Angry Toxicologist

Seems appropriate since controversial topics like vaccines are on the agenda this week.

A study published in EHP finds that high fluoride (mean of 8.3 mg/L) or arsenic in water decreases IQ (it’s very rare to have a fluoride level this high in the US, artificial fluoridation is supposed to be 0.7-1.2 mg/L and usually is). This isn’t anything new really, it’s been published multiple times before, just not in a major English language journal (and a couple of the previous studies had some control issues – controlling for Arsenic for one). This comes on the heels of a couple other interesting things about fluoride:

1) A study of US children (seems to be the most rigorous so far on the topic) showing increases in osteosarcoma (a bone cancer) only in boys only if exposed to fluoridated drinking water during periods of fast bone growth. The males only finding is also found in an other epi study done in NJ and in rats – it’s curious, I can’t think of why this would be. Naturally boys are predisposed to osteosarcoma from looking at the incident rates. Any oncologists know the biological basis for this sex difference?

2) The National Research Council (part of the National Academies) saying the EPA’s MCL for fluoride in water is too high (The MCL is currently 4 mg/L; most systems that fluoridate are at ~1 mg/L) due to skeletal fluorosis, I believe (brittle but very dense bones – accompanied by bone pain if I’m not mistaken). As an interesting aside, fluoride was tried as a treatment for osteoporosis a while back (80s-90s) becuase of the more dense bones thing. Unfortunately, it only makes them dense, not stronger, in fact more brittle (a density scan will tell you that things are getting better but a look at the bones show that the osteoporatic structure has not been changed – there is still loss of connectivity). Epi studies of the relationship between hip fracture and fluoride are all over the place (positive, negative, or no association).

3) The American Dental Association recommended (based on some info in the NRC report) that baby formula not be made up with fluoridated water.

I find all this a lot more credible than any of the anti-vaccine stuff. The Bassin et al. study is particularly good. They went back and verified the water fluoride levels of the cases and controls at the times of their early childhood in the towns they lived in (children usually are diagnosed with osteosarcoma in their mid to late teens I believe). Can you imagine the work (and mind-numbing at that)? Whew, I’m glad that wasn’t my thesis project back in the day.


  1. #1 Greg Blumenthal
    July 26, 2007

    In looking at the EHP article, the IQ distribution in their control population seems less similar to the general Chinese population than the high fluoride group does. I’m not a statistician, so I’m not exactly sure of the best way to run that comparison. If the control population is not as representative as is portrayed in the text, the strength of their conclusions may be excessive.

  2. #2 JW
    July 26, 2007

    How important is it to use toothpaste without fluoride? Does it make much of a difference?

  3. #3 angrytoxicologist
    July 26, 2007

    While the IQ of the provence was different from the control, the IQ of the general Chinese population was no different from control. Any way you look at it though, the fluoride population was decreased compared to either the control group, the Shanxi provence, or the Chinese population as a whole. Therefore nothing fancy required. An AngryStatistician is free to correct me here.

    A possible explaination of the slight difference between “control” groups is that China has a lot of areas with serious fluoride and arsenic water contamination and since the “control” group was actually a low arsenic and low fluoride area, it makes sense that this area might have a higher IQ. There are also a lot of other explainations that I could gin up but since they don’t really affect the outcome, I’ll stop typing.

    Like the tube says, don’t swallow it. Also like the tube says, kids should use a pea-sized amount. If you think your kids are swallowing (many do, the average is something like 25% goes down the hatch with a pretty large standard deviation), you could use a non-fluoride toothpaste. For adults, I don’t see much of an issue.

  4. #4 Anna
    July 26, 2007

    After sitting on the fence for some time (ouch!), I have decided to come down on the side against fluoride for our family. Despite consuming lots of fluoridated water when growing up, twice yearly dental checkups, fluoride treatments and toothpaste, etc., I had plenty of cavities as late as into my 20s and so did my sisters (and we had a pretty wholesome diet of good homegrown and homecooked food, too). Now in my 40s, I am mildly hypothyroid, and there appears to be a possible link to fluoride and hypothyroidism. I just don’t find the evidence for fluoride very compelling and while the evidence against it isn’t conclusive, it seems prudent to err on the side of caution.

