Fluoridation of the U.S. public water supply has been a polarizing topic both academically and politically since its start in the 1940s. Debate over its benefits and health risks has raged on as the science has continued to unfold.
This series will explore the contentious findings surrounding this ubiquitous public health measure and answer the question of whether water fluoridation poses a risk and what we should do about it.
We’ve all grown up being told that fluoride is good for our teeth. Some experts thought it was so good for the health of our teeth that in the 1940s, the U.S. government decided to start adding synthetic fluoride to the U.S. water supply.
From very early on, there have been conflicting views and significant debate within the scientific, medical, and dental communities over the merits of fluoride. In her paper
published in The American Journal of Public Health in 2015, historian Catherine Carstairs recounts that in the late 1940s and early 1950s, this debate largely ended with experts opposed to the fluoridation program being dismissed “as cranks and quacks,” and relegated to the so-called fringes by their peers.
After more than 70 years, the battle between the pro-fluoride and no-fluoride camps wages on. At the heart of that battle are questions about how effective water fluoridation is at preventing dental decay and whether the possible adverse health risks are worth the benefits.
The big guns on the pro-fluoridation side, such as the American Dental Association
and the Centers for Disease Control and Prevention
(CDC), support community water fluoridation as an effective way to prevent tooth decay.
Both groups say the safety and benefits of fluoride for preventing tooth decay in both children and adults are “well documented and have been reviewed” by several “scientific and public health organizations.”
claims there has been “no convincing scientific evidence” found “linking community water fluoridation with any potential adverse health effect or systemic disorder such as an increased risk for cancer, Down syndrome, heart disease, osteoporosis and bone fracture, immune disorders, low intelligence, renal disorders, Alzheimer’s disease, or allergic reactions.”
But the actual science is less one-sided than the CDC suggests. A 2018 research review
published in Preventative Nutrition and Food Sciences looked at both the pros and cons of fluoridation.
"Major concerns about excessive fluoride intake and related toxicity were raised worldwide, leading several countries to ban fluoridation," it noted.
Opponents of water fluoridation include the Fluoride Action Network
(FAN) and Food and Water Watch. Their criticism focuses
on the possible health risks revealed in more than 100 published studies showing the harmful effects of fluoride including neurotoxic harm, reduced IQ, damaged kidneys and liver, suppressed thyroid hormones, and brittle bones.
While it's fairly well established that putting fluoride on the teeth can help combat cavities, there is less clarity around the benefits of drinking it. Advocates of water fluoridation point to population-level data to support these programs.
An October 1999 Morbidity and Mortality Weekly report
from the CDC noted that early studies reported that water fluoridation can reduce tooth decay by 50 percent to 70 percent.
The report stated that between 1960 and 1970, unpublished data showed that the new fluorination program reduced decayed, missing teeth due to caries, and filled teeth in the permanent teeth of 12-year-olds by 68 percent.
But, the report said, a later review of studies on the effectiveness of water fluoridation conducted in the United States from 1979 to 1989 found that caries reduction was 8 to 37 percent among adolescents.
Part of the problem with the data is that better dental hygiene practices, including the introduction of fluoride toothpaste came about at the same time as water fluoridation programs.
Studies conducted after this change cited by the Fluoride Action Network
further discount the dental benefits of water fluoridation.
One of their cited studies
done between 1986 and 1987 and submitted for publication in the Danish journal Community Dentistry & Oral Epidemiology looked for dental caries in 39,207 school children 5 to 17 years old across 84 different geographical areas.
This study found no statistically significant difference between the number of dental caries in the fluoridated verse the non-fluoridated groups across all age groups.
Today, the CDC says
that water fluoridation reduces tooth decay by about “25 percent in children and adults,” and the agency has named community water fluoridation as “1 of 10 great public health achievements of the 20th century,” because it has “contributed to the dramatic decline in tooth decay over the past 70 years.”
A Harvard review of data gathered by the Organization for Economic Cooperation and Development
is less glowing. Looking at the average number of decayed, missing, or filled teeth between 1975 and 2014 in different countries, it compared nine countries that fluoridated their public water to 22 countries that didn't.
Per a Harvard Public Health Magazine article
, the data showed that countries that didn't fluoridate their water had also seen similar drops in cavity rates over that time period.
Despite more than 73 percent
of the U.S. population currently being on a fluoridated community water system, tooth decay
remains the most prevalent chronic disease in both children and adults, even though it's largely preventable.
The Battle Wages On
This 70-year battle reached a new level in 2017, when a landmark lawsuit
by a coalition of groups including the FAN and the Food & Water Watch was filed against the Environmental Protection Agency to “protect the public and susceptible subpopulations from the neurotoxic risks of fluoride by banning the addition of fluoridation chemicals to water.”
Because of many delays brought on by the EPA, this David-and-Goliath battle is still ongoing, with its next scheduled court hearing on April 11.
The suit has brought into question annual fluoride participation awards
given to communities across the United States by the CDC, Association of State and Territorial Dental Directors, and the American Dental Association.
The case also recently revealed government attempts
to limit available evidence and avoid having the facts of water fluoridation reviewed in court.
Per court order, the suppressed National Toxicology Program’s (NTP's) draft review
has recently been made public.
The NTP’s "2019 Systematic Review of Fluoride Exposure and Neurodevelopment and Cognitive Health Effects" concluded that “fluoride is presumed to be a cognitive neurodevelopmental hazard to humans.” They state that “this conclusion is based on a consistent pattern of findings in human studies across several different populations showing that higher fluoride exposure is associated with decreased IQ or other cognitive impairments in children.”
Per the NTP, the National Academies of Sciences, Engineering, and Medicine committee criticized the NTP's classification of fluoride as a cognitive neurodevelopmental hazard for humans, saying they hadn't adequately supported its conclusions. The May 2022 draft, although public, is still under review and not yet finalized.
Over the next several articles, we’ll take a closer look at the toxicity profiles of fluoride additives, the controversy around how they’re made, and the questionable scientific research that the fluoridation of the U.S. public water supply was based on.
In the next article:
The fluoride additives in our public water system aren't naturally occurring, which opponents and chemical data research suggest make them even more toxic to human health.