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Fluoride in water in the United States and public health misinformation: Research review

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A 2014 review paper in The Lancet Neurology identified a number of potential development neurotoxins in children, including manganese, fluoride, chlorpyrifos, tetrachloroethylene, dichlorodiphenyltrichloroethane and the polybrominated diphenyl ethers. One of these — fluoride — has continued to fuel a discussion since the article’s publication, as the water supplies of approximately 74 percent of the U.S. population have fluoridation. While the debate hasn’t yet risen to the same level as those over vaccines or global warming, some U.S. municipalities are reassessing the amount of fluoride in their water sources — or whether to fluoridate at all.

Journalists and communicators of all kinds should review the best research and the history of misinformation on the topic, and to avoid false balance — “he said, she said” characterizations — where the science remains definitive. In particular, not examining the dose in question — levels of fluoridation proposed or studied — can lead to faulty reporting.

History and state of the field

U.S. towns and cities started adjusting the amount of fluoride in their water about 70 years ago when research linked increased fluoride levels to improved dental health. Supporters of fluoridation state that it leads to healthier communities — and is economical and easy. While recognizing the important balance of effectiveness, dose and safety, the leading scientific and health groups are overwhelmingly pro-fluoridation. In April 2015, the U.S. Department of Health and Human Services recommended reducing the level of fluoride in drinking water to 0.7 milligrams of fluoride per liter of water. Its previous recommendation, outlined in its 1962 Drinking Water Standards, ranged from 0.7–1.2 milligrams of fluoride per liter of water.

Among the groups supporting fluoridation are the American Dental Association, the American Medical Association and the World Health Organization. The American Dental Association has called community water fluoridation “one of ten great public health achievements of the 20th century.” In a video posted to YouTube in December 2015, U.S. Surgeon General Vivek Murthy credited water fluoridation with helping reduce the prevalence and severity of tooth decay.

The CDC summarizes the chronology of the leading research by the U.S. National Academy of Sciences. The American Association of Dental Research held a special session during their 2014 annual meeting titled “Water Fluoridation: Safety, Efficacy and Value in Oral Health Care.” Outcomes from this meeting include general consensus that no scientific evidence exists to support the claimed negative health effects of fluoridation other than fluorosis — a change in the appearance of tooth enamel that can include white spots, staining and pitting. According to the CDC, dental fluorosis occurs when young children take in too much fluoride over a long period, when their teeth are forming under their gums.

Opposition background

Despite the evidence supporting the safety and efficacy of fluoridation, anti-fluoride critics have extended their influence and challenged public health experts. They claim that fluoride in drinking water has led to rising levels of fluorosis and can increase the risk of cancer. Some communities even reject fluoridation. For example, voters in Portland, Oregon did so in 2013, the fourth time in almost 60 years — overruling the city’s commissioners, who had agreed to fluoridate the city’s water supply. In January 2016, city officials in Durango, Colorado were debating whether to stop adding fluoride to city drinking water. In early 2016, residents of Healdsburg, California and those in Collier County, Florida were pushing their leaders to do the same thing.

Anti-fluoride groups such as the Fluoride Action Network have effectively used social media to convey their message, and some have lobbied the EPA’s Office of Water to “determine a scientifically based (not politically influenced) MCLG (maximum contaminant level goal) for fluoride.” However, the EPA and the Department of Health and Human Services base their current fluoridation recommendations on their own rigorous scientific assessments and on those of the National Academy of Sciences, all of which take into account the balance of dose, risk and health benefits.

The “Harvard study” and its limitations

In 2012, a review of studies linking high fluoridation levels with reduced IQ scores was published in Environmental Health Perspectives. Nicknamed the “Harvard study,” this report combined the results of 27 studies and found that “children in high­ fluoride areas had significantly lower IQ scores than those who lived in low­-fluoride areas.” The review concluded that the “results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment.” Experts writing in The Lancet criticized the study for a variety of serious flaws, however. Media outlets such as the Wichita Eagle dug into the research, and found that 25 of the studies analyzed took place in China, where natural fluoride levels were much higher than those in controlled U.S. public water systems. But that did not stop Witchita officials and groups from using the study to help persuade voters to reject fluoridation.

