Comment by naasking
21 days ago
> Except it's not—fluoride in the drinking water concentrations is proven safe and it doesn't affect brains.
You mean like this: Fluoride Exposure and Children’s IQ Scores A Systematic Review and Meta-Analysis, https://jamanetwork.com/journals/jamapediatrics/fullarticle/...
"Findings: Despite differences in exposure and outcome measures and risk of bias across studies, and when using group-level and individual-level exposure estimates, this systematic review and meta-analysis of 74 cross-sectional and prospective cohort studies found significant inverse associations between fluoride exposure and children’s IQ scores. [...]"
Maybe you should reconsider that what you heard once was the definite truth.
Isn't this talking about naturally-occurring fluoridation, not added? The concentrations they describe as having an inverse affect are far higher than what gets added to water on purpose:
What the study measured:
"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"
And what the US federal government recommends (or I guess soon, previously recommended):
"Through this final recommendation, the U.S. Public Health Service (PHS) updates and replaces its 1962 Drinking Water Standards related to community water fluoridation—the controlled addition of a fluoride compound to a community water supply to achieve a concentration optimal for dental caries prevention.1 For these community water systems that add fluoride, PHS now recommends an optimal fluoride concentration of 0.7 milligrams/liter (mg/L)" [1]
Note, too, the study's section on Study sample;
"No studies were conducted in the United States."
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC4547570/
The source of fluoride is irrelevant, the effect of fluoride is cumulative. If you're getting half of the "harmful dosage" just from your water, you're much more likely to pass that threshold than if the water had no fluoride. In nations with easy access to fluoridated toothpaste and where dental hygiene is common, the cost-benefit is not at all clear.
If the source of fluoride is irrelevant, then shouldn't fluoridated toothpaste also be banned as a result of harmful dosages? Even assuming someone spits out said toothpaste, they are still increasing the fluoride levels in their body.
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If people getting under 2mg/L were getting harmed, doesn't it seem logical that people getting 0.7 mg/L would also get harmed, just by a smaller amount?
Not necessarily. For instance, if you take enough ibuprofen you'll suffer liver damage, but it doesn't follow that a smaller dose you'll still suffer damage.
I only really have enough general understanding of chemistry and biology to note that dosage generally is pretty important and often non-linear in its effects -- I write JavaScript, not drug formulations -- but "dosage makes the poison" has always struck me a good general purpose aphorism to keep in mind.
> 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;
So this study found no negative effects on IQ when the fluoride concentration is less than 1.5mg/L
The U.S. Public Health Service recommends 0.7mg/L of fluoride[1]. This study supports the idea that the amount of fluoride used in the US drinking water is safe.
I couldn't find any information on how much fluoride is in utah drinking water as a whole, but a report from Davis County shows that they stay between 0.6mg/L and 0.8mg/L [2]. I'd say its fair to assume basically all the water in Utah doesn't have too much fluoride, and if it did, lowering the amount to 0.7mg/L would be enough to address the health concerns.
1: https://pmc.ncbi.nlm.nih.gov/articles/PMC4547570 2: https://www.utah.gov/pmn/files/962361.pdf
https://news.ycombinator.com/item?id=43525098
Hah. Maybe, as noted by others, you should read the study cited before assuming its conclusions support your argument. Which they do not.
I think you should read it. It literally says fluoride in higher concentrations is linked to lower IQ. It says there is insufficient evidence to draw any conclusions in lower concentrations. NOT that fluoride in lower concentrations is definitely without a doubt safe. It leaves open the question. And, it studied fluoride in urine, which means even if the drinking water levels in the US are in the “insufficient data” range, the cumulative effect of multiple sources of fluoride is still a factor.
Also note that in reality 0.7 mg/L is the “low” value and 1.5 mg/L is the high water mark from the study. That’s not a huge window by any means…
Maybe apply some critical thinking and notice that the water levels from fluoridation add on top of any other sources of fluoride people ingest, eg. toothpaste, food, etc.
That is not a study of drinking water concentrations, but much higher naturally occurring levels. Its also has pretty poor confidence intervals:
https://journalistsresource.org/home/how-to-read-this-study-...
https://jamanetwork.com/journals/jamapediatrics/article-abst...
I would be careful throwing a single study around as proof of anything, here is one with a different conclusion:
https://journals.sagepub.com/doi/full/10.1177/00220345241299...
The source of fluoride is irrelevant, the effect of fluoride is cumulative. If you get 0.7mg/L from drinking water and then add toothpaste and other sources, you could easily surmount the level where harmful effects occur.
You are making a lot of assumptions to fit your narrative, the higher natural source would also be cumulative with toothpaste etc.
There is no conclusive data to support your assertion and there is a lot of data to support the benefits of fluoridation.
Did you actually read any of what I posted to understand it or is your mind already made up?