On Nov. 2, Robert F. Kennedy, President-elect Donald Trump’s pick for U.S. Health Secretary, claimed via the social media platform X, formerly known as Twitter, that the Trump White House will advise all U.S. water systems to remove fluoride from public water, citing it as an industrial waste associated with a number of health risks.

Kennedy’s claim sparked recurring controversies and left public health officials urging people to do their research before jumping to any conclusions.

What is fluoride, and how does it get in our water?

According to the American Dental Association, fluoride is a naturally occurring mineral that helps prevent tooth decay.

Johnson County Public Health Coordinator Becky Hackett-Leas said fluoride leaches out of rocks naturally and has been present since rocks formed.

Water systems in Coralville and Tiffin have naturally high levels of fluoride in the water, but other water systems, like the city of Iowa City, add fluoride in as a preventative health measure.

What is the history of fluoridation?

Fluoride has been in public water longer than most anyone can remember.

“We’ve had community water fluoridation for more than 75 years. Next year will be year 80 since those first studies began to adjust the community water fluoridation to the optimal level,” said University of Iowa College of Dentistry Professor Steven Levy.

Before water fluoridation, overall dental health was much poorer compared to today, Levy said. Cavities and tooth extractions were far more common.

“There are literally tens of millions of teeth in the mouths of middle-aged and older adults that a couple generations ago would have been extracted — the large majority of adults over age 65 had no teeth back at that time,” Levy said. “Many people couldn’t even serve in World War II because they didn’t have enough teeth that could bite together.”

According to the Centers for Disease Control and Prevention, or CDC, fluoridation trials began in 1945. The studies looked at four sister cities with similar population sizes, Hackett-Leas said, and found a 50 to 60 percent reduction in tooth decay in water systems that were fluoridated.

“[The results were] kind of coinciding with studies that they were doing with naturally occurring fluorides,” Hackett-Leas said.

In 1950, the U.S. Surgeon General strongly encouraged communities to proceed with adding fluoride to their water supply, according to the CDC. By 2012, fluoridated water was supplied to 74.6 percent of Americans, with 67.1 percent having access to fluoridated tap water.

How does fluoride impact public health?

Fluoridated water has many proven positive public health impacts, particularly impacting those without proper access to dental care.

“Sixty-seven percent of Iowans drink fluoridated water,” said Johnson County Public Health Director Danielle Pettit-Majewski. “Considering we are in a dental shortage area, and not a lot of places will take Medicaid, [fluoridated water] is a huge social safety net in terms of our dental health, especially for kiddos.”

Levy said underserved communities, in particular, need fluoridated water the most, as they do not always have proper access to professional oral health care.

“With community water fluoridation, there isn’t the need to be having a favorable family situation where maybe you can afford to go to the dentist, can afford to get fluoride treatments, can have toothbrushes and fluoride toothpaste for everybody,” he said.

Part of Hackett-Leas’ duties is to oversee and audit the kindergarten and ninth-grade requirements for school screens. The state of Iowa requires children entering both grades to be screened by a dentist and to report the results to the school.

When comparing two schools in Iowa County, Hackett-Leas said she saw a significant difference between the community with naturally occurring fluoride water and the community below the CDC threshold for optimal fluoride levels.

Hackett-Leas, Pettit-Majewski, and Levy all said direct measurement of fluoride’s benefits today is challenging, highlighting the lack of institutional memory of life before these public health measures.

“[Because] of the fact that nothing happens when you are doing public health in the way you should, people are thinking, ‘Oh, it’s not needed,’ but it’s just part of infrastructure,” Pettit-Majewski said. “You don’t think about the pipes right under your feet until your water doesn’t turn on.”

Hackett-Leas, Pettit-Majewski, and Levy also all touched on the cost-effectiveness of fluoride, mentioning that the return on investment is between $20 and $38 for every dollar invested, meaning water fluoridation saves the general public thousands of dollars per year in dental costs.

What would happen if fluoride was removed from water?

Although other sources of fluoride, such as fluoridated toothpaste and dental treatments, have become more common alongside water fluoridation, Levy said removing fluoride from water could lead to increases in cavity rates.

Levy cited a study published earlier this year from Israel, where they had stopped fluoridating due to political issues. The study compared different communities, finding that cavity rebound rates were twice as high as in other communities that were still fluoridating.

RELATED: Coralville proposes $3 million well project to boost water supply – The Daily Iowan

Pettit-Majewski said there would be both health and humane setbacks.

“When you think about our dental hygiene and our dental health impacts on our day-to-day life, I think people don’t always think about how much your smile impacts how people perceive you,” she said. “Whether it’s getting a job, getting a date, or whether it’s just how people treat you.”

In addition to the cost fluoride saves the general public, Pettit-Majewski cited worries about lost days of school, education, and nutrition.

Are there any proven negative effects of fluoride?

Levy debunked claims about some of the negative effects of having fluoride in water.

“There were claims of generalized cancer rates being much higher in fluoridated areas, which when the National Cancer Institute did some very nicely controlled studies, [they] determined it was due to the industrialization in those communities,” he said.

Fluoride is a “bone seeker,” targeting the teeth and bones in our skeletal systems. Despite worries that fluoride makes bones weaker, Levy said this only happens when there are high levels above four parts per million in the skeletal system. The CDC’s optimal rate is set at 0.7 parts per million.

“Some of the best evidence there is shows no meaningful association [at optimal levels],” Levy said. “There is no concern for low to moderate levels of fluoride in the water.”

Levy also said that all previous studies done relating fluoride to lower IQ levels and neurodevelopment concerns were not well-controlled and could not be taken seriously from a scientific standpoint.