Fluoride in drinking water draws growing scrutiny

By HPN Staff

A national re-examination of fluoridated water is well underway, with a number of localities and at least two states ending long-standing programs to add a bit of the mineral to their drinking water supplies.

Legislatures in Florida and Utah passed statewide bans earlier this year, and U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. has said he wants the federal government to end a decades-long recommendation to fluoridate water.

Multiple health groups oppose the change, including the American Academy of Pediatrics and the American Dental Association, which “unreservedly endorses the fluoridation of community water supplies as safe, effective and necessary in preventing tooth decay.”

Why it matters

Water fluoridation is widely credited for improving dental health in the United States, and the Centers for Disease Control and Prevention has long said that “studies continue to show that widespread community water fluoridation prevents cavities and saves money, both for families and the health care system.”

In fact, the CDC named community water fluoridation one of the 10 greatest public health achievements of the 20^th Century.

But Kennedy, a former environmental lawyer who has also pushed back on long-standing U.S. vaccine policies, said earlier this year that he planned to tell the CDC to stop recommending adding fluoride, which he has called “a dangerous neurotoxin.”

Multiple studies suggest a link between excess fluoride above government-recommended levels and poorer childhood brain development, and those concerns – along with the argument that individuals ought to decide their own fluoride intake – have buoyed the backlash.

The National Toxicology Program review “concluded, with moderate confidence, that higher levels of fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children.”

However, the researchers bolded a caveat in their report: “It is important to note that there were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children’s IQ.”

According to the CDC, 7 mg/L is equivalent to about “3 drops of water in a 55-gallon barrel.”

That study also found no evidence that fluoride exposure had a negative effect on adult brains, and the group called for more research “to better understand if there are health risks associated with low fluoride exposures.”

The bigger picture

Most water contains naturally occurring fluoride, and water systems often add the mineral to get up to .7mg/L level. In some places they remove fluoride to hit that target.

According to the National Conference of State Legislatures (NCSL), as of 2022 about 72% of municipal water systems in the U.S. provide fluoridated water, reaching more than half the U.S. population. Fluoride is also commonly added to toothpaste, and mouthwashes and other supplements are widely available. However, the FDA has initiated steps to remove concentrated ingestible fluoride prescription drug products for children from the market.

So far this year, the NCSL said, at least 12 state legislatures have introduced bills prohibiting fluoridation or repealing provisions requiring it in public water systems. 

When Florida Gov. Ron DeSantis signed his state’s bill, he said it was about letting people make their own decisions.

“Some of these people, they think that they know better for you than you do for yourself,” DeSantis said, according to the Tampa Bay Times. “They think because they have medical training, or they have this, that they should just be able to decree how we live our lives.”

This doesn’t mean there won’t be any fluoride in municipal water in the state. Naturally occurring fluoride may remain, the law just forbids water systems from adding it.

Additional details

According to the NCSL, as of May at least 12 states had laws mandating that communities above a certain population fluoridate their water: California, Delaware, Georgia, Illinois, Kentucky, Louisiana, Minnesota, Mississippi, Nebraska, Nevada, Ohio and South Dakota.

The NCSL also notes that Iowa enacted a law in 2021 requiring public water system operators to notify state officials and customers at least 90 days before changing its fluoridation process. Washington enacted a similar law in 2023.

Last year the Colorado legislature created a program to screen children in kindergarten and third grade to assess optimal fluoride levels for preventing tooth decay, the NCSL said.