Perhaps more could be done. The situation is complex because of several compounding factors for sure. There are European countries that have no water fluoridation and better oral health outcomes than in North America.
Regardless, there’s 10 years where a city in North America turned off water fluoridation and we have results of that decision to study.
I'm skimming the results, but it looks like adult teeth had less cavities when they turned the fluoride off...and that was not observed in Edmonton where they left the fluoride on the whole time.
"For all tooth surfaces among permanent teeth (Table 1a), there was a statistically significant decrease in Calgary, for the overall mean DMFS, which was not observed in Edmonton."
Based on their data, you could argue that fluoride increases cavities in adults... I'm not making that argument. I agree with you in that I think confounders are at play and the difference attributed to fluorinated water isn't as large.
People will use this study to take about the rampant tooth decay in Calgary, ignoring that there is roughly as much decay in Edmonton which had the fluoride on the whole time.
Before calling them "anti science wackos", why not review the evidence or cite some of your own. Ironic that the "wackos" seem to be the only ones providing any evidence for their claims.
There is high quality evidence that fluoride at levels contained in some US water supplies is associated with lower childhood intelligence. For lower levels, the conclusion is "we don't know", not that there is no harm.
There is also high quality evidence that in the age of fluorinated toothpaste, fluorinated water "may slightly" improve dental health.
“The evidence suggests that water fluoridation may slightly reduce tooth decay in children,” says co-author Dr Lucy O’Malley, Senior Lecturer in Health Services Research at the University of Manchester. “Given that the benefit has reduced over time, before introducing a new fluoridation scheme, careful thought needs to be given to costs, acceptability, feasibility and ongoing monitoring."
The literally bold-faced conclusion of your article is that no evidence exists that community water fluoridation affects childhood IQ.
We have a natural experiment running for 80 years where each arm of the experiment has N > 100e6. If there was going to be evidence of community water fluoridation lowering IQ, it would have emerged by now.
"The NTP monograph concluded, with moderate confidence, that higher levels of fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children".
They found drinking water with levels that lowered IQ. The actual conclusion was that higher levels (that were found in drinking water) lower IQ.
For lower levels the conclusion is we don't know how it effects IQ. The actual bold face conclusion is "More research is needed to better understand if there are health risks associated with low fluoride exposures".
The National Toxicology Program’s monograph failed peer review by the prestigious and independent National Academies of Science Engineering and Medicine. In fact, the document failed peer review twice:
It seems that this team found what they wanted to find. Are they scientists or ideologues? Were they creating the 'evidence' for the San Francisco trail?
Please define appropriate levels and then cite some evidence that proves with high certainty that level is safe.
For the sake of argument, assume that only 1% of the US has levels that harm IQ. Would it not be worth it to remove fluoride from the water to improve the intelligence of 1% of the population? Especially when you consider we can get fluoride from toothpaste?
"The NTP monograph concluded, with moderate confidence, that higher levels of fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children"
They found fluoride in drinking water concentrations was associated with lower IQ, the opposite of your claim of "proven safe".
Show us some evidence that is proven safe, so far as I can tell all evidence points to unsafe or "we're not sure".
> What needs to stop happening is people ignoring objective reality just because the results happen to align with the other "team's" position on something.
I couldn't agree more. The study that is cited above started when Obama was president by the way.
Why did you omit the sentence immediately after the one you quoted?
> The NTP review was designed to evaluate total fluoride exposure from all sources and was not designed to evaluate the health effects of fluoridated drinking water alone.
…or the following sentence, which they bolded to ensure the reader wouldn't miss it?
> 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.
So no, they very explicitly did not find that fluoride in drinking water concentrations was associated with lower IQ.
I see the goalposts are moving from "fluoride in drinking water concentrations" (implication: concentrations commonly found in municipal drinking water) to "fluoride in drinking water at certain concentrations" (i.e. any arbitrary number that could support your position).
