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Bill Chameides

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The Chemical Marketplace Series -- Drinking It In: Is Fluoride Good for You?

Posted: 09/14/2010 6:15 pm

Crossposted with www.thegreengrok.com.
More than 80,000 chemicals are produced and used in the United States. This is one of their stories.

With nearly 200 million Americans drinking fluoridated tap water these days, is it time to ask ourselves, do we really need the fluoridation?

Fluoridation and the Red Scare

I grew up in the 1950s when municipalities across the nation began fluoridating their drinking water to promote dental health. My parents thought it was a good idea and so, so did I. But I remember hearing friends say their parents were against it, some even claiming that fluoridation was a communist plot to undermine capitalism by poisoning our water supply.

drinking water and fluoridation - www.thegreengrok.com
The difficult case of fluoride. Time magazine lists it in its "Top 10 Common Household Toxins" and yet, starting with Grand Rapids, Michigan, in 1945, many U.S. municipalities have added it to drinking water.

(This communist myth was carried to extremes in Stanley Kubrick's 1964 classic black comedy Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb in which a mad general, Jack D. Ripper, played by Sterling Hayden, cites the fluoridation of water as a primary motive for a nuclear strike against the Soviet Union.)

While back then such a communist plot seemed pretty scary, now it just seems far-fetched. But today there are people, thoughtful people, who, despite decades of living with fluoridated tap water, oppose it. What's the fear now and is it grounded in reality? I decided to find out.

We Fluoridate Water in the Name of Healthy Teeth

We add fluoride [pdf], a reduced form of the naturally occurring fluorine, to water (which contains some amount of fluoride naturally) to prevent tooth decay. And while to you or me a cavity may seem little more than a hassle -- the sting of Novocain, the rrreenee-reenee of the dentist's drill, a drooping lip for a few hours -- it's a big deal from a general and public health point of view. Consider the following:

The Chemical Marketplace
A series that looks at chemicals in everyday consumer products
     BPAF »
     Fluoride
     PFOA »
     TDCPP »
     Triclosan »

So, if your job is protecting public health, fluoridating drinking water might seem like a very good idea. But it's only a good idea if it works. Does it?

Fluoridation Testimonials and Then the Fine Print

To find out, I first Googled the Centers for Disease Control (CDC) and the Surgeon General. Results?

But after heaping accolades on fluoridation in one paragraph, the Surgeon General waffles later on: "There are no randomized, double-blind, controlled trials of water fluoridation because its community-wide nature does not permit randomization of people to study and control groups. ... Conducting a study in which individuals are randomized to receive or not receive fluoridated water is unnecessary and is not feasible." Not feasible? Maybe. But unnecessary? I don't think so.

In 2000 the Centres for Review and Dissemination at the University of York in England similarly equivocated in a review of fluoridation research. While reporting [pdf] "a beneficial effect of water fluoridation," the researchers also note the data "could be biased" because of the potential for "confounding factors," and went on to state that: "Given the level of interest surrounding the issue of public water fluoridation, it is surprising to find that little high quality research has been undertaken." 

So, apparently the studies touting the benefits of fluoridation are not all that iron-clad. And then there are the studies that seem to show that fluoridation is plain out ineffective.

Studies Finding Fluoridation Ineffective

Several studies from Europe and elsewhere (see here [pdf], here and here) show that developed countries now have similar levels of cavities whether they fluoridated their water or not -- a change from the 1970s and '80s when countries that did not fluoridate their water had more tooth decay on average than those that did.

Today, according to these studies, the incidence of tooth decay is universally low regardless of fluoridation.

What's the Harm of Adding Fluoride to Drinking Water?

Fluorosis
People along Ethiopia's Ridge Valley are plagued with fluorosis because the groundwater they drink is heavily laced with geologic fluoride. Pictures taken in May 2010 by my Nicholas School colleague, Avner Vengosh, who studies the sources of groundwater contamination in the region.

The problem is fluorosis, dental and skeletal. Mild forms of dental fluorosis lead to faint discoloring or mottling of the tooth surface, a condition easily covered up by a dentist.

More severe fluorosis is characterized by dark stains and pitted teeth, in which the tooth's protective enamel is severely compromised. (See more pictures of fluorosis here.)

Skeletal fluorosis can be a lot more serious. In its mild form, skeletal fluorosis brings painful stiff joints; but in severe cases, individuals can experience crippling calcification and/or fusing of the vertebrae.

How Much Fluoride Is Too Much Fluoride

U.S. municipalities add between 0.7 to 1.2 parts per million (ppm) of fluoride to our drinking water. The U.S. Environmental Protection Agency's standard for safe drinking water is 4 ppm, well above the 1.2 ppm maximum from fluoridation. So all's well, right? Not quite:

  • In addition to being added to a lot of our drinking water, fluoride is in our foods, our soft drinks, and of course our toothpaste. In fact there's a lot more fluoride in the average American diet today than in 1962 when the standards were established. Depending on your diet, your drinking water's 0.7-1.2 ppm dose of fluoride may or may not be safe. For example, a recent study illustrated that babies fed food reconstituted with optimally fluoridated water would exceed the safe fluoride intake for infants.
  • In a 2006 report the U.S. National Academy of Sciences concluded that EPA's 4 ppm standard for fluoride in water is not sufficiently protective and should be lowered -- a recommendation that EPA has yet to respond to (see story) and one indicating that the margin of safety between the supposed beneficial levels of fluoridation and harmful levels leading to fluorosis is much narrower than current regulations imply.
  • And then there's the kicker -- the health risks of fluoridation may include cancer. For example, Elise Bassin of the Harvard School of Dental Medicine and colleagues found [pdf] that the incidence of osteosarcoma (a rare and deadly form of bone cancer) increased by a factor of about five to six for boys who drank moderately fluoridated water as compared to those who drank water with little to no fluoride (more on study). (Without minimizing this result, bear in mind that the chances of an adolescent boy contracting osteosarcoma is only about eight per one million boys per year. So, if correct, this study suggests that the risk increases to about 40 to 48 boys per million per year. Those are still pretty long odds, long enough to suggest that it might make sense to accept the increased but still minuscule cancer risk for the benefit of avoiding tooth decay -- that is, if fluoridation really protects you from tooth decay.)

So, What to Conclude About Fluoridating Water?

Fluoridation, controversial in the '50s, is still controversial today. Maybe fluoridation fights cavities, maybe not. Maybe it's safe, maybe not. But there's one more wrinkle.

When the U.S. policy to fluoridate our drinking water was first developed, scientists and dentists believed that only ingested fluoride benefited teeth. We now know that that's not true. Topical application (e.g., from brushing teeth with toothpaste) is also effective at reducing cavities, by about 24 percent on average, though it's not without its own risks. In the decades since 1955 when Crest with stannous fluoride first hit the market, it's become hard to find a toothpaste without fluoride. Do we need fluoridation if we've got fluoride toothpaste?

All this makes me wonder, could fluoridating drinking water now be as anachronistic as fears of a communist plot?

Additional Resources

  • Does your area fluoridate your water? Find out here or through your local water utility.
  • Does your water filter filter out fluoride? See if it's listed here or check with the company that makes your filter for information on what is filtered by your brand's.
 

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