The war on fluoride heats up

“It's not what you don't know that gets you in trouble. It's what you know for sure that just ain't so.”

- Mark Twain

In 1945 the US started adding fluoride to community water systems once the evidence became clear that low levels of fluoride in drinking water can play a significant role in reducing tooth decay. It was heralded as such a success that the CDC has since declared water fluoridation as one of the 10 great public health interventions of the 20th century. Still, water fluoridation has had its share of critics from the beginning.

Almost all water contains some naturally occurring fluoride, but usually at levels too low to prevent cavities. The recommended fluoride concentration in drinking water (also called the optimal level) is 0.7 milligrams of fluoride per liter of water (or 0.7 parts per million, or ppm). This is equal to about 3 drops in a 55-gallon barrel.

State and local governments decide whether to implement water fluoridation. Often, voters themselves make the decision to adjust water fluoride to improve public health. Some states have laws that require water systems of a certain size to provide fluoridated water. Community water systems add fluoride as needed to reach the optimal level. Communities also might remove fluoride if the natural level is too high. In some areas, the level of naturally occurring fluoride in water is already at a level proven to prevent cavities, and therefore no adjustments are necessary.

With a new administration soon coming into the White House, the issue of public water fluoridation is front and center again. Certain members of the incoming government have advocated for ending fluoridation practices, claiming “Fluoride is an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease.”

As a dentist, I feel compelled to respond to this statement. Each one of those claims is absolutely true. Fluoride is often sourced from industrial processes as a byproduct. This has simply proven to be the most cost-effective way of obtaining it. And fluoride in high doses has been shown to cause brittle bones, lower cognitive scores in children and adults, and a host of other disorders.

However, to be fair, some perspective is in order. For comparison, glycerin is a byproduct of biodiesel production (i.e. an industrial waste) and is used in cosmetics and pharmaceuticals, including soap, shampoo, toothpaste, lotion and shaving cream. In other words, everyone has used it at some point, with no ill effects. As for fluoride concentrations, the CDC recommendation of 0.7ppm has been shown to safely provide the anti-cavity benefit without any of the untoward side effects. In fact, no robust research has shown that fluoride consumed at 0.7 ppm is enough to cause any of the aforementioned maladies. The only level at which research has shown harmful effects is 1.5 ppm, twice the recommended dose, and only after extended periods of consumption.

Still, some communities feel that removing fluoride from their water supply is the right thing to do. In 2011, the city of Calgary, Alberta decided to stop water fluoridation. By comparison, nearby Edmonton continued to fluoridate its water. Of the approximately 2,600 second grade students in each city who took part in a recent study1, 55.1% of Edmonton participants had one or more cavities in their baby teeth while in Calgary 64.8% of children had one or more cavities. In addition, just eight years after fluoridation ended in 2011, the need for intravenous antibiotic therapy in children to avoid death by dental infection rose 700% at the Alberta Children’s Hospital in Calgary.

Diane Colley-Urquhart, one of the councilors who voted to stop adding fluoride to the water in 2011, says it’s a decision she says she now regrets. “I think one of the biggest lessons in my political life was the error I made to remove fluoride.” In 2021 the city of Calgary decided to reintroduce fluoride back into the city water supply, set to take place early in 2025.

The controversy over water fluoridation will likely never go away. Communities will experiment with stopping fluoridation from time to time, and many will eventually see the benefits far outweigh any perceived risks. Political leaders will give more weight to a handful of anecdotal reports than decades of robust research. Conspiracy theorists will claim it’s a communist plot. Science deniers will have books to sell and websites that need clicks. And all of them know for sure that fluoride is dangerous. The problem is it just ain’t so.

- Dr. McGann

1 https://link.springer.com/article/10.17269/s41997-024-00858-w