Flouride-alright-alright!

A Science-Minded Progressive’s Guide to the Fluoride Debate

Science journalist’s Sadie Dingfelder’s writing has appeared in National Geographic, the Washington Post, and Washingtonian magazine. She is the author of Do I Know You? A Faceblind Reporter's Journey Into the Science of Sight, Memory, and Imagination. She appears on The Gist to discuss science-based claims int he recurring segment “Is That Bullshit”.

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Like many sane people, I am not a big fan of RFK Jr. So when Mike Pesca of The Gist asked me to investigate whether there’s cause for concern when it comes to fluoride being added to drinking water, I thought the answer was an obvious and resounding “no.” After all, we have been adding fluoride to water since the 1950s. If it had adverse effects, surely we’d know about it by now, right?

Matthew McConaughey reportedly brushes his teeth five times each day

After reading a book on the topic as well as way too many journal articles and government reports, I am no longer so sure.

As a lone science journalist, I generally hesitate to weigh in on contentious issues. However, my assessment is in agreement with a recent analysis by the National Institutes of Health, a Cochrane Report, and one California circuit court judge. So, I don’t think I’m sticking my neck out when I say that consuming fluoride might not be so great for us after all.

Back when Americans Trusted the Government…

To understand what’s changed, let’s rewind to the 1900s, when a dentist named Fred McKay wanted to figure out why people in Colorado Springs had mottled brown teeth -- a condition known as Colorado Brown Stain. By 1931, McKay, in collaboration with scientists, figured out that the culprit was fluoride. The element, which naturally occurs in certain kinds of rocks, was leaching into the town’s water supply at high concentrations, ranging from 2 to 13 ppm (parts per million).

McKay also noticed that Colorado Brown Stain has a weird upside: It makes your teeth virtually impervious to cavities.

By looking at other towns with naturally fluoridated water, scientists determined that you could get the cavity-fighting benefits of fluoride without the brown-teeth side effect by titrating the concentration to 1 ppm.

This piqued the interest of government officials, because -- thanks to the advent of cheap refined sugar -- cavities were quickly becoming a major problem in America. In 1940, 10% of potential Army recruits did not meet the minimum requirement of having twelve teeth. Gap-toothed smiles weren’t just a public health problem, they were an issue of national security.

What to do? The government could have taxed sugar, or encouraged us to start brushing our teeth. But the increasingly powerful sugar lobby wasn’t a fan of the former, and the latter was deemed impractical. Fluoride seemed like the way to go.

The first experiment in municipal water fluoridation began on January 25, 1945 in Grand Rapids, Michigan. The city government started adding fluoride -- 1 ppm (part per million) -- to the community’s water supply. Over the next three years, scientists counted cavities in the mouths of the city’s schoolchildren, and they found a 60% reduction in cavities as compared to the control group, in nearby Muskogee.

Dazed, Confused, and Cavity-Free

The Mystery of Reduced Cavities

Since the advent of fluoride, tooth decay has declined precipitously. Seems like a public health slam-dunk, right? That’s what everyone thought, until someone noticed that cavities were going down just as much in places without fluoridated water.

What happened? Likely culprits include: An increase in teeth brushing, the increasing use of antibiotics, better diets and a ‘halo’ effect whereby fluoridated water reaches unfluoridated places via agriculture. However, the biggest part of the effect seems to be the advent of fluoridated toothpaste and mouthwash -- starting in 1955, with Crest.

The effectiveness of fluoridated toothpaste surprised scientists. In 1945, they thought that children had to ingest fluoride for it to be incorporated into their developing teeth. However, it quickly became clear that fluoride works topically, which means that if we swish it around and spit it out, we can get its benefits without its (potential) harm.

That’s part of the reason why fluoridated water never took off worldwide. Today, countries like Germany, the Netherlands and Sweden do not fluoridate their water. Instead, they keep their citizens’ grinning through other means, like universal health care.

This is Your Brain on Fluoride

Fluoride upgrades your tooth enamel by swapping out a hydroxide (OH⁻) molecule in the mineral structure of enamel with a fluoride (F⁻) molecule. This process converts hydroxyapatite, the natural mineral in enamel, into fluorapatite. Fluorapatite is harder and less soluble in acidic environments, making teeth more resistant to decay.

When you ingest fluoride, it also affects your bones, but not in a good way. People who live in places where naturally-occurring fluoride in the water reaches concentrations of 4 ppm or higher often suffer from a crippling disease known as skeletal fluorosis. Skeletal fluorosis results in bones that are dense, brittle and prone to fractures. In severe cases, it can significantly impair your mobility and quality of life.

The reason we know this is because naturally occurring, toxic levels of fluoride are a major problem in parts of China and India, as well as a handful of places in the United States, such as West Texas. In those communities, fluoride must be removed from the water to make it safe to drink. (Interestingly, the EPAmerely asks communities with more than 2 ppm of fluoride in the water to voluntarily report it, and they don’t start suing until the concentrations reach 4 ppm, which is probably way too high.)

The Big Question

Scientists agree that too much fluoride is bad for children’s brains and everyone’s bones. But what about small amounts of fluoride, on the order of the .7 ppm that is the current target for municipal water?

Unfortunately, we simply do not know.

On one hand, America’s been fluoridating its citizens for 80-ish years, and it hasn’t caused any apparent problems. Believe it or not, our IQs have been on the rise for most of the 20th century.

On the other hand, scientists have only just begun looking at adverse effects of low-levels of fluoride, and two recent studies found a link with lower IQs in children. One study of mother-child pairs in Mexico and an unrelated study in Canada both found that children’s exposure to even low levels of fluoride was associated with lower their IQ stores. These were both correlational studies that attempted to statistically correct for confounding factors like SES, so they are not definitive.

Still, if I were pregnant, I’d drink filtered, unfluoridated water, and I would use unfluoridated water in my baby’s formula. I’d also make sure my kids don’t eat fluoridated toothpaste, and to use only a pea-sized blob.

But that’s just me. You have to decide for yourself, and there’s not much evidence (yet) to help you make that decision.

Brushing off Past Progress

If we stop fluoridating water today, cavities will increase by 15-25%. That’s not the cataclysmic 60% increase predicted by some fluoride proponents, but it’s still a lot of cavities, and this will almost certainly affect poor people more than the rich.

However, we could easily make up for this by, oh I don’t know, providing universal dental health care. More modest measures, like mouthwash programs or after-lunch teeth brushing in schools, might also work.

This is all to say, the anti-fluoride folks are not (necessarily) off their rockers after all. It’s looking like municipal water fluoridation is not the healthiest way to reap fluoride’s benefits. If you live in a place that is voting to stop fluoridating the water, don't panic. One solid progressive response would be to advocate for something to take its place.

It seems that RFK Jr. might be right on this one. I’m as surprised as you are, but you know what they say: Even a stopped clock tells the right time twice a day.