    My 8 yo son is growing up in an area of unfluoridated water and we stopped using fluoride products a few years ago. Instead we use toothpaste with enzymes and xylitol (very common formula in Europe but harder to find in the US) as well as 3X year dental cleanings instead of 2X. Despite my son’s really lax toothbrushing habits, he has had no cavities yet, but nearly all his friends have had numerous cavities and even crown restorations (as early as kindergarten!).

    Another aspect that may be helping to keep his teeth protected from within as well as from the exterior is low sugar and starch consumption. Additionally, we use high vitamin cod liver oil, butter from grassfed cows, and lots of homemade bone broth. We also use certified raw dairy products, which have the full complement of nutrients and enzymes in their natural form. I have no way of knowing if his diet in particular is protecting his teeth, but there is some historical evidence for it

  5. #5 Pygmy Loris
    July 26, 2007

    I’m surprised by the link between flouride and IQ, but it would take many studies to convince me that flouridated water is bad for children. Although people with flouride still get cavities, you’d be shocked at the incidence of cavities in populations without any flouride that eat our carbohydrate heavy, processed diets. Flourosis is obviously a serious problem in areas with heavy flouride concentrations, but the typical amount in most municipalities in the US is probably not a threat.

    You do need some ingested flouride for healthy dental development, but too much is obviously a bad thing.

    As for dental cavities, if you really want to prevent them start chewing really tough foods. Things like peanut shells and such. Cavities start to show up in the archaeological record at about the same time as more heavily processed foods (such as milled grains) and as dental wear decreases. Prior to the decrease in dental wear, your chewing surfaces wore away faster than cavities could form.


    If you really want to prevent cavities on the molars, I highly recommend sealants. They work extremely well and naturally wear away and the child ages.

  6. #6 nyscof
    July 26, 2007

    Actually, ingested fluoride only delivers risks without any benefits. According to the CDC, fluoride’s beneficial effects occur topically only. And the levels emerging in the saliva to bathe the teeth topicaly with fluoride are too low to have an effect.

    The following is from the CDC fluoride recommendations:

    Saliva is a major carrier of topical fluoride. The concentration of fluoride in ductal saliva, as it is secreted from salivary glands, is low — approximately 0.016 parts per million (ppm) in areas where drinking water is fluoridated and 0.006 ppm in nonfluoridated areas (27). This concentration of fluoride is not likely to affect cariogenic activity.

    According to the CDC, “[L]aboratory 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”

    The prevalence of dental caries in a population is not inversely related to the concentration of fluoride in enamel (37), and a higher concentration of enamel fluoride is not necessarily more efficacious in preventing dental caries (38).

    For more info

  7. #7 cooler
    July 26, 2007

    Yes , I spent some time looking for the original scientific paper that said toothpaste w/ fluoride was much more effective than ordinary toothpaste w/o flouride, does this paper exist?

    the lack of of original papers proving some things that everyone believes to be true is strange. Its like when nobel prize winner Kary Mullis Kept asking people for a reference for the statement “hiv causes aids” and no one could give it to him. Where are the original scientific papers from the 30’s that showed it was ok to take thimerosol?

    Im not saying these things are not true, about hiv/fluoride/thimerosols safety but you have to wonder the reason everyone beleives something has much less to do with science and a lot more to do with groupthink and thought control.

  8. #8 angrytoxicologist
    July 27, 2007

    Cooler, you hit upon a rather sensitive subject. The original trial is the Newburgh trial (1956 published in the Journal of the American Dental association). It has since been found to have many problems that largely make the trial invalid. More interesting about the history of that study was that many of the people involved with the study have some shady pasts (a lot of this was revealed in the 90s when a lot of DoD papers from the WWII period were released). A man largely behind it all Harold Hodge (generally considered the dean of toxicology in the US) was working with the Manhattan project to keep it going. A big problem with producing all the aluminum and the uranium that was needed for the war and the manhattan project was that it produced massive amounts of fluoride contamination. The first problems were in NJ where the peach crops starting dying and then the cows got crippled. The farmers starting getting sick and it turned out they had blood F levels about 31X what the average person has. They waited till the war was over (for patriotic reasons? I’m not sure), then they sued DuPont and the Manhattan project for the pollution. One of main things that they used as evidence was the mottling of their teeth (fluorosis). Hodge was dispatched by the Manhattan project to take care of it. He concluded that the mottleing could be due to natural fluoride in the water and therefore the farmers couldn’t say it was the war project. The FDA was about to ban food from NJ due to high fluoride content and DuPont and the DoD were very worried about the public realations problem this would cause (A manhattan project captian talked to the FDA food guy and nothing was banned). Not wrongly worried either, their ability to produce uranium would have been severly hampered if they had to make sure they weren’t spewing HF in the air (judge this how ever you like but during war time many decisions are made that may have seemed like good risk/benefit ratios that no longer applied once the war is over but it was too hard to back out and say this is no longer right). Hodge wrote a Colonel in the program “Would there be any use in making attempts to counter act the fear of fluoride…through lectures on F toxicology and perhaps the usefulness of F in tooth heath?” This is darkly funny in a way since one of they main complaints was tooth mottleing (still under debate as to whether this can be called an ‘adverse’ effect; the NRC does not consider it to be adverse, only cosmetic).

