A study released on August 21 from National Toxicology Program (NTP) on the effects of fluoride exposure on cognitive function concluded that fluoride levels in drinking water above 1.5 milligrams per liter are associated with lower IQ scores in children.
The NTP, part of the US Department of Health and Human Services, began its study in 2016 with all of its work undergoing rigorous scientific and peer review by the National Academies of Sciences, Engineering, and Medicine (NASEM) and experts from various federal health agencies.
NTP research found that for every additional 0.5 mg/L increase in fluoride exposure, there could be 2.5 fall in IQ. This inverse relationship was observed in various countries, indicating a global health concern. This relationship has been described as linear in some analyses, suggesting that there is no safe level of exposure when considering cognitive health.
Datasets included both human epidemiological studies and animal research, with an emphasis on neurodevelopmental outcomes. These studies were drawn from different geographic locations, ensuring a wide range of exposure levels and demographic backgrounds.
The NTP recommended a reassessment of fluoride levels in public water supplies. While not advocating an immediate end to water fluoridation, the program suggests that current guidelines may need to be adjusted to protect public health, particularly for vulnerable populations.
Children, especially at critical developmental stages, and fetuses are recognized as the most sensitive to the cognitive effects of fluoride. Prenatal exposure through maternal consumption has been linked to neurobehavioral deficits in offspring, highlighting the importance of monitoring fluoride intake during pregnancy. In addition, people who live in areas with naturally high levels of fluoride or where water is treated with higher than average fluoride concentrations face increased risks.
The NTP calls for further research to determine safer exposure limits and for public health policies to consider these cognitive risks alongside dental health benefits.
The main sources of fluoride exposure include:
- Drinking water: The most talked about and often the primary source, especially where fluoride is added for dental health or where natural levels are high.
- Dental products: Toothpaste, mouthwashes and fluoride treatments in dental offices.
- Food and drinks: Some foods and beverages, especially tea, can contain significant levels of fluoride due to soil and water content.
- Industrial exhibition: Some industries emit fluoride, which can contaminate local water supplies or the air.
According to the Water Quality Report 2023 by the Mukilteo Water and Wastewater District, fluoride is added to water for dental health. The average fluoride concentration in its water system is 0.7 parts per million (or 0.7 mg/L). The same fluoride levels were reported in 2023 Alderwood Water & Wastewater Report.
According to Snohomish PUD and Snohomish County Health Department documentation, fluoridated water is also added as a dental additive in the following communities at a concentration of 0.6-0.7 mg/L: Brier, Edmonds, Granite Falls, Lake Stevens, Mill Creek , Monroe Mountlake Terrace and Sultan.
Non-fluoridated drinking water is available in the communities of Darrington, Gold Bar, Lakewood, Maltby, Snohomish and Stanwood.
The release of the NTP study will likely reignite the debate over the use of fluoride in drinking water. While the study does not call for a complete ban on fluoridation, it strongly advocates for caution and further research into the cognitive effects of fluoride, especially in children. As the debate continues, the focus remains on balancing dental health benefits with potential cognitive risks.
