Fluoride in your tap water is a good thing (in limited amounts, of course) | Photo: Steve Johnson, CC BY 2.0
I read in the news yesterday that the city of Moncton, New Brunswick (Canada, if you’re not familiar) is being urged to start fluoridation of its water supply now that five years have passed since it stopped doing so at the behest of a bunch of people who apparently have zero understanding of the words “scientific consensus” (exhibit A: the non-profit Canadians Opposed to Fluoride). According to the dentists in Moncton, the number of cases of dental cavities (aka caries or tooth decay) has risen since 2011, moreso among the city’s children.
People have opposed fluoridation of water supplies since it began, usually on the basis of the precautionary principle (“we don’t know for sure that it’s safe”) and of individual liberty (“it’s my right not to have it”). But in the decades and decades we’ve been doing this, we’ve had a lot of time to study it.
The scientific consensus is this: versus doing nothing at all, it lowers the number of cavities, especially in children and other at-risk groups, and has no substantial negative side effects at the recommended doses (in the US that’s 0.5-1.5mg/L, though an Australian review apparently picked a tighter band of 0.7-1.2mg/L — it’s based on temperature, which affects amount of water typically drunk, and other factors). In the words of Katherine Weno, the Director of the Division of Oral Health at the United States’ Centers for Disease Control,
“Expert panels consisting of scientists from the United States and other countries, with expertise in various health and scientific disciplines, have considered the available evidence in peer-reviewed literature and have not found convincing scientific evidence linking community water fluoridation with any potential adverse health effect or systemic disorder such as an increased risk for cancer, Down syndrome, heart disease, osteoporosis and bone fracture, immune disorders, low intelligence, renal disorders, Alzheimer disease, or allergic reactions.”
It’s safe, and it works.
Water usually comes with less than 0.5mg/L of fluoride in it from natural sources, so some ought to be added, but in some areas springs and wells can have water with up to 50mg/L of fluoride in it, in which case you’re going to want to de-fluoridate, because (say it with me) the dose makes the poison.
If you could reliably distribute fluoride rinses, and reliably get everybody (everybody) to use them properly, then you might find you don’t need systemic fluoridation. But in a world with poor people, non-universal dental care, children who suck at brushing their teeth, and other mitigating factors, water fluoridation is a safe and effective means of lowering the rate of tooth decay in the general population.
So if you’re listening, Moncton, the lesson is clear: get back to fluoridation. And if you need actual advice from a trained professional, check out the CDC’s Statement on the Evidence Supporting the Safety and Effectiveness of Community Water Fluoridation from last year. Or, you know, Health Canada’s website about it.
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Richard Ford Burley is a human, writer, and doctoral candidate at Boston College, as well as an editor at Ledger, the first academic journal devoted to Bitcoin and other cryptocurrencies. In his spare time he writes about science, skepticism, feminism, and futurism here at This Week In Tomorrow.