Fluoridation Lowers IQ - Significantly?The argument about whether to fluoridate municipal drinking water is far from over. This is not for lack of study. At clinicaltrials.gov the results of 193 separate studies are given. Of those, 74 were sponsored by industry — mostly toothpaste manufacturers. The other studies were performed under government sponsorship, grants from research institutions, etc. In spite of this long history of research, the latest publications often stir things up by playing into or against prejudices based on previous thought. Consider a recent study performed at Harvard, which indicates that drinking fluoridated water lowers IQ significantly.

That catches your attention, doesn’t it? “Lowers IQ significantly” is a shocker, and the article has instant credibility because it comes from Harvard. But if you interpret that headline to mean that fluoridation turns people into raving idiots, then you have probably not read the article. The average decrease in IQ found in the study was a 0.5 point reduction. The “significant” reduction means that, when the statistical analysis was performed allowing for such things and the natural variation in IQ, the detected half a point reduction among fluoride users is statistically significant. That is, the lower IQ is not an artifact or sampling error within some degree of probability. Determining if that level of reduction significantly reduces the effective intelligence of the population is beyond the purview of the article, but many people skimming through it will interpret the results to mean that fluoridation induces feeble-mindedness. In fact, IQs vary as much as 20 points when a child becomes a teenager according to an NPR article, which is 40 times more significant in some sense. (The IQs shift plus or minus, not always down, as some parents suspect!)

Nonetheless, Fluorides are known poisons. That is not in dispute. So let us talk about poisons. Water in sufficient quantities causes severe pain and/or death. Excess oxygen will kill you. Both are necessary for life. The dosage is important. Poisonous side effects of beneficial intakes are inevitable with everything.

Truly significant IQ reduction is noted in many studies of the effect of cocaine and alcohol on infants. Stress reduces IQ (which might help explain the teenager variations). Sugar is implicated in more disorders than I can shake a stick at. Since all things are poisons in large quantities, we need to consider the optimum dosage of everything we ingest. In this way, we hope to maximize the benefit while minimizing the detriment. Even cocaine has beneficial uses. It is used for several types of medical procedures where the potential harm is inconsequential compared the good: similarly with the other substances.

The case for deciding the optimum dosage for fluoride additives is complicated by the difference between the benefits and costs. Is eliminating tooth decay worth suffering a 0.5 average decrease in IQ? Many people would say absolutely not while continuing to feed their children sugar, exposing them to alcohol and second (or first) hand smoke and maybe being sloppy with seatbelts. What does it mean to have a population decrease 0.5 point? Can that be overcome by lowering the average stress of filling cavities? I don’t know. A good analogy is that we have a fixed amount of money and want to spend it on healthy food. Should we buy all apples or all oranges? Is a mixture better? Maybe we should consider mental health as part of the problem and set aside a fraction of the food money for comfort food or alcohol, which makes us feel better even if it is not making our bodies better. The problem is difficult because, in real life, we must always make comparisons between apples and oranges. Is the tradeoff of lowering or eliminating cavities worth the exposure to nasty side effects? Maybe it is. Suppose you conclude that the benefits outweigh the costs. Then what?

You study all the research and conclude that there is a non-zero optimum dosage for your family; should you be forced to accept it? That is, should government be permitted to fluoridate municipal drinking water? Governmental intervention is different from deciding to use fluoridated toothpaste or not. Compare fluoridating water with inoculation against diseases. We accept mandatory inoculation to protect against childhood diseases, even though in a very small percentage of the inoculations, something goes wrong (not autism — that is bogus ). The difference between inoculation and fluoridation is that by inoculating children, we prevent the spread of disease to innocent bystanders. By mandating preventative measures, we protect more people than just those being inoculated. In contrast, preventing cavities is a more personal benefit even if the results are equally important. Cavities are not contagious like measles.

I have looked at many of the articles cited above and read pro and con advocacy pieces galore. For me, the bottom line is that voluntary use of fluoridation is, over all, a good thing for a person’s health, but forcing it on everybody is a bad thing — especially since alternatives to mass delivery via municipal water exist. The first part of the previous sentence is based on scientific reasoning; the second part after the word “but” is a political statement. You are welcome to challenge either half, but be clear in your own mind if you are responding scientifically or politically.

It has been pointed out many times that more money is spent fighting for and against gun control than is spent on studying whether or not gun control is a good thing. I feel fluoridation is in a similar state. So if you respond to this piece, either pro or con, please cite the source of your information and, if possible, who sponsored the work. There are enough unsupported accusations flying around. I do not want to become a vector for spreading more of them.

CC licensed Flickr photo by cogdogblog