Drinking fluoride-treated water may lower children’s IQ, according to a major review that draws on a growing body of research.
The new research analyzed 74 other studies exploring how the mineral affects children’s brain development.
It found a strong association between higher levels of fluoride in tap water and lower IQ scores: for every small increase in fluoride found in children’s urine, there was a decrease of 1.63 IQ points.
The researchers said that while this may seem like a relatively small drop in IQ, “research on other neurotoxicants has shown that subtle changes in IQ at the population level can affect people in the high ranges and of the IQ distribution of the population.
They continue: “To put it in context, a five-point decrease in a population’s IQ would almost double the number of people classified as intellectually disabled.”
It comes after a US government report found hundreds of thousands of American children are drinking tap water that may be lowering their IQ.
Robert F Kennedy Junior, who has been named head of Health and Human Services (HHS), has signaled that he plans to eliminate fluoride from American drinking water because of these concerns. But there is debate about whether the risks would outweigh the benefits.
Fluoride has been added to the U.S. water supply for decades to strengthen teeth and reduce cavities, in what has long been considered one of the greatest public health achievements of the 20th century.
A major study has found that fluoride in drinking water can lower a child’s IQ and could “double the number of people classified as intellectually disabled.”
The above shows the most recently known fluoride levels in U.S. county water systems.
Estimates suggest that fluoridation saves $6.5 billion each year in dental treatment costs and reduces the occurrence of cavities by up to 25 percent, according to the CDC.
The U.S. Environmental Protection Agency (EPA) says fluoride levels should not exceed 4 mg/L in water, warning that any higher level increases the risk of skeletal fluorosis or skeletal deformities.
However, in recent years there has been a growing wave of research showing that water fluoridation can have some terribly dangerous side effects, particularly for children’s brains.
In the new meta-analysis, researchers led by Kyla Taylor of the National Institute of Environmental Health Sciences reviewed 74 studies from around the world on the link between fluoride and IQ.
The studies were conducted in China, Canada, Denmark, India, Iran, Mexico, New Zealand, Pakistan, Spain and Taiwan.
In a study in Mexico, children’s IQ scores dropped to 7.22 after exposure to fluoride.
Based on the findings, the authors say this risk should not be ignored and that more research into the impact of fluoride on the developing brain is warranted.
Researchers note that water and water-based beverages are the main source of systemic fluoride intake.
They also highlight that there are areas of the US where the quantities exceed the recommendations.
They write: ‘Of note, there are regions of the United States where community water systems and private wells contain natural fluoride concentrations greater than 1.5 mg/L,120 serving more than 2.9 million US residents. .
‘In addition, the US Geological Survey estimates that 172,000 US residents are served by domestic wells that exceed the applicable EPA standard of 4.0 mg/L fluoride in drinking water, and 522,000 are served from domestic wells that exceed the EPA’s non-applicable standard of 2.0 mg/L. mg/L of fluoride in drinking water.’
To reduce the risk of moderate to severe dental fluorosis, CDC recommends that parents use an alternative source of water for children eight years of age and younger and for bottle-fed infants if their primary drinking water contains more than 2 mg/L of fluoride. .
In the US, the Centers for Disease Control and Prevention (CDC) estimates that water and processed beverages (e.g., soda and juice) provide about 75 percent of a person’s fluoride intake. , and the EPA estimates that between 40 and 70 percent of a person’s fluoride intake comes from fluoridated drinking water.
However, an individual’s total exposure also reflects the contributions of fluoride in other sources, such as foods, dental products, industrial emissions, and pharmaceuticals.
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
A 2006 report from the National Research Council (NRC) concluded that high levels of naturally occurring fluoride in drinking water may be of concern for its neurotoxic effects.
And since then studies have looked at how fluoride exposure can affect brain development.
The findings come just weeks after a top doctor urged pregnant and breastfeeding women to avoid drinking tap water containing fluoride because the mineral could damage the fetus’s brain.
Dr. Michael Greger, author of the How Not to Die series, said even parents who feed their children formula should avoid mixing it with fluoride-treated water, which he called a “presumed developmental neurotoxin.”
Speaking to DailyMail.com, she said: “Pregnant and lactating women and those with babies who have water mixed with infant formula should try to use unfluoridated water.”
His comments came days after a federal judge warned that fluoride, added to water systems to strengthen teeth and reduce cavities, posed an “unreasonable risk” to children’s brains.
Many more counties in the US fluoridate their water than in any other country in the world, National Population Review data for 2024 reveals.
And just a month after a 320-page government report found that fluoride in high concentrations could cause children’s IQs to drop by up to five points.
Experts say that when someone drinks water containing fluoride, the chemical enters the bloodstream and can then travel to the brain.
Hypotheses suggest that fluoride could interfere with the brain during development, causing children to have lower IQs.
It is also possible that it crosses the placental barrier and reaches the fetus, where it could also disrupt brain development.
Additionally, experts say it is possible for fluoride to enter breast milk and be transferred to the baby.
Dr. Greger said it was also possible that fluoride was affecting brain health in adults, but more studies were needed to determine this.