracy theories, in order to function as claimed, would have to reach a number of participants that would make the conspiracy guaranteed to fail. Frankly, if your going to be making decisions for your children, conspiracies should be given a wide berth.

As for me, my kids drink tap water more than anything else. I have absolutely no concern about what that will do to them. I know that they are going to have strong, healthy teeth and that is something I am proud I can provide for them.