5 ms·

What is the scientific evidence against water fluoridation?

Eumenes 2y ago
https://apnews.com/article/fluoride-water-brain-neurology-iq-0a671d2de3b386947e2bd5a661f437a5 https://apnews.com/article/fluoride-water-brain-neurology-iq...
woodruffw 2y ago
There's decent evidence that excessive fluoridation can cause developmental issues. Most advocacy around decreasing or eliminating water fluoridation comes from incorrectly extending that to the levels that are present in municipally fluoridated water, which are typically half or less than half of the generally recognized safe level. (A good proxy for this stuff is asking anti-fluoridation advocates whether they eschew green/black tea or defluoridate their groundwater. If they don't do either, then they're almost certainly in the "precious bodily fluids" crank camp.)
- lo_zamoyski 2y ago
  > (A good proxy for this stuff is asking anti-fluoridation advocates whether they eschew green/black tea or defluoridate their groundwater. If they don't do either, then they're almost certainly in the "precious bodily fluids" crank camp.) Could be, but not necessarily. It depends on the justification given. You can choose to drink green/black tea or not, but you can't really choose where you have fluoride in your tap water, at least not practically.
  - woodruffw 2y ago
    That's why I included groundwater defluoridation as a criterion. But that's also why it's a proxy, not a surefire way to determine someone's crank status. I'm sympathetic to the consent argument, on principle. But in practice people seem to have no objection to the government eliminating other degrees of choice, like drunk driving or sending your unvaccinated kids to school. So claims that municipal fluoridation at safe levels is a unique violation of consent comes across as special pleading.
    - rootusrootus 2y ago
      To be fair, drunk driving and unvaccinated kids both have quantifiable risks to innocent bystanders. Are those really comparable to dental caries? They are not contagious.
      - woodruffw 2y ago
        There's a quantifiable economic risk: a society that has to spend more on addressing caries has less to spend on education, libraries, hospitals, defense, etc. (This justification is also not novel to fluoridation: compare smoking in public places, where indirect secondhand smoke is unlikely to cause any health issues for bystanders but is still rationalizable in terms of social benefit.)
        rootusrootus 2y ago
        The economic argument opens the door to a lot more invasive interventions. Why not add semaglutide? It is likely that obesity costs significantly more to society than caries. I do not like the smoking example much, either. Even if difficult to quantify, making other people breathe your smoke is obviously different than something where the consequences are guaranteed to be 100% your own (aside from the aforementioned economic argument).
        woodruffw 2y ago
        For one, because we haven't done as much research on the long-term effects of semaglutide, especially on demographics it isn't current prescribed to. Fluoride, on the other hand, is well-researched. I think there's a larger argument about invasiveness being something that we can also quantify, and intervening on obesity is more invasive than intervening on caries, as you've noted. But the research argument above is perfectly sufficient on its own. If you don't like the smoking argument, consider enrichment/enforcement of foods (including public school foods). Iodized salt, enriched flour, fortified milk, etc.
- gojomo 2y ago
  Taking assurance from the fact that municipal-flouridation goes to "half or less" some "generally recognized safe level" implies that a low-concentration is enough for safety – "ensure your water's at that level, then have as much as you want!" – but that doesn't seem to be true. It's total consumption that brings risks. Someone who drinks twice as much water at that presumed "safe" level is at more danger – as are those who might be getting extra flouride elsewhere, such as from higher tea consumption or excessive use of flouridated toothpastes. Pre-2015, US flouridation standards used to be higher in colder climates, and lower in hotter climates, to account for the added