> 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.
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).
> Also: fluoride works topically, not when ingested.
wrong[1]
[1] https://www.cdc.gov/oral-health/data-research/facts-stats/fa...
When I say "fluoride works topically, not when ingested", I mean there's no benefit to teeth from swallowing fluoride, the only benefit to teeth is from it touching teeth directly. That link doesn't say that there's a tooth health benefit from swallowing fluoride.
Both toothpaste and water supply cause some fluoride to touch the teeth (topical) and some fluoride to be swallowed (ingestion). However, toothpaste has a higher ratio of topical application to swallowing, vs water supply which has a lower ratio of topical application to swallowing. That's why I said toothpaste is focused on topical application and water supply is focused on ingestion.
I think the common consensus is that the primary benefit of fluoride is topical, not systemic:
* Initially, fluoride was considered beneficial when given systemically during tooth development, but later research has shown the importance and the advantages of its topical effects in the prevention or treatment of dental caries and tooth decay. [The Fluoride Debate: The Pros and Cons of Fluoridation; Prev Nutr Food Sci, 2018; https://pmc.ncbi.nlm.nih.gov/articles/PMC6195894].
* The actual mechanism of fluoride action is still a subject of debate. A dogma has existed for many decades, that fluoride has to be ingested and acts mainly pre-eruptively. However, recent studies concerning the systemic effect of fluoride supplementation concluded that the caries-preventive effect of fluoride is almost exclusively posteruptive. [Systemic versus topical fluoride; Carries Res, 2004; https://pubmed.ncbi.nlm.nih.gov/15153698/]
* As noted by Thorrez, your link does not mention topical application vs systemic ingestion. There is a publication from the CDC however stating that the benefit of fluoride is mainly topical:
> Fluoride's caries-preventive properties initially were attributed to changes in enamel during tooth development because of the association between fluoride and cosmetic changes in enamel and a belief that fluoride incorporated into enamel during tooth development would result in a more acid-resistant mineral. However, laboratory and epidemiologic research suggests that fluoride prevents dental caries predominately after eruption of the tooth into the mouth, and its actions primarily are topical for both adults and children (1). [https://www.cdc.gov/mmwr/preview/mmwrhtml/mm4841a1.htm ; 1999].
This material was covered in depositions for TSCA Fluoride trial in 2018, where Casey Hannan (director of the division of oral health at the CDC) was the examinee for the deposition. A temporary upload of a clip from this deposition may be found at https://0x0.st/8Lom.mp4.
Nobody is banning fluoride. They’re just deciding not to include it by default in the drinking water.
"The bill, signed by Cox on Thursday, prohibits communities from adding fluoride to their public water supplies.
The law does not mention any public health concerns related to the mineral, but Republican state lawmaker Stephanie Gricius - who introduced the bill in the state legislature - has argued that there is research suggesting fluoride could have possible cognitive effects in children."
You're lying through some linguistic convolution. What you said is wrong on a factual level. Communities cannot decide to include fluoride in their water, as that is banned, so fluoride is banned from Utah water. This is what words mean
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.
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.
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…
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?