Comment by jiggawatts
20 days ago
I initially dismissed it as the same category of stupid as anti-vax beliefs, but it turns out that there are a decent amount of good studies showing a link between fluoride in water and (slightly) lower IQ when pregnant mothers ingest the fluoride. Note that there is no significant effect after birth.
The idea is to remove fluoride from water and advise pregnant women to use fluoride-free toothpaste.
Everyone else can get enough fluoride from modern toothpastes, or regular dentist treatments.
The logic is that fluoride in tap water made sense in the era before toothpaste had it, but now it is “overmedicating” a vulnerable fraction of the population.
The IQ link is very heavily lacking in evidence.
In the actual research the main "risk" posed by flouridated water is actually fluorosis. This causes minerals in your enamel to be replaced with flouride which can cause them to be brittle in the long term. It's pretty uncommon but the thought is that now that flouride toothpaste are commonplace, the benefit of flouridated water is also way less. Which changes the calculus.
A not insignificant number of researchers are advocating for the view that flouridating water just isn't worth it anymore and the (slight) risk of flourosis is more significant than the (slight) benefit of decreased dental caries.
Children are the main group that benefits from fluoride in water because the fluoride helps strengthen teeth as they form. Lack of fluoride increases childhood cavities, leading to decreased academic performance.
This was a real problem in the San Jose school district until recently. They started fluoridation of water in the last ten years, and were the biggest US city that didn’t fluoridate. The evidence of the above is clear according to SJ dentists I have talked to.
The National Toxicology Program recently completed a fairly substantial meta study and concluded that "for every 1 mg/L increase in urinary fluoride, there is a decrease of 1.63 IQ points in children.". [1] This is also relevant to OP since it's not just pregnant women at risk from excessive fluoridation but also children. For now it seems that adults are, somewhat oddly, unaffected.
[1] - https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/...
In bold from your source:
> 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.
1 reply →
Here is a concise detailed analysis of the concerns with the metaanalysis provided by the NTP:
https://theunbiasedscipod.substack.com/p/the-well-runs-deep-...
The NTP report is flawed and likely biased.
1 reply →
Which changes the calculus
Was that intentional? (https://en.wiktionary.org/wiki/dental_calculus for those who didn't get the reference.)
The canonical form is "I see what you did there".
Fluorosis is very common afaik. My dentist told me I have it: slightly whiter patches on my teeth. Then he showed me his own fluorosis. It actually is stronger than the old enamel.
> The IQ link is very heavily lacking in evidence.
Not really: https://jamanetwork.com/journals/jamapediatrics/fullarticle/...
your study has been heavily criticized where you already posted it:
https://news.ycombinator.com/item?id=43523900
I can only assume once you see those very valid criticisms, you will update your references
5 replies →
[flagged]
What do you mean? There's literally tons of evidence. Do you think fluoride doesn't actually reduce cavities?
33 replies →
7mg/L? Where the heck did you get that figure? The correct value is a tenth of that: 0.7 milligrams per Liter (mg/L) The limit is 2mg/L, and that's only found in places with naturally occurring high levels of flouride.
The people of Flint, MI were (and some still are!) forced to drink bottled water for years when their water was contaminated with lead.
When you drink from publicly supplied water, you accept risks that can be much worse than fluoride in your water. If you want to avoid that, you need to procure your own drinking water.
You can solve your “problem” for a very small price: it costs under $0.50 per day to distill your own drinking water per person.
So for $15/mo, “problem” solved.
Are you doing that?
1 reply →
It's not your water, it's municipal water you purchase with the fluoride in it.
There isn’t any! GP doesn’t have that authority! Well done!
On the other hand, the society you live in probably has some sort of document establishing who does have the authority, and how it devolves to the actual policy-makers. Google “$YOUR_LOCATION government” and you’ll have some good starting points. If you’re lucky, you might even get to participate in the process; “$YOUR_LOCATION elections” will give you good pointers in that case.
> but now it is “overmedicating” a vulnerable fraction of the population.
Makes sense, but the intention also is that many people do not brush their teeth, or at least do not brush them as often as they should, and so fluoride is added to drinking water to compensate so people's teeth don't start to fall out at an alarming rate.
Sadly, an alarming percentage of Americans don't drink water. I’ve spoken to way too many people who think water tastes wrong because it’s not sweet enough.
I've heard this and it doesn't fit in my brain. They never drink water? Ever?
26 replies →
Particularly when traveling, I don't enjoy the taste of tap water. Filtered or (factory filtered then) bottled... and I'm not alone in that viewpoint.
11 replies →
Wisconsin tap water tastes fine. Waco, Texas tap water is really nasty.
1 reply →
I bet those people drink fountain drinks, cofee, tea, etc. made from tapwater.
Maybe instead of removing fluoride from the water they should add sweetener in there along with it /s
I'm pretty sure that no amount of fluoridated water is going to save you if you do not brush your teeth.
Even if the fluoride somehow manages to overcome all that and prevent you from getting cavities, the gum disease will eventually cause all your teeth to fall out.
> many people do not brush their teeth
many? (!!!)
