Report: High Fluoride Levels Linked to Lower IQ in Children Here's how to find out how much fluoride is in your tap water
A report found that nearly two million Americans are regularly exposed to fluoride levels in water that have been linked to lower IQ in children
Kseniya Ovchinnikova / Getty Images
- A new report found that drinking water with fluoride levels above 1.5 mg/L has been linked to lower IQ in children.
- Nearly two million Americans have tap water that contains more than twice the amount of fluoride thought to be safe by the U.S. government, 0.7 mg/L.
- Experts say contacting your local water utility company or public utilities office is the best way to know how much fluoride is in your water.
Fluoride is oftentimes added to communities’ water supply to help residents ward off cavities, but a new report found that too much fluoride could be dangerous for kids’ health.
An August report by the National Toxicology Program (NTP) at the Department of Health and Human Services (HHS) found that lower IQ in kids has been linked to drinking water with fluoride levels two times higher than what the HHS deems safe.
An estimated 1.9 million Americans are living in communities with water fluoride levels at or above 1.5 milligrams per liter (mg/L). The HHS Public Health Service recommends that communities’ water supply have no more than 0.7 mg/L of fluoride.
This latest NTP report looked at a body of research done on exposure to fluoride in water since the practice began in the United States in the 1940s. They concluded a “moderate confidence” in evidence showing a link between lower IQ in children and elevated fluoride levels. However, fluoride levels don’t appear to have a negative effect on adult cognition.
“This is the first report of its kind from a government agency to make a determination about whether fluoride exposure can reduce child IQ,” Ashley Malin, PhD, assistant professor of epidemiology at the University of Florida College of Public Health and Health Professions, told Health.
Despite the report’s novel conclusions, experts stressed more research is needed.
“The question remains: at what exposure [is fluoride dangerous], and what are the policy recommendations?” added Howard Hu, MD, MPH, ScD, professor of preventive medicine in the Department of Population and Public Health Sciences at the University of Southern California Keck School of Medicine.
Here’s what experts had to say about how much fluoride Americans are exposed to, why the mineral could be toxic for children, and how to figure out if the fluoride levels in your water are safe.
Adding Fluoride to Water Puts Certain Communities at Risk
Fluorides are naturally occurring compounds that, in low doses, can help replace minerals that teeth lose over time, preventing cavities. Because of this, fluoride has been added to water for decades and can be found in products such as toothpaste and mouth rinses.
However, the practice of fluoridating water has long been controversial and has drawn both sharp criticism and support.
At high levels, fluoride exposure has been linked to tooth and bone damage. Plus, as the new NTP report acknowledges, there’s mounting evidence that the mineral could have some neurotoxic effects.
Most of the studies included in the new report were conducted in countries outside the U.S., such as Canada, China, India, Iran, Pakistan, and Mexico, where people were exposed to fluoride levels above the 1.5 mg/L limit deemed safe by the WHO. In the U.S., the government recommends a level of less than half that—0.7 mg/L.
However, fluoride occurs naturally in the soil, water, and air, meaning certain U.S. communities—nearly 2 million people—have water that naturally contains more than 1.5 mg/L of fluoride. One million people have tap water naturally fluoridated at 2 mg/L.
Even in communities where the fluoride levels in the water are lower, "additional exposure to fluoride from other sources" could pose a risk, Malin added.
Though the new NTP report sheds light on the connection between IQ issues and fluoride levels above 1.5 mg/L, experts agree there are significant questions left unanswered. In particular, it’s unclear at what specific level of exposure fluoridated water becomes dangerous for children and pregnant people.
“The NTP report does not adequately address this issue,” Tommaso Filippini, MD, DrPH, PhD, associate professor of epidemiology and public health at the Medical School of the University of Modena, Reggio Emilia in Italy, told Health.
A 2023 meta-analysis, which Filippini co-authored, included 30 studies on fluoride exposure in drinking water from around the world. It concluded that fluoride levels begin to impact kids’ IQ once they surpass 1 mg/L and become more pronounced at 2 mg/L.
Additionally, adults don’t seem to be at risk of cognitive issues from fluoride, “but there hasn’t been that much research done” on the subject, Hu told Health.
The Connection Between Fluoride and IQ in Children
According to Filippini, fluoride can accumulate in the regions of the brain responsible for memory and learning, creating oxidative stress in these parts of the brain. This stress could potentially lead to cell death.
The blood-brain barrier can protect adult brains from toxins to a certain extent, “but it is less efficient in the fetus during pregnancy and in children,” he added.
Some studies have shown that fluoride can cross the placenta and alter the developing brain, specifically in regions associated with learning, behavior, memory, and executive function, Malin added. Fluoride may also interfere with molecular processes involved in neurotransmission when the brain is developing, said Hu.
Hu said the evidence clearly shows fluoride is a neurotoxin, at least for a developing brain. But taking fluoride out of public drinking water entirely isn’t a great solution, he explained.
“There certainly are some communities of people who have less access to fluoridated products,” he said. “And you always worry that by adopting one society-wide practice or ending another society-wide practice, there will be people who are adversely impacted.”
How Much Fluoride Is in Your Water?
To find out what the local fluoride levels are in your community, check the searchable database from the Centers for Disease Control and Prevention (CDC), which has general data on fluoride levels by county.
But the agency cautions that “the best source of information on fluoride levels in community water systems is your local water provider (utility).”
In fact, this is the only option for people living in states that do not report their fluoride numbers to the CDC: Arizona, Hawaii, Montana, New Jersey, New Mexico, New York, Ohio, South Dakota, Washington state, Washington D.C., and Wyoming.
Most cities and counties publish information about fluoride levels on their own websites, which people can find through a search engine or by calling their city or county public utilities office.
The conclusions of the new report shouldn’t be cause for panic, Hu said, noting that the current data is limited to pregnant people, infants, and children.
However, for people who do live in communities with elevated fluoride levels in their water, there’s currently a lack of good solutions to lower exposure.
People could opt for bottled water over tap water, but both Malin and Filippini said they wouldn’t recommend that practice—bottled water is a source of microplastics, which have been linked to a host of other health issues, as well as a source of other potentially toxic chemicals found in plastic.
“Reverse osmosis filters will remove most of the fluoride, but those can be costly and also remove beneficial minerals,” Malin said.
This story originally appeared on: Health News - Author:Kaitlin Sullivan
