In the actual research the main "risk" posed by flouridated water is actually fluorosis. This causes minerals in your enamel to be replaced with flouride which can cause them to be brittle in the long term. It's pretty uncommon but the thought is that now that flouride toothpaste are commonplace, the benefit of flouridated water is also way less. Which changes the calculus.
A not insignificant number of researchers are advocating for the view that flouridating water just isn't worth it anymore and the (slight) risk of flourosis is more significant than the (slight) benefit of decreased dental caries.
Children are the main group that benefits from fluoride in water because the fluoride helps strengthen teeth as they form. Lack of fluoride increases childhood cavities, leading to decreased academic performance.
This was a real problem in the San Jose school district until recently. They started fluoridation of water in the last ten years, and were the biggest US city that didn’t fluoridate. The evidence of the above is clear according to SJ dentists I have talked to.
The National Toxicology Program recently completed a fairly substantial meta study and concluded that "for every 1 mg/L increase in urinary fluoride, there is a decrease of 1.63 IQ points in children.". [1] This is also relevant to OP since it's not just pregnant women at risk from excessive fluoridation but also children. For now it seems that adults are, somewhat oddly, unaffected.
> It is important to note that there were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children’s IQ.
Yeah, note the measurement is in urine. So there are two separate issues. Determining whether fluoride is damaging to IQ, and then whether the levels in water can drive this. The former is way easier to evaluate than the latter. The reason comes from that study's intro pargraphs:
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"Since 1945, the use of fluoride has been a successful public health initiative for reducing dental cavities and improving general oral health of adults and children. There is a concern, however, that some pregnant women and children may be getting more fluoride than they need because they now get fluoride from many sources including treated public water, water-added foods and beverages, teas, toothpaste, floss, and mouthwash, and the combined total intake of fluoride may exceed safe amounts."
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So the issue is trying to isolate the exact amount and source of fluoride people are getting. And that probably has no answer because it's going to vary dependent on how much fluoridated water somebody drinks, the rest of their diet, their other dental hygiene composition, and more. So levels that would be safe for one percent of the population, will be dangerous for another percent of it.
Fluorosis is very common afaik. My dentist told me I have it: slightly whiter patches on my teeth. Then he showed me his own fluorosis. It actually is stronger than the old enamel.
Does the study not literally refute the claim that fluoride's negative impact on IQ is lacking in evidence, contrary to the original claim? What exactly do you think needs to be updated?
the original refutation was "fluoride in the drinking water concentrations is proven safe and it doesn't affect brains". Your study does not show that IQ is effected at concentrations that are being added to water supplies. Just because X can result from Y levels of some substance does't mean X results from Y-n concentrations.
> the original refutation was "fluoride in the drinking water concentrations is proven safe and it doesn't affect brains".
No, this is the original claim:
> but it turns out that there are a decent amount of good studies showing a link between fluoride in water and (slightly) lower IQ when pregnant mothers ingest the fluoride.
Then the parent replied that this IQ link is lacking evidence, which it's not, per the meta-analysis I cited.
For fluoride measured in water, associations remained inverse when exposed groups were restricted to less than 4 mg/L or less than 2 mg/L but not when restricted to less than 1.5 mg/L
There were limited data and uncertainty in the dose-response association between fluoride exposure and children’s IQ when fluoride exposure was estimated by drinking water alone at concentrations less than 1.5 mg/L.
The meta analysis you linked gets the strongest results in areas of the world with outstandingly high levels of fluoride and other elements in the ground water .. water with so many additives it rings like a bell when tapped with a hammer (okay, that's an embellishment).
You can’t win. Freedom, IQ, precious bodily fluids. There’s no end to the nonsense.
My city started fluoridating a few years ago. The crazy was off the chart, they’re still active. NYC has fluoridated for 60 years, you’d think someone would have figured out that the entire city is dumber.
But being serious if it’s relatively low and the negative effects only occur during pregnancy it’s not that easy to measure it.
Obviously there is no conclusive evidence (even if the studies from China seem somewhat credible) but IMHO even if the likelihood of this being true is e.g. only 5-10%, risk of a population wide loss of 1-2 IQ points seems like a massively too high price to pay just to slightly reduce cavity rates.
Also dismissing all credible (albeit weak) scientific evidence out of hand just because crazy people hold similar beliefs is a about as stupid as what they are doing..