    The conference that thought up the study was supported by Manhattan Project (secretly at the time) money and concieved to see if there were non-dental health effects with the exposure to fluoride (participants were not told of the purpose). It has been suggested that they also censored the data but it’s hard to find out because a 1994 presidental commission couldn’t get the secret cold war documents (I know, crazy, huh?). Also interestingly, one of the Drs (Joe Howland) that drew the blood from the Rochester residents was a chief of Manhattan Project investigations for information on the health effects of bomb project materials. He had dosed at least one person with plutonium to see the effects (the guy was chosen at random in a Oak Ridge hospital – he had gotten in a car accident that landed him in the hospital and wasn’t told what was being done to him). This human experimentation also came out in the 90s papers.

    Not that this says much about the science of the safety of fluoride but it does leave an awful bad taste in ones mouth.

    How did Hodge get the idea to talk about the good effects of F on teeth? In 1948 a paper performed by the Manhattan project at the suggestion of Hodge was published in the Journal of the American Dental Association showing that workers who worked with fluoride had less cavaties. Original versions of the studies were found in the files of the Manhattan Project’s Medical Section concluded that fluoride did not prevent cavaties and in addition the “teeth seemed to be deteriorating”. A second study on workers in Cleveland (where two workers had died due to fluoride and the pollution was so bad the FBI was called in) was the one published. A look at the secret version shows how the paper could say there were less caries; the men exposed to fluoride hardly had any teeth. Almost sad enough to be funny.

  9. #9 cooler
    July 27, 2007

    very interesting

  10. #10 Anna
    July 28, 2007

    Pygmy Loris,

    Thanks for your comment to my comment. I can see by your online name that you probably know a lot more about primate teeth than I, so I did a few minutes of googling to learn a bit more about how teeth wear down with various historical diets, etc. I have read much of the Weston A Price, D.D.S. book, Nutrition and Degeneration but I also found this site informative and pertinent to your comment on dental wear: Chewing hard foods like peanut shells seems to strengthen the jaw bone and muscles.

    The way it appears to me, the wear on teeth from a paleolithic hunter-gather diet would have been slow (and primarily in the front teeth due to tooth-on-tooth contact?), but matched to the slow, limited rate of caries development (due to the limited amount of sugar and starch consumption). But high rates of dental wear from stone-ground grains (containing fine, abrasive sand) would not have been sufficient to wear away the fast rate of caries progression in later societies (due the acid-producing bacteria that develop with higher carbohydrate consumption).

    Regarding sealants for cavity prevention in molars, I don’t doubt they protect against cavities on molars (which is a prime concern for children), but my understanding is that polycarbonate plastics are used for the sealants. And there is some recent concern that polycarbonate plastics leach bisphenol-A (BPA), which is an endocrine disrupter. I’m not sure how conclusive all that is at this point, but again, for now, I am choosing to err on the side of caution.

    The more I look into this, the more it convinces me that the less sugar and starch we eat, the better, and for more than just healthy teeth. And modern fixes to compensate for a bad diet aren’t necessarily the solution. I wouldn’t say our family’s diet is paleolithic, but it is getting to be a rather close modern approximation. So far, it appears to suit us in more ways than one.

  11. #11 Phil Boncer
    July 29, 2007

    I do not have a strong opinion on the relative benefits vs. risks of fluoridation for any given individual. From what I can tell, low fluoride doses do seem to have an overall benefit due to the probable dental health benefits. Accordingly, I use a fluoridated toothpaste (my area does not fluoridate the water).

    However! I see two arguments that I believe make a good case against fluoridation of water, and neither of which I see brought up in the discussion very often.

