Comment by somenameforme
19 days ago
The study [1] that's based on seems pretty typical, and is precisely what drives skepticism towards these policies. The differences for permanent teeth were not significant. The paper claimed this may be because "7-year-olds have not had the time to accumulate enough permanent dentition caries experience for differences to have become apparent." The differences in temporary teeth had a deft (decay, extracted, filled teeth) of 66.1% in Calgary (no fluoride) and 54.3% in Edmonton (fluoridated).
So you're looking at a small positive improvements in dental outcomes, for what may be a permanent decline to IQ. That's obviously not a trade I think anybody would make, so the real issue is not whether or not it improves dental outcomes but whether it's having measurable effects on IQ as we have seen in other studies. [2] I don't understand why a study operating in good faith wouldn't also pursue this question in unison, or in fact as the primary question. I think relatively few people outright doubt the dental benefits of fluoride, but rather are concerned about the cost we may pay for such.
[1] - https://onlinelibrary.wiley.com/doi/full/10.1111/cdoe.12685
[2] - https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/...
In the 2nd study that shows correlation between fluoride and lower IQ in children, the water had twice as much fluoride as the recommended amount in the US (1.5 mg/L vs 0.7 mg/L).
The only reason for lack of concrete statements on the 0.7 level was a lack of data, owing largely to US political culture (1.5 is the World Health Organization 'safe' limit). Not long ago fluoride stuff was considered a 'conspiracy theory' which greatly deters meaningful scientific research on the topic. This is in part because of social reasons (most people don't want to be perceived as 'fringe') and in part because it results in funding for such research drying up. For that matter even IQ studies themselves are borderline given the US political culture.
So for instance of the 19 low risk-of-bias studies, exactly 0 came from the US. 10 were in China, 3 were in Mexico, 2 in Canada, 3 in India, and 1 in Iran. 18 of those 19 studies found a significant reduction in IQ that corresponds strongly with increases in fluoride (the outlier was in Mexico). With the current administration we'll certainly be seeing funding for such studies in the US and so there should be much more high quality data on the 0.7 level forthcoming. But in general this is a major problem that needs solving. Exploring the breadths of science, including the fringes, should not require an activist political administration.
For that matter even IQ studies themselves are borderline given the US political culture.
This isn't remotely true; it's just something people say on message boards.
7 replies →
There are natural experiments where the correlation between IQ and lower amounts of fluoride can be studied. For example in Israel, until 2014, the fluoride level was 0.8-1.0 mg/L depending on the region but starting in 2014 water is no longer fluoridated (naturally occurring fluoride level is in the 0.1-0.3 mg/L range for the vast majority of the population) so the data should be there, it's just a matter of collecting it. Some countries can provide data for the opposite natural experiment (adding fluoride in recent years).
To me, using the 1.5 mg/L doesn't tell anything about lower levels but it does make me interested in seeing such study whereas before I'd have just dismissed it.
The most ridiculous part is that we have an alternative way to apply fluoride without intaking it. It's called toothpaste. But for some reason people act like Utah is banning vaccine.
Using toothpaste with fluoride can be effective when used regularly as part of dental hygiene. What percentage of the population is going to do this? I've encountered grade school children who have never owned a toothbrush.
Can you answer your own question?