Well one issue with your snark here is that IQs within the country are going down, and nobody really knows why. [1]
The Flynn Effect was the observation that real IQ scores were increasing over time. But sometime around 1990 this seems to have stopped in pretty much the entire developed world, including the US. I'm not implying that this is solely due to fluoridation, though it's certainly a plausible contributing factor. But as for your snark about 'someone would have figured out people are getting dumber' - well, they have, and we don't know why.
> IQs within the country are going down, and nobody really knows why.
I’m no expert, but I have seen the public education system attacked and defunded for decades, at home and abroad. Even libraries are being shut down in places with enough anti-intellectual sentiment. This goes much deeper than the fluoride in water.
If you can point to IQ values of New York specifically, going down more significantly starting with the introduction of fluoride into the water system, then you might have something there.
Until then, policy discussions like this will continue to take focus from the things that actually have an impact on IQ, like public education, healthcare/nutrition, and poverty.
Education stuff is more of a political talking point than reality. In reality US education spending per student has continually increased and is always near the top of the world. As of 2019 we're 4th in the world for spending on elementary/secondary spending $15,500 per student contrasted against $11,300 for the OECD average. [1] Of course we are having increasingly poor educational outcomes in spite of spending more, more, and more. So if there is a causal relationship between the reversal of the Flynn Effect and poor educational outcomes, it would seem much more likely that the former is causing the latter.
And I'm certain one could trivially dig up data correlating the decline of IQ in New York to fluoridation. The Flynn Effect reversal began in the 90s, and New York began fluoridating their water in 1965, so there's an excellent age correlation there. But that correlation does not necessarily mean causation. What matters are more controlled studies determining definitively whether fluoride is intellectually harmful by using fluoride levels in urine to control for various confounding variables (people in the same regions getting fluoride from multiple sources, consuming more/less products with fluoride, etc). And we do have those studies, and the answer is yes it is.
That certainly doesn't mean it's the sole cause for the reversal of the Flynn Effect as its seen across the developed world, and many countries do not add fluoride to their water. But it is likely a contributing factor. In recent decades we have begun moving far faster than we're capable of evaluating the consequences of, and long-term consequences may well be stacking from multiple sources of mistakes.
> Education stuff is more of a political talking point than reality. In reality US education spending per student has continually increased and is always near the top of the world.
This is disingenuous, and itself a political talking point.
> In reality US education spending per student has continually increased and is always near the top of the world.
It is much more nuanced than “money in equals IQ out”.
Where does the money end up? Not in classrooms, unfortunately.
What is the average ratio of teachers to students? Is this number going up, up, up?
Now do counselors, nurses, etc.
How much are teachers spending out of pocket for classroom supplies? Has this number gone down, down, down?
Yes, it does end up in classrooms. Feel free to look up the metrics you're talking about. Here [1], for instance, is the student to teacher ratio which has continued to decline dramatically over the years. And this difference becomes even more stark when contrasted against many of the countries, particularly in Asia, with substantially greater educational outcomes with far less in the way of every resource.
By "most" metrics the US should be having phenomenal educational outcomes. The one variable that's not controlled for is the quality of students. Also, I put "most" in quotes because it's a weasel word - to my knowledge we outperform on every single typical educational metric, except result.
Flouridation of drinking water does not happen in the entire developed world, though.
And lower IQ scores don't necessarily say much about pure intelligence directly, a worsening education system could also contribute and that's not exactly far fetched. And your linked source says:
> The steepest slopes occurred for ages 18–22 and lower levels of education
Absolutely. And nutrition in general, the internet, and a large number of other factors. Starting around the 90s the world started changing far faster than we were able to measure the consequences of in many different domains. That's even when the rates of autism and other mental disorders also started to skyrocket. That's why I think it's a viable contributing factor rather than the alpha and omega.
But it's relevant here because most people don't know that general intelligence levels (so far as IQ can measure) have begun to decrease, to the point that the GP here was overtly mocking the mere possibility of such as a [implied] practical impossibility.
Do you think bodily autonomy is absolute? Your comments seem to imply that bodily autonomy is the only relevant thing to consider when discussing patient care. The world doesn't work that way. Believe it or not, a doctor won't amputate a limb when you show up with a runny nose even if you insist that that's the procedure you want. Search up the 4 principles of biomedical ethics if you want to learn more about the factors that influence doctors' ethical decisions.
