The Tooth of the Matter

A new call to put fluoride in the city's water raises old fears.

After 54 years of opposition, the City of Portland is moving to put fluoride in your drinking water.

Upstream Public Health, the group behind the fluoridation move, launched what amounted to a political sneak attack, quietly building support at City Hall for months. Eight days after news leaked about the group's plan, a majority of the City Council—Mayor Sam Adams and Commissioners Randy Leonard and Nick Fish—said they'd vote to fluoridate Portland's water.

The developments have set the Internet buzzing with howls of complaint from a small but extraordinarily loud and persistent group of fluoridation opponents who say they haven't been given a chance to engage in the public debate.

To be sure, anti-fluoridation activists have always raised a voice from society's fringes. In the 1960s, members of the John Birch Society claimed fluoridation was a Communist plot.

Fluoridation proponents cite decades of studies showing fluoridation is a safe way to improve dental health. The Centers for Disease Control call it one of the 20th century's great public health achievements, up there with vaccinations.

Opponents say it's only a matter of time before scientific evidence turns and finds fluoridation does more harm than good. 

"We used to put lead in our gasoline," says Kimberly Kaminski, executive director of Oregon Citizens for Safe Drinking Water. "We used to insulate with asbestos. We used to give expectant mothers thalidomide. We know that these practices are harmful; fluoridation is no different."

You can expect to hear more of fluoridation opponents' arguments as they try to put the question to Portland voters in a 2014 initiative petition. Here are some of the claims you'll hear opponents make:

Fluoride is poison. Fluoride, which occurs naturally in drinking water, is indeed a neurotoxin. As with all poisons, however, it's the dose that matters. Opponents point to warnings on toothpaste tubes urging people to call a poison control center if toothpaste is swallowed. Toothpaste, however, contains more than 1,000 times as much fluoride as fluoridated water. But a full tube wouldn't be a lethal dose for even a 2-year-old, 22-pound child, according to the Columbia University College of Dental Medicine.

Fluoride causes developmental problems in children. A 2012 study by Harvard researchers gives opponents ammunition: An analysis of 27 studies conducted in China found children's average IQs were a half-point lower in areas with high fluoride levels. The analysis was plagued by insufficient data, and fluoride concentrations were almost all three to 10 times higher than would be placed in drinking water here.

Fluoride can harm your bones. Both sides agree "fluorosis"—a discoloration or loss of tooth enamel—is a possible side effect of too much fluoride in the water. Foes say dental fluorosis is also evidence of a systemic attack on your bones. "Skeletal fluorosis" does happen, but peer-reviewed studies show an adult would have to drink 42 8-ounce glasses of fluoridated water a day for 10 years before it posed a clinical risk.

Fluoride causes cancer. A study published in 2006 by a Harvard doctoral student found a link between longtime exposure of boys ages 6 to 8 to fluoridated water and osteosarcoma, a rare form of bone cancer. Harvard researchers, however, say the finding was never backed up. Opponents cite this study (and an alleged cover-up of it) as proof of fluoride's harm. Proponents cite a follow-up study, culled from the same data, that showed no link to bone cancer.

Fluoride isn't as effective as proponents say. Foes say tooth-decay rates are falling without fluoridated water, thanks to overall better dental health. Supporters say countless studies show fluoridated water still reduces tooth decay—and low-income communities benefit most. A 2006 study in New York found unfluoridated communities needed 33 percent more dental procedures, even though the number of cavities prevented per person—0.43—was small.

Proponents of fluoridated water say they have been fighting fear and misinformation for years—and they don't expect it to stop now.

"That is a line of thinking that is out of line, in my view," says Eli Schwarz, director of community dentistry at Oregon Health & Science University, "when you say that the government actually wants to poison its own population."