Cross-Posted, via Science Community.
The study, published in PNAS, examined Wisconsin state testing records, archival information about when Wisconsin cities began to fluoridate their water, and data from the Wisconsin Longitudinal Study, which has followed a random sample of 10,317 high school seniors from 1957 through 2026. Key findings include:
- There is no evidence supporting a connection between community water fluoridation and children’s IQ.
- There is also no evidence supporting a connection between community water fluoridation and cognitive functioning at various points later in life.
- Findings confirm evidence published in previous research which also used a national sample, but considered school achievement test scores instead of actual IQ scores.
I had only ever heard it increased cancer rates moderately while doing some heavy lifting on teeth.
I doubt this study
Numerous previous studies have shown benefits from fluoridation.
This is damning if true…
Or it could just be they don’t have a valid control that doesn’t have some fluoridation so they’re not really measuring any difference. It’s just taken for granted.
What about autoimmune diseases and inflammation? It looks like there might be a link, but they haven’t studied it enough.
Based on the body surface area of humans and animals, and considering the metabolism and absorption of fluoride in rats, according to calculations, the WHO’s safety threshold for fluoride intake from drinking water (1.5 mg/L) corresponds to a fluoride concentration of 10 mg/L in the drinking water of rats. After 1 week of acclimatization, the 150 rats were randomly assigned to 5 groups (n = 30) and provided with drinking water containing 0, 10, 25, 50, or 100 mg/L of fluoride. Although 50 and 100 mg/L are not equivalent to the doses humans are exposed to in natural environments, they are commonly used in animal models of fluorosis and have been widely demonstrated to be robust in rat models of fluorosis [35,36,37]. According to the exposure mode and time of fluoride, it can be divided into three modes: fluoride treatment for 12 weeks (12 w), fluoride treatment for 24 weeks (24 w), and fluoride treatment for 12 weeks and 12 weeks of improve water(12 w12 wi) (Table S1). Rats were euthanized with isoflurane anesthesia at the end of the breeding period.
It looks like there might be a link, but they haven’t studied it enough.
oh please.
There are regions that have been fluoridating water for close to 100 years.
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Fluoridosis is not drinking water fluoride levels, not even close
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Rats are shit models of human effects.
Absence of evidence is not evidence of absence.
Two things can be true at the same time. Fluoride has provided significant benefits to dental health, while it’s effects on the human body are not fully studied.
Modern medicine has numerous gaps when it comes to the chronic illness community, and medical gaslighting is the default experience when people attempt to report symptoms.
Absence of evidence is not evidence of absence, but believing with an absence of evidence is utterly absurd.
I don’t know what conspiracy theory dark hole you fell in, but you definitely need some scientific method and skepticism.
Fluoridosis occurs when fluoride is present in our bodies at a level orders of magnitude higher than what we get naturally or artificially from most water sources.
And you know what happens long before it’s at harmful levels in the body?
Your teeth start to stain from it. And any doctor or dentist who sees fluoride stains on your teeth will immediately jump into action and help you eliminate whatever source is causing the problem. It won’t be your water supply, because that’s more likely to kill you from the other additives than from the fluoride if you drink too much.
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I’m not a biologist, but why is the safety threshold for humans less than 1/6 the concentration as for rats, other than “if a rat dies we’re pretty okay with that”?
Also not a biologist and I’m similarly out of my depth, but I’m pretty sure this part of the quoted text is kind of explaining that, but from the perspective of laypeople like us, is kind of glossing over it.
Based on the body surface area of humans and animals, and considering the metabolism and absorption of fluoride in rats
Surface area and mass/volume don’t scale the same way (for example the square-cube law- a 1inch cube has a volume of 1 cubic inch, and a surface area of 6 square inches, so a 1:1 ratio of volume to surface area,a 10inch cube has a volume of 1000 cubic inches, and a surface area of only 600 square inches, so a 5:3 ratio of volume to surface area )
I don’t know where/how in the body fluoride gets absorbed, but for the sake of argument, let’s say it gets absorbed through your stomach lining, so a big limiting factor in how much and how fast you absorb it is how much surface area the inside of your stomach has. More surface area means absorb fluoride more quickly.
So if rats were just scaled-down humans, you’d expect them to need a lower concentration to absorb the same kind of dose as a human.
But rats aren’t just scaled down humans. They’re rats.
And again, not a biologist, I have basically no idea what the inside of a rat looks like. Maybe their stomachs are roughly the same size proportionally to us, or maybe they’re significantly bigger or smaller, which would throw off how much stomach surface area they have available to they absorb fluoride.
And of course their metabolism and body chemistry is going to be different than a human. I’m pretty sure their metabolic rate is way higher than ours so basically everything inside the rat is happening faster, stuff is getting absorbed faster, but also excreted faster, and food/water is spending less time in the stomach leaving less time for that fluoride to get absorbed.
And maybe rats are just fundamentally better or worse at absorbing and metabolizing fluoride than we are, maybe their stomach lining is just more or less capable of absorbing fluoride, maybe they have more or less of some protein or enzyme or something that does something with that fluoride so it gets used more or less efficiently by their body, etc.
So all of that would need to be taken into account. Whole lot of math involved figuring that out that I don’t even want to think about.
And, of course, experimentally, we want to be able to see and measure the effects. The study is looking for its effects on the brain, not, for example, liver and kidney function (or whatever organs would be damaged by too much fluoride.) Trying to measure the IQ of a rat I’m sure is already hard enough in general, let alone trying to measure potentially very minute changes in it. It may be they’re trying to push the dose as high as they can to try to create any measurable cognitive symptoms, if we’re giving the rats 6x the normal dose, maybe to a level where it might damage their kidneys or something, and still not seeing any cognitive issues, it’s probably pretty safe to say that a normal, safe, dose isn’t going to cause issues either.
Maybe differences in liver or kidney function? I wouldn’t be surprised if various organs are proportioned differently compared to humans because of things like volume vs surface area that come with size differences, and in this case diet.
It looks like that study shows that people who grow up with high fluoride levels in drinking water are more likely to smoke tobacco.
