Some Data on Fluoride
David Gorski wrote yesterday about the threat that a second Trump term holds for American health, specifically if he keeps his promise to give RFK Jr. some high level position over public health. Unfortunately, we have seen this movie before, although the sequel promises to be much worse. Putting a pseudoscientist, crank, conspiracy theorist, anti-vaxxer in charge of the organizations that are supposed to use scientific evidence to protect public health is horrifying to contemplate.
During the COVID pandemic we at SBM found ourselves spending much of our time addressing the tsunami of misinformation that was coming out of the White House. We will likely have our work cut out for us over the next four years and beyond. Since RFK Jr specifically stated one of his top priorities is to get local governments to remove fluoride from public water supplies, let’s start there.
Fluoride has been added to some public water systems since 1945, starting in Grand Rapids MI. Fluoride is naturally occurring in many water systems to various concentrations, and it was observed that locations with high fluoride levels had better oral health and fewer cavities. Adding small amounts of fluoride to water supplies that lack it has been, according to the CDC, one of the 10 greatest public health measures of all time.
The bottom line is that fluoridation works. It is cost effective, saving from $20 to $38 in oral health care for every $1 spent. It is especially important for lower income areas who may lack adequate dental care. Tooth disease also correlates with a number of other serious systemic diseases. Communities that stop water fluoridation consistently see subsequent rises in oral disease and cavities, especially among the poor.
The benefits of fluoridation are actually not controversial. They are very clear. Anti-fluoridation activists, like RFK Jr., focus on the alleged toxicity. He wrote recently:
“Fluoride is an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease.”
He gives away his conspiratorial mindset by repeating the anti-fluoride fear-mongering that fluoride is an industrial waste. This is mostly a myth and in any case is irrelevant. First, fluoride exists is many water supplies naturally, at about the optimal levels for safe oral health. In the ocean fluoride is present at about 1 part per million. Most of this comes from leaching from rocks and minerals that contain fluoride compounds.
Added fluoride comes in three main forms, sodium fluoride, hydrofluorosilicic acid (hexafluorosilicic acid) and sodium silicofluoride. These come from a variety of sources, including some from industrial processes. But the source does not matter at all – regardless of the original chemical, all types completely break down in water resulting in fluoride ions. Fluoride is an element, and a fluoride ion is a fluoride ion, regardless of its source. Trying to scare people by calling it “industrial waste” is anti-science and just playing on chemophobia.
In the US the EPA has set a maximum fluoride level in public drinking water (regardless of source) at 4.0 mg/L. The CDC recommends an optimal level of 0.7 mg/L for oral health (again, less than the concentration in the ocean and many natural water supplies). As we all know, toxicity is all about dose. So are there health risk at fluoridated levels? No.
Let’s start with bone health. Multiple reviews have found that at levels of fluoride added to water systems, there is no association with bone fractures or negative effects on bone health. A National Resource Council review found mixed evidence for a possible increase in bone fractures starting at 4.0 mg/L. For this reason the CDC recommends lowering the highest allowable amount and the EPA is reviewing their standards.
But keep in mind, in the US we only add fluoride up to 0.7 mg/L. The higher concentrations were studied because there are locations with high naturally occurring fluoride levels in the US. The question is—when do we remove fluoride from drinking water? This is not about adding fluoride, which is well below any safety concern.
What about bone cancer? There was a single study in 1990 that found possible evidence of increased osteosarcoma in male rats (but not female rats, or mice) associated with higher levels of fluoride exposure. This looks like a typical quirky result. Subsequent studies did not find this, and epidemiological studies have not found any association with increased bone cancer and fluoridation programs.
Of course, you can always cherry-pick one study from over 30 years ago and ignore more recent and relevant data. This is also another hazard vs. risk issue. Toxicology studies generally overcall toxic effects—they are often designed to find toxic effects. But that does not tell us much about actual risk. For that, we need epidemiological data in humans, which in this case is negative.
I already wrote about fluoride and IQ. The quick summary is that in the studies touted by anti-fluoride activists that show a correlation with fluoride and lower IQ, they compared naturally high levels of fluoride (typically over 4 mg/L) to lower levels (in the range of fluoridation programs, 0.7 – 1.0 mg/L). So in the very studies cited, the fluoridation programs were associated with the higher IQ. Again, there is no evidence that fluoridation at levels deliberately added to public water carries any health risk.
But of course, as new data comes in we may tweak the guidelines to optimize benefit and minimize risk. The current recommendations, however, are based on the best current evidence available.
RFK Jr.’s recommendations are not based on the best science available. They are based on conspiracy theories, pseudoscience, and fearmongering. I guess that is what we can expect from the next four years. Buckle up.