Googling it all I found was one dentist website that said 2%, but didn't seem that reliable
Important sentence is "..or at least not as often as they should" :)
I have no doubt most people brush their teeth in one capacity or another, but do you really think 98% of people brush them regularly and sufficiently? I reckon that drops down quite a few double digits at that point, and since we're talking about populations here that's quite a lot of people.
If that figure is for the US, then that's ~7M people. Feels like "many" to me.
2% is definitely many
The levels of fluoridation in order to cause difference in IQ as I understand it, from the Chinese studies, suggest that basically the effect if true occurs at around 2x+ the concentration found in supplemented water supplies.
My understanding also is that if you’re a dentist wanting to get rich, move somewhere that has unfluoridated water.
2x is basically no safe margin for something like water. Of course you can question the quality of the study, but if it's actually 2x, fluoride in tap water should be treated like lead pipes.
So if your training and double your water intake your basically lowering you IQ? (according to the Chinese studies) I wonder the method this uses.. has anyone looked at dementia rates in high fluoride areas.. Particularly in people with high water intake?
There is also a host of things we use water for from cooking to preserving, distilling and cooling.. i wonder if any of these things could concentrate the fluoride.
Also since fluoride has a lower boiling point any studies tracked what breathing in fluoride gas over long periods cause?
2x is honestly pretty small. I would expect the amount required to drop IQ to be larger by an order of magnitude or more to conclude that fluoridating water is totally safe.
I think that link is only there when the fluoride levels are extremely high. See https://parentdata.org/fluoride-drinking-water/ for a good overview of the data
> I initially dismissed it as the same category of stupid as anti-vax beliefs
Dismissing things out of hand like this is a category of stupid in itself.
Look at the current research, listen to people who devoted their careers to studying this, make up your own mind. If you're on HN, then you're qualified enough to at least figure out who the genuine experts are and read what they recommend.
Putting any science-based debate into a "category" to dismiss is turning yourself into one of the stupid people.
This is bad advice that no one could possibly follow.
> Look at the current research, listen to people who devoted their careers to studying this, make up your own mind.
Do you honestly do this with every single belief you have? Even every single controversial belief? Have you looked, yourself, into whether the world is flat? Whether the 9/11 conspiracy theories are true? Whether crop circles were created by aliens? These are all absurd conspiracy theories, but I assume most people don't know the "up to date" research on any of them, or what people who have "devote their careers" to research them say.
And those are incredibly common and well known to be false theories.
You have to take some things on faith to at least some degree - though to be clear, by "on faith" I mean "on faith of people you trust", which should really start with professional scientists etc. Also, it's totally fine to just say "I have no actual idea" about most things, and just go with what your current understanding of the status-quo position is.
> Even every single controversial belief?
Yes.
> Have you looked, yourself, into whether the world is flat? Whether the 9/11 conspiracy theories are true? Whether crop circles were created by aliens?
Yes.
> Everyone else can get enough fluoride from modern toothpastes, or regular dentist treatments.
The advantage of putting it in water is that it ensures all children get it, not just the children whose parents can and do make sure they brush their teeth and go to the dentist.
So everyone else's kids have to have a lower IQ because of that?
Bad parents are gonna be bad parents.
Agree, my biggest issue is often where they source the fluoride and whether they test it. We found out in my (liberal) hometown that they were actually sourcing some derivative which has no human studies.
Given that everyone gets enough in toothpaste I just don’t see the reason to keep doing it, too much can go wrong. It’s kind of a strange mass medication that I’m not sure the government needs to be involved in.
What was the derivative?
> The idea is to remove fluoride from water and advise pregnant women to use fluoride-free toothpaste.
What most people don't understand here are the levels of fluoride being ingested. You can very easily remove all fluoride from your water with a relatively cheap RO system. But the recommendation to use "fluoride-free toothpaste" is just plain misinformation.
The reason is that you don't eat toothpaste. And even when adults ingest small amounts of toothpaste, again, the amount of fluoride is basically beyond negligible. Fluoride can both be applied to teeth as a varnish and/or consumed in drinking water. Using a flouride-free toothpaste can oftentimes do more damage than good because of SLS in those alternatives and because those alternatives often have abrasives that do far more harm than good. It's amazing people will recommend a product that may likely be worse because they have no domain expertise. So, yes, people should talk to their Dentist about these things and ask questions of them vs the Internet.
Really the downside to removing fluoride from city water is that low income families will be worse off with respect to dental related issues compared to more well off families that spend time instilling dental hygiene and preventative care for their kids. As you mentioned most people who have decent oral hygiene get enough flouride.
Where we live we have well water. Fluoride in the water isn't a concern, and if it was in our drinking water it generally wouldn't be consumed because of the water filtration anyway.
Source: spouse is a DDS.
My anecdotal experience says that using fluride-free biomine toothpaste makes my tooth highly sensitive than using a good ol' Colgate. Now, I use it only twice or thrice per month randomly.
[flagged]
Whether this is true or not, it's absolutely not why they banned it.
They banned it as part of the culture war. That's 100% of the reason. "The libs" want it, so it must be banned.