Drink this in.
New research challenges recent claims about the risks of fluoride in drinking water, reporting that in addition to preventing cavities, the additive may actually improve test scores.
A 2024 report from the federal National Toxicology Program determined with “moderate confidence” that higher levels of fluoride are associated with lower IQ scores.
Those findings sparked uproar, as the studies that inspired the report primarily focused on countries with far higher levels of fluoride than considered safe in the US.
That review did not ascertain whether the current recommended low fluoride level of 0.7 milligrams per liter for US community water supplies harms children’s IQ.
The new study, published in the journal Science Advances, focused on US-recommended levels of fluoride. It found “robust evidence” that young people exposed to low levels of fluoride in their drinking water performed better on cognitive tests than those not exposed.
Motivated by the “shocking” findings in the 2024 report, lead author Dr. Rob Warren said he was driven to deliver more relevant research.
“I wouldn’t have done this work had it not been an empirical question that I didn’t think we had an answer to, of great immediate policy interest,” Warren, a sociology professor at the University of Minnesota, told CNN.
Warren said the results in the 2024 report are misleading.
“Imagine testing some new drug for heart disease, and the recommended dosage is 100 milligrams, and then your study compares people who get a million milligrams to people who get half a million milligrams,” he added. “Well, that doesn’t tell you anything about the effect of getting 100 milligrams versus getting nothing.”
Warren and his team explored the cognitive performance of nearly 27,000 people, along with their exposure to fluoride in community drinking water.
Since 2010, more than 170 communities across the country have chosen to remove fluoride from their drinking water.
Health and Human Services Secretary Robert F. Kennedy Jr. has openly criticized fluoride, calling it “industrial waste” and arguing that adding it to drinking water can harm brain development and bone health and cause other issues.
Earlier this year, Utah and Florida made history by becoming the first states to outlaw the addition of fluoride to public drinking water. Antifluoridation bills have also been introduced in states like North Dakota, Tennessee and Montana.
Warren’s study found that students exposed to fluoride for part of their childhood had higher high school test scores than those with no exposure, and the difference was even greater for those exposed throughout their childhood.
The team conducted follow-up tests through 2021 among participants aged 60 or older and found that fluoride exposure was not associated with cognitive decline in an aging population.
It is important to note that cognitive tests are not a direct measure of IQ.
There is a strong correlation, Warren told CNN, but cognitive tests are designed to assess mental functioning, such as reasoning, problem-solving and memory.
He’s working on research that will directly evaluate the relationship between fluoride exposure and IQ.
Fluoride is a naturally occurring mineral found in soil, water, plants and even many foods.
The practice of adding fluoride to US drinking water began in Grand Rapids, Michigan, in 1945 to reduce tooth decay. After 10 years, local dentists reported a jaw-dropping 60% reduction in cavities among children.
Research published earlier this year estimated that removing fluoride from US public water would, within five years, lead to 25.4 million additional decayed teeth in children and adolescents, along with $9.8 billion in health care costs.
While this latest study did not measure dental health, experts note that tooth decay and dental pain can cause children to struggle to concentrate and skip school, which may affect cognitive test scores.