water consumption in hotter climates. As of 2015, they guided everywhere to the originally-only-for-hotter-areas lower level, 0.7 mg/L, which is about half the levels with the decent evidence of harm. But that could still be putting high-total-consumption people at unnecessary risk, and for a pretty-small benefit (fewer cavities) that can be obtained with non-ingesting tooth surface flouride exposure (as with toothpaste). Any anti-flouridation advocate who relies on "their groundwater" rather than municipal taps probably does care about its natural concentration levels, and would only have to be concerned with moderate tea drinking if they're also receiving extra surprise flouride via municipal water. (A authentic concern for minimizing total consumption doesn't make any particular neurotic avoidance a good litmus test.)
  - woodruffw 2y ago
    > It's total consumption that brings risks. Someone who drinks twice as much water at that presumed "safe" level is at more danger – as are those who might be getting extra flouride elsewhere, such as from higher tea consumption or excessive use of flouridated toothpastes. The safe levels are built around a model of the amount of water a human being can consume, both directly (drinking tap water) and indirectly (cooking, drinks made with tap water, etc.). > for a pretty-small benefit (fewer cavities) that can be obtained with non-ingesting tooth surface exposure (as with toothpaste). This pretty drastically understates the public health impact of fluoridation, and overstates how likely people are to apply elective equivalents (e.g. sufficient fluoridated toothpaste). The good news is that we have concrete numbers for these impacts[1], which consistently show that even developed areas show significant dental health improvements with municipal fluoridation. [1]: https://www.researchgate.net/publication/335773400_Affirmation_Fluoridated_Water_Reduces_Caries_in_Children https://www.researchgate.net/publication/335773400_Affirmati...
coldpie 2y ago
There really isn't any. > What the current data shows is that there is a potential of neurotoxicity from fluoride at high levels, significantly higher than in the drinking water. But the same data shows, if anything, the managed drinking water levels are safe. Further, the best quality evidence does not show any clinical effect. https://sciencebasedmedicine.org/fluoride-and-iq/ https://sciencebasedmedicine.org/fluoride-and-iq/
- ericmcer 2y ago
  This seems to happen a lot though: some chemical/substance/whatever with benefits is discovered. Substance has negative effects on people. They test it until they find that those negative effects are no longer detectable at a certain low quantity. It gets rolled out and everyone starts putting it in their bodies. That seems like... I dunno not the safest way to do things?
  - coldpie 2y ago
    Indeed it would be bad if studies were done that way. Luckily they aren't (at least, not in mainstream health research, in the first world, in many decades). Medical ethics is a whole field, and public health in particular is really heavily scrutinized.
ericmcer 2y ago
I don't know but it doesn't pass my smell test. The rest of the world does not fluoridate their water (they would not have a financial incentive to), but we do and there are major financial incentives for us. If its only purpose is to reduce cavities, that doesn't seem worth it to me. There are better ways then dumping a chemical to the water supply...
- outworlder 2y ago
  There are developing countries that add fluoride to their water supply. Do they all have the same financial incentives? > There are better ways then dumping a chemical to the water supply... Fluoride is present in many naturally occurring water sources. Dental health is extremely important. If everyone had access to dental health care at least twice a year, then they could get all their fluoridation at the office. But that's not the case.
- namaria 2y ago
  > The rest of the world does not fluoridate their water Several countries do, in fact, fluoridate their water: https://en.wikipedia.org/wiki/Water_fluoridation_by_country https://en.wikipedia.org/wiki/Water_fluoridation_by_country
cryptonector 2y ago
What is the scientific evidence for water fluoridation?

