Facts on fluoride in water, salt and toothpaste

Robert F. Kennedy Jr. — the son of assassinated US Attorney General Robert F. Kennedy and nephew of assassinated President John F. Kennedy, as well as supporter of Donald Trump and renowned vaccine skeptic — could be the country’s next health  secretary.
And Kennedy has big plans for the job. In a social media post, Kennedy announced that upon Trump’s inauguration, water fluoridation in the U.S. would be stopped.
He claims that fluoride is industrial waste and responsible for bone cancer, neurological developmental disorders, lower IQs in children and more. 
Fluoride is often confused with fluorine in common usage. Fluorine is a highly corrosive and toxic gas with a pungent odor. When it reacts with water, it forms hydrofluoric acid, also known as fluorine acid. 
Fluorides, on the other hand, are salts of hydrofluoric acid. They occur naturally in various minerals and in the human body, primarily in bones and tooth enamel, but also in blood and gastric juice.
Natural sources of fluoride include black and green tea, fish and asparagus. 
In Germany, fluoride is added to toothpaste and table salt; in many other countries, including the United States, it is also added to drinking water. 
Fluoride naturally occurs in small amounts in water. In the early 20th century, scientists observed that higher levels of natural fluoride in certain regions of the U.S. were associated with lower rates of dental cavities in children.
This discovery led to the practice of adding fluoride to drinking water in other areas, which remains a common practice today. 
“A certain amount of fluoride is beneficial for dental health,” toxicologist Carsten Schleh said.
Fluoride is not essential for human survival, but it aids in the remineralization of tooth enamel, thereby reducing the risk of cavities.
Fluoride is used globally in toothpaste, salt, and drinking water as a cost-effective measure to prevent cavities. It has been hailed by the U.S. Centers for Disease Control and Prevention (CDC) as one of the top ten public health interventions of the 20th century. 
Not everyone is celebrating fluoride, as Kennedy’s post illustrates. In some circles, fluoride has been labeled a toxin blamed for various health issues. 
Fluoride’s bad reputation is largely undeserved, Schleh said: “As with anything, the dose makes the poison.”
Overdosing on fluoride is nearly impossible with toothpaste, as it is typically spit out rather than swallowed. 
The situation is different with fluoridated drinking water or table salt. The CDC states that 0.7 mg of fluoride is added per liter of water, which aligns with the recommended daily dose for toddlers aged one to four, according to Germany’s Federal Institute for Consumer Health Protection and Veterinary Medicine (BgVV). 
For adults, the institute advises against exceeding 3.8 mg of fluoride per day. Overdose in children can cause white spots on teeth, known as fluorosis, while higher doses can lead to brown tooth discoloration. 
Long-term excessive intake of 10-25 mg per day can result in skeletal fluorosis, leading to bone fractures and joint deformities. Extremely high fluoride consumption, between 300 and 600 mg daily, can cause kidney damage. 
A 2023 meta-analysis explored whether fluoride in drinking water could harm brain development. Researchers concluded that the fluoride concentrations deemed safe by the CDC might indeed have negative effects on brain development and children’s intelligence. 
The authors noted that their findings could be skewed by the varying quality of the studies analyzed, with “a general tendency for weaker or no associations in the most rigorously conducted studies.” 
Another meta-analysis found that IQ reductions, if any, occur only when fluoride intake exceeds recommended levels. Based on available evidence, it is not possible to definitively conclude whether fluoride causes any form of neurological disorder. 
If fluoride is removed from US drinking water starting January 20, Schleh predicts no decline in neurological disorders but potentially an increase in cavities among children and adults. 
This article was translated from the German original.
Sources:
CDC: About Community Water Fluoridation (2024)
Environmental Research: Fluoride exposure and cognitive neurodevelopment: Systematic review and dose-response meta-analysis (2023). DOI: 10.1016/j.envres.2023.115239
Nature: A systematic review and meta-analysis of the association between fluoride exposure and neurological disorders (2021). https://doi.org/10.1038/s41598-021-99688-w
Bundesinstitut für gesundheitlichen Verbraucherschutz und Veterinärmedizin (BgVV): Verwendung fluoridierter Lebensmittel und die Auswirkung von Fluorid auf die Gesundheit (2002)