Comment by anyonecancode
21 days ago
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."
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.
The US government isn't forcing people to use fluoridated toothpaste. There's plenty of non-fluoridated toothpaste available if people want it.
Also: fluoride works topically, not when ingested. That implies we should try to deliver fluoride to teeth in a way that is focused on topical application (toothpaste), not ingestion (water supply).
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Nobody is banning fluoride. They’re just deciding not to include it by default in the drinking water.
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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.