https://apnews.com/article/fluoride-water-brain-neurology-iq-0a671d2de3b386947e2bd5a661f437a5 https://apnews.com/article/fluoride-water-brain-neurology-iq...

woodruffw 2y ago

There's decent evidence that excessive fluoridation can cause developmental issues. Most advocacy around decreasing or eliminating water fluoridation comes from incorrectly extending that to the levels that are present in municipally fluoridated water, which are typically half or less than half of the generally recognized safe level. (A good proxy for this stuff is asking anti-fluoridation advocates whether they eschew green/black tea or defluoridate their groundwater. If they don't do either, then they're almost certainly in the "precious bodily fluids" crank camp.)

lo_zamoyski 2y ago
> (A good proxy for this stuff is asking anti-fluoridation advocates whether they eschew green/black tea or defluoridate their groundwater. If they don't do either, then they're almost certainly in the "precious bodily fluids" crank camp.) Could be, but not necessarily. It depends on the justification given. You can choose to drink green/black tea or not, but you can't really choose where you have fluoride in your tap water, at least not practically.
- woodruffw 2y ago
  That's why I included groundwater defluoridation as a criterion. But that's also why it's a proxy, not a surefire way to determine someone's crank status. I'm sympathetic to the consent argument, on principle. But in practice people seem to have no objection to the government eliminating other degrees of choice, like drunk driving or sending your unvaccinated kids to school. So claims that municipal fluoridation at safe levels is a unique violation of consent comes across as special pleading.
  - rootusrootus 2y ago
    To be fair, drunk driving and unvaccinated kids both have quantifiable risks to innocent bystanders. Are those really comparable to dental caries? They are not contagious.
    - woodruffw 2y ago
      There's a quantifiable economic risk: a society that has to spend more on addressing caries has less to spend on education, libraries, hospitals, defense, etc. (This justification is also not novel to fluoridation: compare smoking in public places, where indirect secondhand smoke is unlikely to cause any health issues for bystanders but is still rationalizable in terms of social benefit.)
      - rootusrootus 2y ago
        The economic argument opens the door to a lot more invasive interventions. Why not add semaglutide? It is likely that obesity costs significantly more to society than caries. I do not like the smoking example much, either. Even if difficult to quantify, making other people breathe your smoke is obviously different than something where the consequences are guaranteed to be 100% your own (aside from the aforementioned economic argument).
        woodruffw 2y ago
        For one, because we haven't done as much research on the long-term effects of semaglutide, especially on demographics it isn't current prescribed to. Fluoride, on the other hand, is well-researched. I think there's a larger argument about invasiveness being something that we can also quantify, and intervening on obesity is more invasive than intervening on caries, as you've noted. But the research argument above is perfectly sufficient on its own. If you don't like the smoking argument, consider enrichment/enforcement of foods (including public school foods). Iodized salt, enriched flour, fortified milk, etc.
gojomo 2y ago
Taking assurance from the fact that municipal-flouridation goes to "half or less" some "generally recognized safe level" implies that a low-concentration is enough for safety – "ensure your water's at that level, then have as much as you want!" – but that doesn't seem to be true. It's total consumption that brings risks. Someone who drinks twice as much water at that presumed "safe" level is at more danger – as are those who might be getting extra flouride elsewhere, such as from higher tea consumption or excessive use of flouridated toothpastes. Pre-2015, US flouridation standards used to be higher in colder climates, and lower in hotter climates, to account for the added water consumption in hotter climates. As of 2015, they guided everywhere to the originally-only-for-hotter-areas lower level, 0.7 mg/L, which is about half the levels with the decent evidence of harm. But that could still be putting high-total-consumption people at unnecessary risk, and for a pretty-small benefit (fewer cavities) that can be obtained with non-ingesting tooth surface flouride exposure (as with toothpaste). Any anti-flouridation advocate who relies on "their groundwater" rather than municipal taps probably does care about its natural concentration levels, and would only have to be concerned with moderate tea drinking if they're also receiving extra surprise flouride via municipal water. (A authentic concern for minimizing total consumption doesn't make any particular neurotic avoidance a good litmus test.)
- woodruffw 2y ago
  > It's total consumption that brings risks. Someone who drinks twice as much water at that presumed "safe" level is at more danger – as are those who might be getting extra flouride elsewhere, such as from higher tea consumption or excessive use of flouridated toothpastes. The safe levels are built around a model of the amount of water a human being can consume, both directly (drinking tap water) and indirectly (cooking, drinks made with tap water, etc.). > for a pretty-small benefit (fewer cavities) that can be obtained with non-ingesting tooth surface exposure (as with toothpaste). This pretty drastically understates the public health impact of fluoridation, and overstates how likely people are to apply elective equivalents (e.g. sufficient fluoridated toothpaste). The good news is that we have concrete numbers for these impacts[1], which consistently show that even developed areas show significant dental health improvements with municipal fluoridation. [1]: https://www.researchgate.net/publication/335773400_Affirmation_Fluoridated_Water_Reduces_Caries_in_Children https://www.researchgate.net/publication/335773400_Affirmati...

coldpie 2y ago

There really isn't any. > What the current data shows is that there is a potential of neurotoxicity from fluoride at high levels, significantly higher than in the drinking water. But the same data shows, if anything, the managed drinking water levels are safe. Further, the best quality evidence does not show any clinical effect. https://sciencebasedmedicine.org/fluoride-and-iq/ https://sciencebasedmedicine.org/fluoride-and-iq/

ericmcer 2y ago
This seems to happen a lot though: some chemical/substance/whatever with benefits is discovered. Substance has negative effects on people. They test it until they find that those negative effects are no longer detectable at a certain low quantity. It gets rolled out and everyone starts putting it in their bodies. That seems like... I dunno not the safest way to do things?
- coldpie 2y ago
  Indeed it would be bad if studies were done that way. Luckily they aren't (at least, not in mainstream health research, in the first world, in many decades). Medical ethics is a whole field, and public health in particular is really heavily scrutinized.

ericmcer 2y ago

I don't know but it doesn't pass my smell test. The rest of the world does not fluoridate their water (they would not have a financial incentive to), but we do and there are major financial incentives for us. If its only purpose is to reduce cavities, that doesn't seem worth it to me. There are better ways then dumping a chemical to the water supply...

outworlder 2y ago
There are developing countries that add fluoride to their water supply. Do they all have the same financial incentives? > There are better ways then dumping a chemical to the water supply... Fluoride is present in many naturally occurring water sources. Dental health is extremely important. If everyone had access to dental health care at least twice a year, then they could get all their fluoridation at the office. But that's not the case.
namaria 2y ago
> The rest of the world does not fluoridate their water Several countries do, in fact, fluoridate their water: https://en.wikipedia.org/wiki/Water_fluoridation_by_country https://en.wikipedia.org/wiki/Water_fluoridation_by_country

cryptonector 2y ago

What is the scientific evidence for water fluoridation?