Hundreds of thousands of American children are drinking from tap water that may be lowering their IQs, according to a bombshell government report.
The paper — described as the most thorough of its kind — concluded that consuming high levels of fluoride can harm brain development in youngsters.
Researchers found drinking water with more than 1.5 milligrams of fluoride per liter was associated with a drop in IQ of up to five points.
The finding could be significant, given more than 1.9million people rely on water systems with fluoride levels above 1.5mg, the report said.
Based on an analysis of previously published research, the report marks the first time a federal agency has determined ‘with moderate confidence’ that there is a link between fluoride and IQ.
The above map shows estimated fluoride concentrations in community water systems between 2006 and 2011. It was published in 2023. Counties that are colored red have more than double the recommended level of fluoride in their water
Fluoride has been added to the US water supply for decades after studies showed it could strengthen teeth and reduce cavities — in what has long been considered one of the greatest public health achievements of the 20th century.
Estimates suggest that fluoridation saves $6.5billion every year in dental treatment costs, and reduces the occurrence of cavities by up to 25 percent — according to the CDC.
But the new report is likely to set off alarm bells in dozens of counties across Illinois, Texas, New Mexico, where research shows fluoride levels in water are particularly high.
Since 2015, the US has recommended that fluoride levels in drinking water do not exceed 0.7 milligrams per liter.
The Environmental Protection Agency says fluoride levels should not be above four milligrams per liter to avoid skeletal fluorosis, a potentially crippling disorder causing weaker bones, stiffness and pain.
And the World Health Organization says the safe limit is about 1.5 milligrams of fluoride per liter.
Experts say fluoride easily enters the blood when it is consumed, and can then travel to the brain.
Previous studies in animals have shown that fluoride can impact neurochemistry in areas of the brain linked to learning, memory, executive function and behavior.
The new, 324-page Government report comes from the National Toxicology Program, part of the Department of Health and Human Services.
Some of the studies reviewed in the report suggested IQ was 2 to 5 points lower in children who’d had higher exposures.
The team did not reach a conclusion on fluoride’s impact at lower doses or its effect on adults.
There has been controversy over fluoride in the water supply for years, with hundreds of communities voting against its use (Above is a campaign sign from Kennebunk, Maine)
The report adds to previous evidence suggesting fluoride is linked to anxiety, temper problems and headaches in children as young as three.
And previous research suggested that pregnant women should limit their fluoride exposure because the mineral can cross the placenta and reach the fetus.
The new report summarized research from Canada, China, India, Iran, Pakistan and Mexico.
It concluded that drinking water containing more than 1.5 milligrams of fluoride per liter was associated with a lower IQ in children.
More than 1.9million people — or 0.6 percent of the US population — rely on water systems that contain naturally occurring fluoride levels above 1.5 milligrams per liter, according to the report.
It did not mention how many people are on water systems with fluoride artificially added where concentrations are above this level.
The above image shows a woman filling a glass of water from a tap, amid concerns over the quality of tap water (stock)
This map, from 2020, shows fluoride levels in untreated groundwater supplies. Fluoride is a naturally-occurring mineral and is often already present in many water supplies. Areas marked with a yellow or red dot have more than twice the level of fluoride in groundwater than recommended
Fluoride is a mineral that naturally occurs in water and soil.
But about 80 years ago, scientists discovered that people whose water supplies naturally had more fluoride also had fewer cavities. They determined it was replacing minerals in teeth that were lost in decay and wear.
This triggered a push to get more Americans to use fluoride, and to have the mineral added to national drinking water supplies.
Today, about 70 percent of US households have access to fluorinated drinking water.
This is much higher than in many comparable nations, including the UK (10 percent), Spain (10 percent) and Canada (40 percent).
The report comes as IQ scores in America drop for the first time in a century.
A study from the University of Oregon and Northwestern analyzed the results of nearly 400,000 IQ tests done between 2006 and 2018 — in a study published last year.
While they did not give an exact drop, they said the biggest decrease was in people aged 18 to 22 years and those who were less well-educated.
The study only used data from before the Covid pandemic, meaning disruptions to education caused by lockdowns may have worsened the situation further.
According to anti-fluoride group Fluoride Action Network, since 2010 more than 240 communities worldwide have removed fluoride from their drinking water.
Regina Barrett, 69, from a small city in North Carolina, is among the thousands of Americans who are not happy with fluoride in her drinking water.
‘Our water has been cloudy and bubbly and looks milky,’ said Ms Barrett, who blames fluoride for the issues according to KFF Health News. ‘I don’t want fluoride in my nothing!’
Far more counties in the US fluorinate their water than in any other country in the world, data from the National Population Review for the year 2024 reveals
The National Toxicology Program started to review the impact of fluoride in drinking water back in 2016.
There were earlier drafts, but the final report was repeatedly held up. At one point, a committee of experts said available research did not support an earlier draft’s conclusion.
The American Dental Association, which champions fluoride in water, was critical of earlier versions of the analysis — but is yet to comment on the new report.
Rick Woychik, the director of the program, said in a statement: ‘Since fluoride is such an important topic to the public and to public health officials, it was imperative that we made every effort to get the science right.’
Official limits were initially set to prevent skeletal fluorosis, but more and more studies have increasingly pointed to a link between higher fluoride levels and an impact on brain development.
Researchers have wondered about the impact on a developing fetus or very young children who might ingest water with baby formula.
The Fluoride Action Network heralded this week’s report as ‘landmark’ and said it proved what many researchers had long suspected.
