Fluoridation Is at a Crossroads
The controversy around adding fluoride to drinking water was recently highlighted by an article in the Wall Street Journal, which addressed its possible negative neurological effects on children.1 The article cited recent studies on what levels of fluoride are needed to protect teeth without risking possible cognitive harm to prenatal children and infants. It detailed a paper in JAMA Network Open that discussed the possible association of higher maternal prenatal and early post-natal fluoride levels and neurotoxicity.2 The authors measured fluoride levels in the urine of pregnant women in Los Angeles County. They found those with high levels were more likely to have children who exhibited neurobehavioral problems than those whose mothers had lower levels of fluoride. The authors stated that there was not necessarily a cause and effect to their findings, but still questioned if the current levels of supplementation should be lowered.
Additional information on the topic has been published by the National Toxicology Program, a government organization that assesses potentially toxic chemicals. It has moderate confidence that higher levels of fluoride exposure are associated with lower IQ in children.3 High levels were defined as 1.5 mg of fluoride per liter, which is more than two times the United States recommended level of 0.7 milligrams per liter. In response to the Toxicology paper, the American Dental Association (ADA) stated that the information was not supported by scientific evidence.4
A number of communities across the US and Canada have stopped adding fluoride to drinking water. An example of the effect can be seen by comparing data on decay rates between Calgary and Edmonton Canada. Calgary stopped adding fluoride in 2011 while Edmonton continued supplementation. The WSJ article cited the results of an article that compared caries rates in children between the two cities. The study found a 65% higher decay rate in Calgary compared to Edmonton. Calgary has since resumed fluoridation.
Those who choose to limit their fluoride exposure can consume bottled water or use reverse osmosis filtration systems. To avoid the fluoride in water but offer some protection for decay the US Centers for Disease Control and Prevention currently recommends that children start fluoride toothpaste at age 2 initially using smaller amounts; this should also be safe for pregnant women.
In summary, the preponderance of available data indicate that the current levels of fluoride (0.7 milligrams per liter) in drinking water do not have negative neurological effects in children but they do reduce tooth decay. While the debate continues, hopefully future studies will provide more robust data that will allow the profession to protect our children from caries without the risk of neurologic problems.
References
- Reddy S. What the science actually says about fluoride in drinking water. Wall Street Journal. December, 18, 2024.
- Malin AJ, Eckel SP, Hu H, et al. Maternal urinary fluoride and child neurobehavior at age 36 months. JAMA Netw Open. 2024;7:e2411987.
- National Toxicology Program (NTP). NTP Monograph on the State of the Science Concerning Fluoride Exposure and Neurodevelopment and Cognition: a Systematic Review. Research Triangle Park, North Carolina: NTP Monograph 08; 2024.
- American Dental Association. Fluoride in Water. Available at ada.org/resources/community-initiatives/fluoride-in-water. Accessed May 6, 2025.
From Decisions in Dentistry. May/June 2025;11(3):6.
