The water fluoridation debate

President-elect Donald Trump has nominated Robert F. Kennedy Jr. to lead the Department of Health and Human Services (HHS) in his administration. Kennedy is notable for being the son of former Democratic Senator Robert Kennedy and nephew of former President John F. Kennedy. He is also a prominent vaccine skeptic and has promoted numerous conspiracy theories related to healthcare. For example, he has advocated for the removal of fluoride from public water (NYTimes).

HHS oversees programs such as Medicare, Medicaid, and the Affordable Care Act, as well as public health initiatives through agencies like the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). It also conducts medical and scientific research via the National Institutes of Health (NIH) and ensures the safety and efficacy of food, drugs, and medical devices (FDA).

Water fluoridation is the process of increasing the fluoride concentration in public water supplies to an optimal level that helps prevent tooth decay and promote oral health. Fluoride, a naturally occurring ion found in soil and water, has been shown to strengthen tooth enamel and reduce the risk of cavities. First introduced in the United States in 1945, water fluoridation is considered one of the most significant public health achievements of the 20th century. By maintaining fluoride levels at safe concentrations, this practice aims to provide widespread dental health benefits, particularly for communities with limited access to dental care. By 2012, 75% of Americans on public water systems consumed fluoridated water, though the rate has since declined slightly.

Public water fluoridation is widely recognized as a safe and effective measure to reduce dental caries (tooth decay) across populations. The Centers for Disease Control and Prevention (CDC) highlights that community water fluoridation prevents at least 25% of tooth decay in children and adults throughout their lifespan.  Similarly, the American Dental Association (ADA) states that studies show fluoride in community water systems prevents tooth decay in children and adults, even with widespread public access to fluoride from other sources such as toothpaste. For example, a systematic review by the Cochrane Collaboration (2015) found that water fluoridation reduced dental caries in children by 35% in baby teeth and 26% in permanent teeth. Observational studies have shown that individuals who grow up in areas with fluoridated water maintain better oral health into adulthood.

As an unintentional case study, Buffalo stopped fluoridation in 2015 during plant upgrades. During this period, local dentists and public health officials began noticing a significant increase in tooth decay, particularly among children and vulnerable populations. Fluoridation resumed in 2023 after public backlash and lawsuits.

Interestingly, water fluoridation is not practiced by most countries. The U.S., Canada, Australia, UK, Ireland, and Singapore comprise roughly 25 countries that fluoridate the public water supply to a greater or lesser extent. Most countries in Western Europe including Germany, France and Italy do not fluoridate their water. 

Mechanistically, fluoridation strengthens tooth enamel through a chemical process that enhances the mineralization of teeth and makes them more resistant to decay. First, fluoride interacts with hydroxyapatite, the hard calcium phosphate mineral (QH) that makes up tooth enamel, to form fluorapatite, which is harder and more resistant to acid attacks from bacteria in the mouth, helping to protect teeth from decay. Second, when teeth are exposed to acids from food, drinks, or bacterial activity, enamel can lose minerals like calcium and phosphate in a process called demineralization. Fluoride promotes the reverse process, remineralization, by attracting calcium and phosphate ions back to the enamel, helping to repair and strengthen it.

Despite its long-standing endorsement by major health organizations like ADA (American Dental Association), CDC and WHO, water fluoridation has also faced ongoing debate and scrutiny over potential risks, prompting discussions about its safety, effectiveness, and ethical implications. More specifically, Robert F. Kennedy Jr. has asserted publicly that fluoride is an "industrial waste" linked to various health issues, including arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease. These allegations are completely unsubstantiated by validated scientific data.

For example, there was one study suggesting a link between fluoride exposure and reduced IQ in children, mainly from high-fluoride areas in developing countries. However, other researchers raised concerns over methodology (i.e. confounding from other factors), as well as the transferability of such findings to areas with regulated fluoride levels (i.e. wealthier nations like the U.S.).

It is known that fluoride can have toxic effects by inhibiting certain enzymes at extremely high concentrations such as 4-8 ppm (mg/L) in the bloodstream can be dangerous to humans. The fluoride level in fluoridated water is about 1 ppm. That sounds like a lot but one would have to continually consume a lot of fluoridated water to raise the body concentration to 1 mg/L. 

One can compare blood plasma fluoride levels in individuals from areas with fluoridated water which typically range from 0.02 to 0.10 mg/L in the U.S. In non-fluoridated regions of Europe, blood levels are often closer to the lower end of this range, around 0.01 to 0.03 mg/L. Both are far below the toxic region of 4-8 mg/L.

Finally, one can ask how much fluoride is in toothpaste. Regular toothpaste contains fluoride at roughly 1000 ppm with prescription toothpaste for those at high risk of cavities at 5000 ppm. Although one does not swallow toothpaste, a small amount may be accidentally ingested. Will the new head of HHS ask for fluoride to be removed from toothpaste?

All of this debate is reminiscent of a famous scene in the movie Dr. Strangelove, when General Jack D. Ripper (played by Sterling Hayden) delivers an unhinged rant about the supposed dangers of fluoridated water (Video 1). This moment was emblematic of the film's satire on Cold War paranoia and conspiracy thinking.

Video 1. In the movie Dr. Strangelove, the character of General Ripper, who has gone rogue and ordered a nuclear strike on the Soviet Union, explains his motives to Group Captain Lionel Mandrake (played by Peter Sellers) in his office. Ripper, smoking a cigar and sitting amidst the chaos he has unleashed, delves into his personal theory about the "communist plot" of water fluoridation. Ripper believes that fluoridation of water is a covert operation by communists to undermine the purity and health of Americans. He claims it's a form of "foreign substance" infiltration to weaken the nation's bodily fluids.