What Israel can teach us about water fluoridation — or the lack thereof

U.S. Health Secretary Robert Kennedy Jr. vowed in April to tell the Centers for Disease Control and Prevention to stop recommending community water fluoridation. One month later, Utah and then Florida passed legislation to prohibit public water fluoridation.

The controversy about water fluoridation is nothing new. Fluoridation was considered a communist conspiracy in the 1950s and figured in the plot of the 1964 movie “Dr. Strangelove.” I decided to research the benefit of adding fluoride to water and the harm of too much fluoride. I also looked at what happened in Israel when fluoridation was stopped in 2014.

What is fluoride? It is a natural mineral that binds with calcium and phosphate on the surface of the tooth to make enamel stronger.

In 1945, Grand Rapids, Michigan, became the first city in the world to fluoridate its water supply, and 11 years later tooth decay in children dropped by more than 60%. San Francisco and Antioch, California,followed suit in 1952. A decade later, school children in Antioch had greater than 55% reduction in tooth decay.

The CDC has named fluoridation of drinking water as one of the top 10 public health achievements of the 20th century. However, most of the studies advocating the benefits of water fluoridation were done before 1975 and did not consider the benefits of adding fluoride to toothpaste, which began in the mid-1950s. I looked at more current research and to my surprise, the most recent evidence supporting fluoridation is modest. A2024 analysis combining 157 studies from the Cochrane Database found that water fluoridation resulted in prevention of dental decay of one-quarter of a tooth compared with those who did not drink fluoridated water.

What might be the harm of water fluoridation? The most commonly observed effect of excessive fluoride is a condition called fluorosis. It can appear as flecks, lines or spots on a tooth, and it is mainly cosmetic. The U.S. Public Health Service currently recommends a fluoride concentration of 0.7 parts per million (ppm) in water to prevent dental caries and balance the risk of fluorosis. To put this number in perspective, nearly all fluoride toothpaste has concentrations of at least 1,000 ppm, and there is no evidence of any significant harm from brushing as directed with this.

Why have fluoridated water if you are using fluoridated toothpaste? The answer is that the combination is complementary. Fluoridated water provides a constant amount of protection during the day, and fluoridated toothpaste can provide a concentrated amount before bedtime. Fluoridation especially helps the most vulnerable among us: low-income families with little access to dental care.

Opponents of water fluoridation have questioned fluoride’s effect on children’s IQ. In a 2024 analysis combining 74 studies, an association was found between higher fluoride exposure and lower IQ scores for children. However, most of the studies in the analysis were low quality, and none of the studies was done in the U.S. There was no data to indicate that the fluoride concentration of 0.7 ppm affected children’s IQ.

Here are two examples of the harm in adults from very high amounts of fluoride, far higher than the amounts used in water fluoridation.

This first example is an unusual case of skeletal fluorosis reported in theNew England Journal of Medicine in 2013. A 47-year-old woman was evaluated for bone pain and abnormal X-rays of the bones in her forearm and spine. She was found to have a very high serum concentration of fluoride and diagnosed with skeletal fluorosis. The explanation was that for 17 years she had consumed a pitcher of tea daily made with 100-150 tea bags. The tea plant is a hyper-accumulator of fluoride, absorbing it from air and soil. After counseling, she stopped drinking tea and noticed improvement of her symptoms.

This second example of fluoride harm is from research on treatments for osteoporosis. Because fluoride can increase bone mass, a four-year trial was done to treat women with osteoporosis with fluoride. The results published in 1990 in the New England Journal of Medicine showed unexpectedly that non-spinal bones became more fragile in the group of women who received sodium fluoride. They also had significantly more fractures compared with the placebo group.

So what can we learn from Israel? In 1981, Israel implemented water fluoridation, but in 2014 the health ministry decided to stop the practice. Because of budgetary issues, it was not restarted. A follow-up study in 2024 showed that the number of dental restorations and crowns had since doubled in 3- to 5-year-old children. The authors of the study concluded that Israel should restore community water fluoridation. But that has yet to happen.

In summary, the benefit of water fluoridation may be modest. But there is no evidence of harm from the low concentration of fluoride in the U.S. water supply. Kennedy could learn from Israel’s experience that stopping water fluoridation results in harm to young children — something no one should want.