Water flows from a fountain in Concord, New Hampshire, on Friday, January 7, 2011. AP Photo
A new U.S. government report has raised concerns about fluoride in drinking water, suggesting a potential link between high fluoride levels and lower IQs in children. This marks the first time a federal agency has made such a claim with moderate confidence, based on a review of existing research. The findings could spark significant debate about fluoride's role in public health.
Fluoride has been added to drinking water for decades, praised for its role in preventing tooth decay. The Centers for Disease Control and Prevention consider it one of the major public health achievements of the last century. However, this recent report from the National Toxicology Program, part of the Department of Health and Human Services, suggests that fluoride levels above the recommended limit may have unintended effects on cognitive development.
The report summarizes studies conducted in various countries including Canada, China, India, Iran, Pakistan, and Mexico. It found that drinking water with more than 1.5 milligrams of fluoride per litre was consistently linked to lower IQ levels in children. While the report did not specify exactly how many IQ points might be affected, some studies indicated a reduction of 2 to 5 points in children with higher fluoride exposure.
In the U.S., the recommended fluoride level for drinking water has been 0.7 milligrams per litre since 2015, down from the previous upper limit of 1.2 milligrams. The World Health Organization has set a safe limit of 1.5 milligrams per litre. The report reveals that about 0.6% of the U.S. population, or roughly 1.9 million people, are on water systems with naturally occurring fluoride levels above this threshold.
Despite these findings, the report did not address the risks associated with lower levels of fluoride or its impact on adults. It also emphasized that more research is needed to fully understand the implications of fluoride exposure on brain development and cognitive function.
The American Dental Association, a strong advocate for water fluoridation, has criticized earlier versions of the analysis and Malin’s research. The association's spokesperson indicated that they were still reviewing the new report.
Fluoride, a mineral found naturally in water and soil, was first added to drinking water in Grand Rapids, Michigan in 1945. The practice was endorsed nationwide in 1950 to combat tooth decay. Although fluoride is beneficial for dental health, concerns about its safety have been raised, particularly with its potential impact on children's cognitive development.
Studies have shown that high fluoride levels can cause dental fluorosis, which affects the appearance of teeth, and in severe cases, skeletal fluorosis, which impacts bone strength. Recent research has also suggested that excessive fluoride may affect brain development, prompting calls for further investigation.
The National Toxicology Program has been working on this review since 2016, and the final report has faced several delays. Rick Woychik, director of the National Toxicology Program, emphasized the importance of getting the science right due to fluoride's significant public health implications.
Ashley Malin, a researcher from the University of Florida, noted the report's importance in understanding the risks associated with fluoride. She suggested that pregnant women might consider reducing their fluoride intake and proposed discussions on including fluoride content on beverage labels.
