According to a new U.S. government report, fluoride in drinking water can be linked to lower IQ in children when it is found at twice the recommended limit. Researchers with the Department of Health and Human Services analyzed previously published research and said they determined “with moderate confidence” that there is a link between higher levels of fluoride exposure and lower IQ in kids.
Fluoride strengthens teeth and reduces cavities by replacing minerals lost during normal wear and tear. Adding low levels of fluoride to drinking water is considered one of the most impactful public health achievements of the last century.
After studying reports from six different countries, HHS researchers found drinking water that has more than 1.5 milligrams of fluoride per liter can be consistently linked to lower IQs in kids. However, the report did not say how big an impact it has on IQ.
Some of the studies reviewed in the report suggested kids who had higher exposure to fluoride had IQs two-five points lower than their peers.
Since 2015, U.S. health officials have recommended a fluoridation level of 0.7 milligrams per liter of water but for five decades before that, the recommended upper range was 1.2. The World Health Organization considers 1.5 milligrams of fluoride per liter of drinking water as the safe limit.
The report shows less than half of 1% (0.6%) of the U.S. population are on water systems with naturally occurring fluoride levels higher than the recommended limit. Still, that amounts to about 1.9 million people.
Adding fluoride to drinking water has long been a controversial topic. While many hail its dental benefits, others worry about its potential health effects.
