inFact with Brian Dunning inFact with Brian Dunning


All About Fluoridation

Is fluoridated water truly as poisonous as some activists make it out to be, or is that just a lot of unscientific hype?

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Fluoridation is practiced by many municipal water providers around the world. It's the management of fluoride levels in drinking water. Fluoride is a mineral that occurs naturally in all fruit, vegetables, and water supplies, usually at trace levels but sometimes very high. Thus, fluoridation means either adding or removing fluoride to bring the level to the ideal amount.

The ideal level is right around 1 milligram per liter, perhaps a bit less.

Too much fluoride causes a condition called fluorosis, which starts with mottling on the teeth, and at very high levels can cause deposits in the bones and even permanent disability by skeletal fluorosis. One village in India was found to have levels as high as 23 milligrams per liter. Some places like North Africa and much of the Western United States have natural levels at least twice what's recommended, so fluoridation is important here to bring it down to a safe level.

Too little fluoride leaves teeth open to decay and causes weakening of the skeleton. Most of the world has levels slightly lower than ideal, so fluoridation is usually desirable. There are only a lucky few places that naturally have just the right amount.

A number of conspiracy theorists have called fluoride a dangerous poison. Some say it's carcinogenic, some even say it's a neurotoxin that the government uses to keep the population stupid. None of this is true. Fluorosis is not a cancer and it doesn't make you dumb. There is plenty of reason to avoid high fluoride levels without making up nonsense.

Unfortunately, removing fluoride from water is hard to do and expensive, so usually we provide alternate sources of water for human consumption instead of trying to alter the natural supply.

It's easier to add fluoride in regions where the natural level is low enough that skeletal and dental weakness might result. Reduced tooth decay vs. the low cost of adding fluoride make it one of the best bangs for the buck anywhere.

But some anti-fluoride activists say that adding fluoride to water with too low a level amounts to forced medication by the government. This is true, and it's a perfectly valid ideological argument. But the argument stands on its own; it is unnecessary, dishonest, and logically wrong to make up bad science and untrue chemistry to bolster this argument.

— Brian Dunning

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References & Further Reading

Estupiñán-Day, Saskia. Promoting oral health: the use of salt fluoridation to prevent dental caries. Washington DC: Pan American Health Organization, 2005.

Griffin, SO, Jones, K, Tomar, SL. "An Economic Evaluation of Community Water Fluoridation." Journal of Public Heath Dentistry. 1 Mar. 2001, Volume 61, Number 2: 78-86.

Hem, John D. Study and Interpretation of the Chemical Characteristics of Natural Water. Washington DC: U.S. Government Printing Office, 2005. 120-123.

Langford, Cameron. "GOP Hosts County’s Public Health Officer for Fluoride Talk." Humboldt Advocate. 14 Jul. 2006, Newspaper: Unknown.

McKay, Frederick S. "Mass Control of Dental Caries Through the Use of Domestic Water Supplies Containing Fluorine." American Journal of Public Heath Nations Health. 1 Jun. 1948, Volume 38, Number 6: 828-832.

National Cancer Institute. "Fluoridated Water: Questions and Answers." National Cancer Institute - Comprehensive Cancer Information. National Institutes for Health, 29 Jun. 2005. Web. 12 Nov. 2009. <>

Nixon, Janice M., Carpenter, R. G. "Mortality in areas containing natural fluoride in their water supplies, taking account of socioenvironmental factors and water hardness." The Lancet. 2 Nov. 1974, Volume 304, Issue 78: 1068-1071.

WHO. Inadequate or Excess Fluoride: A Major Public Health Concern. Geneva: World Health Organization, 2010.


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