• Kevin Elliott

Despite benefits, fluoride battle goes on

Chances are that if you were a dentist in the early part of the 20th century, the majority of your work involved pulling teeth or fitting folks for dentures, with roughly half of all Americans having dentures by the age of 55. By the year 2000, about nine percent of adults age 45-54 had lost all their teeth, down from 20 percent in 1960, according to the national Centers for Disease Control (CDC).

Today, the largest factor in reducing tooth decay is the use of fluoride, both in toothpaste, varnishes and in the water we drink. First introduced in 1945 in Grand Rapids, today more than 70 percent of the nation's public drinking water is now fluoridated, leading the CDC to name fluoridation of water one of the greatest achievements in public health in the 20th century.

“Water fluoridation is the best method for delivering fluoride to all members of the community, regardless of age, education, income level or access to routine dental care,” according to the American Dental Association. “Fluoride's effectiveness in preventing tooth decay extends throughout one's life, resulting in fewer – and less severe – cavities. In fact, each generation born over the past 70 years has enjoyed better dental health than the one before it. That's the very essence of the American promise.”

Despite the health benefits of fluoridation, there has been a vocal group of skeptics who believe fluoridation may be more harmful than good.

Hardy Limeback, a retired dentist and former head of Preventative Dentistry at the University of Toronto, was one of 12 scientists in North America chosen to serve the National Academy of Science's committee that produced the “Fluoride in Water” report in 2006. While the report supported the use of fluoride in water, Limeback said he has since changed his mind.

“I was mistaken,” he said. “It became clear to me that even at low chronic daily intakes of fluoride, such as those provided by fluoridation, susceptible and vulnerable groups of the population can experience ill health effects.”

Limeback said research shows water fluoridation accumulates in bones in adults to high levels at which bone is at risk of fracture. Further, he said significant and severe dental fluorosis – a condition marked by stained and pitted teeth – is a potential for children, especially when fed infant formula made with fluoridated water.

Other claims from water fluoridation opponents range from those based on solid scientific research to political conspiracies that fluoridation was introduced as part of a Communist plot to control the United States population. Such wild conspiracies were even included in the 1964 black comedy, Dr. Strangelove:

“Mandrake, have you ever seen a commie drink a glass of water. … Do you realize that fluoridation is the most monstrously conceived and most dangerous communist plot we have ever had to face,” character Brig. Gen. Jack Ripper said in the film.

In 2015, the U.S. Department of Health and Human Services (HHS) lowered the recommended optimal level of fluoride in drinking water to prevent tooth decay from 1.2 milligrams per liter to .7 milligrams per liter, or .7 parts per million (ppm).

The change, the first since it was issued by the department in 1962, was recommended because people now have access to more sources of fluoride, such as toothpastes and mouth rinses, than they did when water fluoridation was first introduced.

The lower standard has provided more fuel to the fluoride debate, which has been discussed in one form or another since it was first added to public drinking water systems.

Take, for instance, truther Alex Jones with the website Info Wars who has made outlandish claims about water fluoridation: “What do you think water is? It's a gay bomb, baby,” he has said in regard to fluoridation.

While such beliefs are often disregarded as fringe conspiracies, they also provide a disservice to legitimate research regarding fluoride and its potential health effects.

In the United States, the most common issue associated with excessive fluoride exposure is a dental condition known as fluorosis. The condition, which can cause small white spots in mild cases, and pitting and dark stains in more rare cases, is caused by excessive exposure to fluoride as a child. Such levels are related to naturally occurring fluoride in drinking water sources, and not those related to water fluoridation.

As excessive amounts of fluoride does indeed have detrimental health impacts – the U.S. Environmental Protection Agency (EPA) sets a maximum contaminant level of fluoride in drinking water at four ppm. However, the department has said that level is being reviewed and may be lowered in the future.

The EPA also maintains a “non-enforceable” secondary standard for fluoride of two ppm, which is recommended to protect against moderate and excessive fluorosis. Levels above four ppm may lead to crippling skeletal fluorosis, a condition that is characterized by pain and tenderness of major joints.

“In some countries, it has been considered a risk to public drinking water, but in most of the United States there hasn't been much concern,” said University of California San Francisco Professor Howard Pollick, who chairs the California Fluoridation Advisory council and is a national expert on the issue. “About half of the population – it varies from place to place – will drink and cook with (fluoridated) tap water and make beverages with tap water. And it's not just drinking water, it's also cooking and having food processed that conveys a benefit. Small concentrations of fluoride really do make a difference.

“In terms of what we know and what's credible and what isn't – I love working with the internet, but the internet is replete with information, or disinformation, on fluoridation, vaccinations and other issues. And we see that people are susceptible to information they get from friends and the internet. It's a constant struggle.”

One of the largest and most outspoken anti-fluoridation groups on the internet is the Binghamton, New York-based Fluoride Action Network (FAN). The group's website has a wealth of information, including both generally accepted studies, as well as more outlandish claims, such as the premise that fluoridated water may have exacerbated the lead water crisis in Flint.

