The soon-to-be President Donald Trump has reportedly selected Robert F. Kennedy Jr. as his Secretary for Health and Human Services, with a commitment to prioritize health care reforms in his second term. Although the specific policies are yet to be disclosed, Kennedy has hinted at revisiting the fluoridation of water systems across the United States.

His ability to implement changes will depend on his nomination and subsequent Senate confirmation in 2025. On a social media platform, Kennedy expressed his intentions to advocate for the removal of fluoride from the nation's water supply, citing its alleged links to a range of health issues including arthritis, bone fractures, bone cancer, reduced IQ, neurodevelopmental disorders, and thyroid diseases. Fluoride, a naturally occurring mineral found in trace amounts in various environmental mediums, is known to strengthen teeth and prevent cavities when present at optimal levels. Different countries have adopted diverse strategies to ensure children receive adequate fluoride, such as adding it to water, milk, or salt, or providing fluoride varnishes and mouthwashes in schools.

The practice of community water fluoridation was first introduced in the United States in 1945 as a cost-effective and equitable means to enhance oral health. The CDC has recognized water fluoridation as one of the top 10 greatest health achievements in the 20th century in the United States, alongside other significant interventions like vaccination and family planning.

As of 2022, approximately 72% of the U.S. population has access to fluoridated drinking water, with this figure varying significantly among states, from a low of 8.5% in Hawaii to a high of 100% in Washington, D.C. Water fluoridation is not mandatory, and the CDC's recommended fluoride concentration of 0.7 milligrams per liter is a guideline rather than a regulation. The decision to fluoridate water is made at the local level, contingent on the natural fluoride content.

According to publicly available data on the CDC's website, there are 36,767 water systems in 36 states with information on fluoride content. As of 2023, only 37% of these systems are fluoridated, with this percentage varying by state. For instance, in Kentucky, 93.8% of reported water systems are fluoridated, while in Alaska, only 3.7% are. There is also considerable variation in the fluoride levels across these water systems. Not all 36 states report fluoride concentration levels, which limits comprehensive analysis.

Among those that do, 24 states report fluoride levels in 1,774 public water systems, with 53% of these systems having fluoride concentrations within the recommended range of 0.7mg to 1.2mg per liter. Nearly half of these systems (47%) have fluoride concentrations below the CDC's recommended level. Two water systems in South Carolina reported fluoride concentrations exceeding the WHO guidelines, which warn that long-term exposure to fluoride levels above 1.5 milligrams per liter can lead to health problems.

Fluoride's benefits for strengthening teeth and bones are well-established, leading to its addition to food and tap water for decades. The CDC attributes a 25% reduction in cavities in children to community fluoridation. Cavities can cause significant discomfort and sensitivity, affecting speech and eating, and can lead to tooth loss or infections that may spread throughout the body. However, at certain concentrations, fluoride can be harmful. The WHO notes that while fluoride reduces dental caries, it can cause tooth enamel and skeletal fluorosis at higher levels after prolonged exposure. Skeletal fluorosis is a severe condition characterized by bone weakness, stiffness, and joint pain.

Numerous studies have demonstrated that fluoridated water can prevent tooth decay and improve oral health. A 2010 study in Nevada found that communities with fluoridated drinking water had lower rates of decayed, missing, or filled teeth. In 2011, Calgary, Canada, removed fluoride from its water supply due to skepticism about its benefits and cost-cutting measures.

A subsequent study comparing children in Calgary with those in Edmonton, where water remained fluoridated, showed that Calgary's children experienced more tooth decay in their primary teeth over three years, suggesting that fluoridated water was a significant source of fluoride for that community. However, other studies have found that advancements in oral hygiene awareness and dental practices have reduced the benefits of fluoridated water. A recent report concluded that while water fluoridation does help prevent cavities, its effectiveness is less than previously believed, with improvements in cavity prevention more likely due to the widespread use of fluoride in toothpaste and mouthwash. International data supports this, showing a decrease in tooth decay globally since the 1970s, even in countries without water fluoridation.

Countries that do not fluoridate water often adopt alternative oral health strategies, such as providing fluoridated milk to schoolchildren in Manchester and Blackpool in the UK. In the rest of the UK, approximately 10% of the population has access to fluoridated water, either naturally or through local programs. In Iceland, schools offer fluoride rinse programs, with children receiving bi-monthly rinses. Japan initiated a similar school-based fluoride mouth-rinse program in 1970, which has since expanded to nurseries.

Research indicates that these fluoride mouth-rinse programs are more effective in reducing cavities when started at younger ages. In Italy, the Society of Paediatric Dentistry recommends a range of interventions for children, including brushing with fluoride toothpaste twice daily and reducing sugary foods and drinks. High-risk individuals are advised to use fluoride tablets, varnishes, gels, or sealants based on their age.

However, excessive fluoride exposure can lead to adverse effects. A study published in May found that higher fluoride exposure during pregnancy was associated with increased neurobehavioral problems in children. An August federal review of existing research found that higher estimated fluoride exposure, exceeding the WHO guidelines of 1.5mg/L, was linked to lower IQ in children. Such levels are rarely seen in the U.S.

Water fluoridation is particularly beneficial for disadvantaged communities and families who may not have access to or be culturally inclined to seek dental hygiene and services, according to water researcher John Fawell, a visiting professor at Cranfield University. Fawell, who has advised the WHO on water quality standards, added that while some epidemiological studies have associated lower concentrations of fluoride with a small reduction in IQ in children, the absence of a clear mechanism means this remains an association and not necessarily a causal link.