Or do you mean that your opinion should trump that of any doctor or expert in any field when the issue pertains to your person? If that's the case, I wonder why you choose to participate in society at all, given that you're uncomfortable with the idea that other people might know more than you.
No. When decisions I take could affect others, that can, in a limited way, justify overriding bodily autonomy. E.g. preventing someone with an infectious disease from spreading it by quarantining them. Or when they can't make their own decisions, e.g. if they're children, suffering dementia, or are unconscious and time is critical.
> Believe it or not, a doctor won't amputate a limb
I struggle to understand how this is a reasonable, much less charitable, interpretation of my words. Bodily autonomy does not include commanding others. But people can refuse care, even when it is medically sound. Except in very limited circumstances, doctors may not force procedures or medicine on unwilling patients.
> Or do you mean that your opinion should trump that of any doctor or expert in any field when the issue pertains to your person? If that's the case, I wonder why you choose to participate in society at all, given that you're uncomfortable with the idea that other people might know more than you.
One does not at all follow from the other. Experts in the field will tell me excessive sweets are bad for me (and I believe them) - should they get to put a block my credit card so it cannot be used to buy unhealthy snacks, only healthy food?
I have humored your post, now please explain to me: How does believing people have a right to refuse medical treatment imply I am uncomfortable with others being more knowledgeable?
Not just regular toxic chemicals, either, through the is plenty of that. Quite a bit of radiation too.
And companies that adulterate, misrepresent and obfuscate what they put in food as well. No-one is putting corn syrup or brominated vegetable oil in food with any intention other than money money money.
In fact, if I were an evil subgenius and really actively wanted to damage the IQs of the nation for some nefarious purpose, and it has to be substance-based, I'd avoid things with annoying oversight like public drinking water and vaccines and focus on food and pollution as a vector. If challenged, I just say "why do you hate my freedom to make a profit and provide jobs". Sure, the FDA and EPA exist, but even then you can get away with far, far more in those areas. Food wise, HFCS, BVO, etc, pollution wise, almost everything to with plastics or polymers, oil, coal, gas the list goes on and on.
That's just not true. Most of the studies simply compared areas with different amounts of natural fluoride in their local water supply, and applied some basic statistics comparing dental health. There have also been some A/B studies possible in areas that stopped or started using fluoride in their water.
Multiple such studies have been done, globally, over many decades.
There is limited modern evidence (ie. in a world where everyone is brushing their teeth with fluoride toothpaste) of some reduction in tooth decay in children. There were no studies on adults that met the review criteria.
Overall it seems like we just don't really know how much impact CWF currently has.
Fluoridated toothpaste says not to swallow because it contains much higher concentrations of fluoride than drinking water. If you ingest too much toothpaste, it can cause your teeth to get blotchy: https://en.wikipedia.org/wiki/Dental_fluorosis
Yup, but even for fluoride gels it says explicitly not to swallow. One because fluoride is toxic when concentrated, two because it needs to be on your teeth, not inside your belly.
Once ingested, the fluoride has a systemic affect on teeth before they erupt, incorporating into the matrix of developing teeth to increase the mineralization content and decrease the solubility of enamel. [1]
7mg/L? Where the heck did you get that figure?
The correct value is a tenth of that: 0.7 milligrams per Liter (mg/L)
The limit is 2mg/L, and that's only found in places with naturally occurring high levels of flouride.
The people of Flint, MI were (and some still are!) forced to drink bottled water for years when their water was contaminated with lead.
When you drink from publicly supplied water, you accept risks that can be much worse than fluoride in your water. If you want to avoid that, you need to procure your own drinking water.
There isn’t any! GP doesn’t have that authority! Well done!
On the other hand, the society you live in probably has some sort of document establishing who does have the authority, and how it devolves to the actual policy-makers. Google “$YOUR_LOCATION government” and you’ll have some good starting points. If you’re lucky, you might even get to participate in the process; “$YOUR_LOCATION elections” will give you good pointers in that case.
In the actual research the main "risk" posed by flouridated water is actually fluorosis. This causes minerals in your enamel to be replaced with flouride which can cause them to be brittle in the long term. It's pretty uncommon but the thought is that now that flouride toothpaste are commonplace, the benefit of flouridated water is also way less. Which changes the calculus.
A not insignificant number of researchers are advocating for the view that flouridating water just isn't worth it anymore and the (slight) risk of flourosis is more significant than the (slight) benefit of decreased dental caries.