Anyway, there's a pretty obvious definition of "drinking water concentrations": the recommended amount for US drinking water. Again, the authors of the study bolded this sentence to ensure you wouldn't miss it:
> 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.
My first sentence in my original post was " The conclusion from the largest and strongest studies is that there is a certain level of fluoride that harms IQ." I did not move the goal posts from there.
I was replying to a comment that said "fluoride in the drinking water concentrations is proven safe" (there is actually no proof of this).
I never claimed that all fluoride levels harm IQ.
It's great that the US recommends that fluoride doesn't exceed levels that are proven to harm children's IQ, instead they only recommend levels for which there is "insufficient data".
I suppose we will ignore the people who are still drinking water with levels above what is known to be harmful.
To be clear, about whom exactly are we talking here? Who are the actual people drinking water with known harmful levels of fluoride that we’re ignoring?
If we take the known harmful level of fluoride as being >1.5mg/L then the NTP monograph itself has some information ():
> areas including central Australia, eastern Brazil, sub-Saharan Africa, the southern Arabian Peninsula, south and east Asia, and western North America (Podgorski and Berg 2022). Regions of the United States where CWS and private wells contain natural fluoride concentrations of more than 1.5 mg/L serve over 2.9 million U.S. residents (Hefferon et al. 2024). The U.S. Geological Survey estimates that 172,000 U.S. residents are served by domestic wells that
exceed EPA’s enforceable standard of 4.0 mg/L fluoride in drinking water, and 522,000 are served by domestic wells that exceed EPA’s non-enforceable standard of 2.0 mg/L fluoride in drinking water (USGS 2020).
[https://ntp.niehs.nih.gov/sites/default/files/2024-08/fluori... Page 2 or Page 22 of the PDF]
Note in the US this is almost all people drinking well water. So if we take the known harmful level at 1.5mg/L, then there are lots of people known to be drinking water above these concentrations. I'm not sure I would say we're necessarily ignoring them, but could argue regulations aren't up to date: the current EPA MCL is 4.0mg/L and secondary MCL is 2.0mg/L.
For more in depth data, we can take the EPA's Review of Fluoride Occurrence for the Fourth Six-Year Review (2024) [https://www.epa.gov/system/files/documents/2024-04/syr4_fluo...]. Page 15 of the PDF shows artificially fluoridated water nowadays has fluoride concentrations between 0.6mg/L and 1.2mg/L. Page 18 shows that ~4.7 million are being served with concentrations of fluoride >1.5mg/L. This is higher than the Hefferon et al figure but it seems this figure is based on data from 2006-2011 (where the population was lower, but also the recommended fluoride concentration was higher, with the max at 1.2mg/L pre-2015). I also am not convinced Hefferon et al has any figures on private wells (although maybe I misread the paper).
Anyone who talks about who was President when a study was done is immediately clarifying for you that they have a political agenda.
If there’s a problem with a study, or a study is particularly strong, that should be due to something about the study itself (methodology, significance of results, etc), not its political environment.
To emphasize your point, I don't think anyone will notice if someone's alzheimers is 2.3% better.
These rating scales like CDR-SB (invented by drug companies or researchers who are funded by drug companies) are very good at making the tiniest improvement sound significant.
From what I've read, those drugs are very good at removing amyloid, but despite that, they don't seem to make much of a noticeable (clinically meaningful) difference in the people treated with them. I personally would not call that a "huge success".
If they are so good at cleaning up the amyloid, why don't people have more of an improvement? I think everyone agrees amyloid is associated with Alzheimer's, the question is how much of a causative role does it play.
From what I've read, those drugs are very good at removing amyloid, but despite that, they don't seem to make much of a noticeable (clinically meaningful) difference in the people treated with them. I personally would not call that a "huge success".