    1) Potential environmental issues — We are increasingly concerned with what sorts of chemicals we are releasing into our environment (intentionally or not), and how those affect all life forms, not just humans. Excreted drugs, leachables from plastics, electronics, and other waste, etc. It seems unwise to me to then be intentionally flooding the environment with fluoride compounds so that some small percentage of it will be consumed by humans. Even if it can be shown conclusively that fluoride is beneficial to human health, it does not then follow that it is beneficial to fish and frogs and ducks and so on. It thus seems like a *much* better practice to then dose humans directly when appropriate, where you can control the dose and you can limit the pollution.

    2) Individual rights — Tooth decay is not a disease that can cause the sort of epidemic that public health is legitimately concerned with. Your risk of it is not defined by the fluoridation status of your friends and neighbors. Therefore, it is not a disease that it is appropriate to bring the force of law (or other force) to bear upon. Each person should be free to decide for himself whether he wishes to be fluoridated, and to then do so if he wishes, or not if he doesn’t. Even if the decision of the individual can be shown to be rationally erroneous, he has the right to make his own decisions on any matter that does not adversely affect the health and safety of others.


  12. #12 Qalmlea
    August 5, 2007

    I have concluded that, for me, fluoridated water is a good thing. A year ago my mom got a reverse osmosis water filter. I started filling water bottles there and bringing them home. Both our teeth have deteriorated significantly since then. Admittedly, bad teeth seem to run in my family. My grandma had hers pulled when she was in her 30s because they were essentially rotten. At any rate, that convinced me to install a lesser water filter at my house, one that leaves the fluoride intact. I don’t know, though, how the benefit/risk ratio might go for people without a family history of bad teeth.

    What about the claim made by dental products that the presence of fluoride can help a tooth “heal” minor cavities? Are there any studies to back that up?

  13. #13 Phil Boncer
    August 6, 2007

    I think there isn’t really much debate about whether fluoride is good for your teeth. It almost certainly is, which is why, as I indicated, I use a fluoridated toothpaste. But if you need/want fluoride for your teeth, you can use do the same, or get your dentist to give you fluoride treatments. Doing it through the water supply is wasteful and inefficient, delivers an uncontrolled dose, is a violation of the rights of those who don’t want to be dosed, and is not environmentally responsible. Those are the problems that make the practice a poor way to deliver the goods.


  14. #14 Nantwich dentist
    May 22, 2009

    More Fluoride content in drinking water or toothpaste is may damage the teeth enamel and thus dental and oral health is affected.

  15. #15 Dentist North York
    June 26, 2009

    Fluoride is good for your teeth in low concentrations. If makes teeth more resistant to acidic breakdown by cavity causing bacteria.

  16. #16 Invisalign Vaughan
    June 26, 2009

    If fluoride is swallowed in the form of toothpaste as a child, it can lead to fluorosis, which affects the development of the adult teeth resulting in brown spotting.

  17. #17 söve
    July 1, 2009

    Delays and denials söve are not cost free. I’ve seen more than one analysis that concludes that söve the FDA is likely to have söve cost more lives through the time it takes to approve a good medicine söve than it has saved from disaprroving bad ones.

  18. Fluoride in the water has resulted in a large decrease in cavities. Back when water was not fluoridated, cavities were much more common problem.

  19. #19 kameralı sohbet
    August 3, 2009

    Delays and denials söve are not cost free. I’ve seen more than one analysis that concludes that söve the FDA is likely to have söve cost more lives through the time it takes to approve a good medicine söve than it has saved from disaprroving bad ones.

  20. #20 Dental Implants
    September 30, 2009

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  21. #21 Chat odaları
    October 20, 2009

    I’ve seen more than one analysis that concludes that söve the FDA is likely to have söve cost more lives through the time it takes to approve a good medicine söve than it has saved from disaprroving bad ones

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  23. #23 komik videolar
    November 20, 2009

    More Fluoride content in drinking water or toothpaste is may damage the teeth enamel and thus dental and oral health is affected.

  24. #24 Abercrombie
    November 30, 2009

    I use a fluoridated toothpaste. But if you need/want fluoride for your teeth, you can use do the same, or get your dentist to give you fluoride treatments. Doing it through the water supply is wasteful and inefficient, delivers an uncontrolled dose, is a violation of the rights of those who don’t want to be dosed, and is not environmentally responsible. Those are the problems that make the practice a poor way to deliver the goods.

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