NEW YORK — A U.S. government report expected to spark controversy has concluded that having twice the recommended amount of fluoride in drinking water reduces children’s IQs.
The report, based on an analysis of previously published studies, is the first time a federal agency has determined, with “moderate confidence,” that there is a link between high fluoride exposure and lower IQ in children. Although the report was not prepared to assess solely the health effects of fluoride in drinking water, it is a startling acknowledgement of possible neurological risks from high levels of fluoride.
Fluoride strengthens teeth and reduces cavities Replenishes minerals lost through normal wear and tearAccording to the U.S. Centers for Disease Control and Prevention, adding low levels of fluoride to drinking water has long been considered one of the greatest public health achievements of the last century.
“I think this report is really important for understanding this risk,” said University of Florida researcher Ashley Mullin. Researched The report looked at how high fluoride levels in pregnant women can affect their children, and she called it the most rigorously conducted report of its kind.
Long-awaited Report The report, released Wednesday by the National Toxicology Program, part of the Department of Health and Human Services, summarized a review of studies conducted in Canada, China, India, Iran, Pakistan and Mexico and concluded that drinking water with more than 1.5 milligrams of fluoride per liter is consistently associated with lower IQ in children.
The report did not attempt to quantify exactly how much IQ declined at different levels of fluoride exposure, but some of the studies it reviewed suggested that children with higher exposure had IQs between two and five points lower.
Since 2015, federal health officials have recommended a fluoride level of 0.7 milligrams per liter of water, up from a recommended upper limit of 1.2 for the previous 50 years. The World Health Organization has set the safe limit for fluoride in drinking water at 1.5.
According to the report, about 0.6 percent of the U.S. population, or about 1.9 million people, have water with natural fluoride levels of 1.5 milligrams or more.
“The findings of this report raise questions about how we can best protect these people and what makes the most sense,” Marin said.
The 324-page report was inconclusive about the risks posed by low levels of fluoride, saying more research was needed, and did not answer questions about how high levels of fluoride might affect adults.
The American Dental Association, which advocates for water fluoridation, had criticized earlier versions of the new analysis and Mullin’s study. Asked for comment, a spokesman for the association said in an email late Wednesday afternoon that its experts were still reviewing the report.
Fluoride is a mineral that occurs naturally in water and soil. Nearly 80 years ago, scientists discovered that people with more natural fluoride in their bodies had fewer cavities, encouraging more Americans to use fluoride for dental health.
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board member Lowered The 2015 recommendations on fluoride levels in drinking water were issued to combat dental fluorosis, a condition that causes tooth spots to appear and is becoming more common among U.S. children.
Meanwhile, the Environmental Protection Agency maintains its long-standing requirement that water systems must not contain more than 4 milligrams of fluoride per liter, a standard intended to prevent skeletal fluorosis, a disorder that can cause bones to become weak, stiff and painful.
But a growing body of research points to another problem, suggesting a link between high levels of fluoride and brain development. Researchers have wondered about its effects on developing fetuses and young children who may ingest water with formula. Animal studies have shown that fluoride can affect neurochemical cell function in areas of the brain responsible for learning, memory, executive function and behavior.
In 2006, the National Research Council, a private nonprofit organization in Washington, DC, said limited evidence from China indicated neurological effects in people exposed to high levels of fluoride and called for more research into fluoride’s effects on intelligence.
As further research continued to raise questions, in 2016 the National Toxicology Program began working on a review of existing research that could guide whether new fluoride restriction measures were needed.
There have been previous drafts, but the final document has been delayed many times, with an expert committee at one point saying that available research did not support the conclusions of earlier drafts.
“Because fluoride is such an important issue to the public and public health officials, it was essential that we make every effort to obtain scientifically sound information,” Rick Wojcik, director of the National Toxicology Program, said in a statement.
Mullin said it would make sense for pregnant women to reduce their fluoride intake from certain types of tea as well as water. It might also be reasonable to have a policy discussion about whether to require fluoride content to be listed on beverage labels, Mullin said.