After many decades of research, we've gone in the last few years from no ability whatsoever to affect the underlying disease, to 30% slowdown. To be clear, that's a 30% slowdown in clinical, cognitive endpoints. Whether you call that "meaningful" is a bit subjective (I think most patients would consider another couple years of coherent thinking to be meaningful), and it has to be weighed against the costs and risks, and there's certainly much work to be done. But it's a huge start.
If they are so good at cleaning up the amyloid, why don't people have more of an improvement?
No one is expected to improve after neurodegeneration has occurred. The best we hope for is to prevent further damage. Amyloid is an initiating causal agent in the disease process, but the disease process includes other pathologies besides amyloid. So far, the amyloid therapies which very successfully engage their target have not yet been tested in the preclinical phase before the amyloid pathology initiates further, downstream disease processes. This is the most likely reason we've seen only ~30% clinical efficacy so far. I expect much more efficacy in the years to come as amyloid therapies are refined and tested at earlier phases. (I also think other targets are promising therapeutic targets; this isn't an argument against testing them.)
I think everyone agrees amyloid is associated with Alzheimer's, the question is how much of a causative role does it play.
To be clear, the evidence for the amyloid hypothesis is causal. The association between amyloid and Alzheimer's has been known since Alois Alzheimer discovered the disease in 1906. The causal evidence came in the 1990's, which is why the scientific community waited so long to adopt that hypothesis.
Reading between the lines if we gave people those drugs before they show any symptoms we should be able to do even better. Has this been tested? How safe are those drugs? What should the average person be doing to avoid accumulating amyloids in the first place?
There were some earlier prevention failures with solanezumab and crenezumab, but these antibodies worked differently and never showed much success at any stage.
How safe are those drugs?
There are some real safety risks from brain bleeding and swelling, seemingly because the antibodies struggle to cross the blood-brain barrier, accumulating in blood vessels and inducing the immune system to attack amyloid deposits in those locations rather than the more harmful plaques in brain tissue. A new generation of antibodies including trontinemab appears likely to be both more effective and much safer, by crossing the BBB more easily.
What should the average person be doing to avoid accumulating amyloids in the first place?
There's not much proven here, and it probably depends on your individualized risk factors. There's some evidence that avoiding/properly treating microbial infection (particularly herpes viruses and P. gingivalis) can help, since amyloid beta seems to be an antimicrobial peptide which accumulates in response to infection. There may also be some benefit from managing cholesterol levels, as lipid processing dysfunction may contribute to increased difficulty of amyloid clearance. Getting good sleep, especially slow wave sleep, can also help reduce amyloid buildup.
Would it be fair to say that it's causal in terms of process, but perhaps not in terms of initiation?
That is, there's a feedback loop involved (or, likely, a complex web of feedback processes), and if a drug can effectively suppress one of the steps, it will slow the whole juggernaut down to some extent?
Am reminded a little of the processes that happen during/after TBI - initial injury leads to brain swelling leads to more damage in a vicious cycle. In some patients, suppressing the swelling results in a much better outcome, but in others, the initial injury, visible or not, has done too much damage and initiated a failure cascade in which treating the swelling alone won't make any difference to the end result.
I’m not sure I understand the process vs. initiation distinction you’re asking about, but yes I do believe there are other targets besides amyloid itself which make sense even if the amyloid hypothesis is true. Anything in the causal chain before or after amyloid but prior to neurodegeneration is a sensible target.
I have also heard that because artificial sweeteners increase insulin levels without increasing blood glucose to the same extent that sugars would, this leads to a blood sugar drop which induces increased eating.
On some quick googling the mean debt at graduation from medical school is about 250,000 (this includes undergrad). This number is trending upward. There is also the opportunity cost of 4 years additional school and 3-7 years of getting paid 60-70k.
Most doctors end up making between 265k and 382k per year, this varies wildly (from pediatrician on the low end to brain surgeon on the high end).
Everyone is going to get a bad back at some point if they don't take care of themselves.
"Eat right and exercise " is very generic advice, but it's cheaper than an MRI and will prevent more disease.