For instance, a 2016 article on the site stated that fluoride can be corrosive, which in itself is credible. However, the article failed to distinguish water with fluoride at one ppm or less and extremely high levels of fluoride that may be used in an industrial setting. Omitting this important distinction, the article said fluoridation programs are “adding fuel to the fire of America's lead crisis, in Flint and beyond” – never mind the fact that Flint's water had been fluoridated for decades prior to the lead crisis that was caused by the city's failure to provide an anti-corrosive measure in its water after switching from the Detroit water system as a provider.

The FAN story also referred to high lead found in children's blood in six other Michigan cities, which coincidentally fluoridate their water. The article failed to mention that most, if not all, of those levels reported by the MHHS have been linked to lead paint.

Still, in speaking with FAN Executive Director Paul Connett, he said his concerns are based on research that had been accepted by reputable science journals and experts in the field.

“The most immediate concern is for the impact of fluoride on the thyroid gland, which in a pregnant mother could impact a baby's IQ,” he said. “That's a big issue that should have been understood before fluoridation started.”

Connett said the issue may or may not be the cause of lowering IQs cited in more than 50 studies that found lowered IQs in villages with high levels of fluoride. He also cited a National Institutes of Health (NIH) study released in 2017 that found a strong association of fluoride exposure as measured in the urine of pregnant women.

“They measured those levels and IQ, and they found that as the fluoride level went up, that IQ went down, by about five to six IQ points,” he said. “On an individual level, that's not a huge amount, but what that means on the population level is incredibly important.”

To better understand the sources of fluoride and its relationship to human health, it's helpful to understand the origins of its use as a health benefit.

While the first city in the United States to implement fluoridation was Grand Rapids in 1945, the story of fluoridation began nearly 50 years earlier with a condition dubbed Colorado Brown Stain.

According to the National Institutes of Health, dentist Frederick McKay opened a practice about 1901 in Colorado Springs. It was there that McKay discovered natives of the city suffering from permanent brown stains on their teeth, the color of chocolate. After studying the condition with others, it was discovered the condition developed before permanent teeth had fully grown in, and that the affected teeth were oddly resistant to tooth decay. The condition was linked to the water supply, but it wasn't until 1931 when a researcher at ALCOA discovered the water had high levels of naturally occurring fluoride.

The findings eventually led researchers at the U.S. Public Health Services to look into fluoride and its impacts on tooth enamel. By the late 1930s, researchers with the National Institutes of Health learned that levels of up to one ppm in drinking water caused only mild fluorosis in a small percentage of people.

Building on the previous findings, researchers hypothesized that low levels of fluoride would help fight tooth decay. In 1944, the Grand Rapids City Commission was approached and approved testing the idea with the city's water supply, under the guidance of the Public Health Services, the Michigan Department of Health and other public health organizations.

Starting in 1945, fluoridation in Grand Rapids was to be tested for 15 years, with the city of Muskegon serving as the control city. The researchers monitored almost 30,000 schoolchildren during the study. After 11 years, it was found that cavity rates had dropped by more than 60 percent, marking a giant scientific breakthrough.

Pollick of University of California said the initial studies established the scientific evidence that an optimum concentration of fluoride to prevent cavities was about one ppm, while communities with more than two ppm would have a portion of the population with severe forms of dental fluorosis.

“It's a very fine line between one ppm and two ppm. A very small amount would be a big difference,” he said. “Usually, fluoride is found in rocks with phosphate and calcium or aluminum. It's not usually found by itself, so those rocks can be a source for that and other things.”

Going back to studies that correlate loss of IQ to fluoride exposure, proponents of fluoridation say those changes have been shown, but ring true in areas where fluoride levels are particularly high.

“Fluoride in the wrong amount can be toxic, but the concentration we are talking about to demonstrate toxicity is much higher,” said Carlos Gonzalez-Cabezas, a professor with the University of Michigan School of Dentistry who serves as director of the school's Global Initiatives in Oral and Craniofacial Health, and has specialized in research involving fluoride. “It's not surprising. It was used in rat poison decades ago, so it's not surprising that there's a need for continued research, as there could be populations that are more susceptible to it. But that's not just with fluoride, that's with anything, especially young ones.”

Gonzalez-Cabezas said there has been research from China and Mexico that have shown high concentrations of fluoride can reduce IQ, but it isn't comparable to levels in the United States.

“Most teens may have dental fluorosis, but there's no influence other than aesthetically, and you can only see it with a microscope. You can have more advanced levels with pits in the surface of the tooth, but that usually doesn't happen in the United States. Usually, that's in Mexico or other areas where they are drinking from wells with high concentrations of fluoride, maybe four ppm or eight ppm,” he said. “In China, they had levels so high from the consumption of fluoride that bones and joints will deform. We don't see that in the U.S. In those cases, they were drying vegetables with coal and it had a lot of fluoride, and that was only a percentage of the community. There were some that are more genetically susceptible than others.”

While the issue should continued to be studied, he said fluoridation in the United States still remains a great health benefit and should be continued.

“Fluoridation, personally, the importance today is most for people from people from lower socioeconomic groups, and the least for those from higher groups,” he said.

As results of the early studies from Grand Rapids were released in the late 1950s, other cities began following suit and fluoridating their water.