In any discussion of the “Harvard study,” it might be noted that the Deans of the Harvard Medical School, Harvard School of Dental Medicine and Harvard School of Public Health have publicly expressed their support for fluoridation.

Useful studies for background

The following are authoritative research studies and accounts of fluoride; they serve as useful citations for communicators reporting on related issues:


Keywords: local reporting, safety, science

    Writers: and | Last updated: January 12, 2016

    1 comment

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    Janet Nagel, EdD Aug 15, 2014 22:07

    Your post “Fluoride in water in the US…” by Brittany A. Seymour is selective and misleading. It is a serious disservice to journalists and their readers and viewers.

    Most importantly, the report fails to recognize that claims that fluoridation reduces tooth decay by some fraction are not relevant because this is the United States of America, not North Korea or some other country where human rights are disregarded. The error of fluoridation is spelled out irrefutably in the 2005 UNESCO Universal Declaration on Bioethics and Human Rights:

    “Any preventive, diagnostic and therapeutic medical intervention is only to be carried out with the prior, free and informed consent of the person concerned, based on adequate information. The consent should, where appropriate, be express and may be withdrawn by the person concerned at any time and for any reason without disadvantage or prejudice.” Article 6 – Consent

    The UNESCO declaration is a reiteration of the Nuremberg Code promulgated in the trials of the National Socialist physicians who committed atrocities during WWII.

    The reason that ethical public health practice requires individual consent is because the nature of the scientific method is such that medical science can never guarantee that any treatment or procedure will not harm anyone, whether or not specific harm has been identified.

    In the case of fluoridation, the instigators announced from the outset that it would cause some degree of dental fluorosis, an adverse effect recognized by them and everyone else. The claim of fluoridators is that dental fluorosis is acceptable injury.

    What extreme exigency would require water suppliers to knowingly inflict injury–cosmetic or otherwise–on water consumers and thereby violate the fundamental human rights that underpin our society?

    Tooth decay? How is that sufficient cause when regular tooth brushing is clearly more effective, ethical, safer and less costly? Citizens are entrusted with responsibility for diet, exercise and every other health maintenance practice. Why would a dental treatment be imposed on them? Because it can be?

    The ongoing debate over whether or not dozens of clinical and epidemiological studies are sufficient evidence of harm from fluoridation are beside the point in view of the ethical constraint on this practice.

    Furthermore, besides the universally recognized risk of dental fluorosis, research officially ordered by the US government (National Toxicology Program, 1990) found links to bone cancer and liver cancer fully 24 years ago. According to standard EPA policy, this should have triggered a new regulation which would preclude fluoridation in the US, but EPA administrators refuse to promulgate that regulation. https://www.youtube.com/watch?v=nIbJausU84w (Fluoride Politics, a six minute documentary)

    Further obviating fluoridation: In 1999 the US Centers for Disease Control (CDC) announced a new scientific consensus that “fluoride prevents dental caries predominately after eruption of the tooth into the mouth, and its actions primarily are topical for both adults and children.” The National Research Council of the US National Academies of Science concurred, stating in 2006 that “the major anticaries benefit of fluoride is topical and not systemic.” Clearly toothpaste or mouthwash are more effective and controllable methods of bringing fluoride into contact with tooth surfaces.

    Public officials who promote fluoridation are failing their obligation to adhere to ethical health care practices. They should be focusing on education of children, parents and the general citizenry, as they do with all other health issues.

    Quarantine to stop the spread of ebola is a legitimate exercise of public health police power. Treating entire populations indiscriminately with fluoride by injecting it into the common water supply is an illegitimate exercise of public health police power.

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