A comprehensive nine-year review by the National Toxicology Program (NTP) has found a correlation between increased fluoride exposure and reduced intelligence in children. The study indicates that for every 1 milligram per liter (mg/L) increase in urinary fluoride levels, there is an associated decrease of approximately 1.63 IQ points in children.
While a single IQ point reduction may appear minimal, the study’s authors emphasize that, on a population level, such a decline could significantly increase the number of individuals classified as intellectually disabled.
The NTP’s findings have prompted legal and regulatory actions. In September, a federal judge ordered the U.S. Environmental Protection Agency (EPA) to reassess fluoride regulations to safeguard children’s intellectual development. Judge Edward Chen stated that the risk to health at exposure levels in U.S. drinking water is sufficiently high to warrant regulatory response by the EPA.
Fluoride, a naturally occurring mineral, has been added to public water supplies for decades to prevent tooth decay, following recommendations from health authorities like the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). However, excessive fluoride exposure has been linked to dental fluorosis, a condition causing streaks and spots on teeth. In 2015, the U.S. Department of Health and Human Services (HHS) adjusted its recommended fluoride levels in drinking water to 0.7 mg/L to prevent fluorosis.
The NTP’s review has led environmental health experts to call for a reassessment of fluoride’s risks and benefits, particularly concerning its potential neurotoxic effects on children’s developing brains. The CDC continues to endorse water fluoridation as a significant public health achievement, citing its role in reducing cavities. Nonetheless, the emerging evidence suggests a need for a balanced evaluation of fluoride exposure to ensure both dental health benefits and neurological safety.