The analysis revealed a statistically significant association between higher fluoride exposure and lower IQ levels in children. According to Kyla Taylor, the study's lead author and a health scientist at the National Institute of Environmental Health Sciences, for every small increase in fluoride levels detected in children’s urine, IQ scores dropped by an average of 1.63 points.

Most of the reviewed studies were conducted in countries outside the United States, such as China, where fluoride concentrations in drinking water are often higher than in the U.S. However, the researchers caution that their findings primarily stem from low-quality studies, limiting the ability to draw definitive conclusions.

Despite the study’s alarming implications, the researchers stopped short of calling for fluoride removal from public water supplies. Instead, they emphasised the need for further research into the potential neurotoxicity of fluoride, particularly in regions with high exposure levels.

Fluoride has been a cornerstone of public health efforts to reduce tooth decay since its introduction to drinking water in the United States in the mid-20th century. Major health organizations, including the Centers for Disease Control and Prevention (CDC) and the American Dental Association (ADA), endorse its use as safe and effective.

Dr. Erica Caffrey, a pediatric dentist and chair of the American Academy of Pediatric Dentistry’s Council on Clinical Affairs, warned of the potential consequences of reducing fluoride levels in water. “In communities where fluoride has been removed, we’ve observed significant increases in dental decay rates,” she noted.

Steven Levy, a preventive dentistry professor at the University of Iowa, expressed scepticism about the study’s findings. In an editorial accompanying the research, Levy argued that the evidence supporting fluoride’s cognitive impact at current exposure levels is weak. “The benefits of water fluoridation far outweigh the risks indicated by these flawed analyses,” he asserted.

While fluoride has proven benefits in preventing tooth decay, some experts believe the potential link to neurotoxicity in children warrants closer examination. Dr Bruce Lanphear, a health sciences professor at Simon Fraser University, called for the creation of an independent scientific panel to evaluate the evidence.

Taylor, the study’s author, acknowledged that the data are insufficient to determine whether fluoride concentrations at U.S. recommended levels—0.7 mg/L—impact children’s IQs. However, ongoing research may shed more light on the subject. For instance, researchers at the University of North Carolina are conducting a long-term study to observe cognitive development in children exposed to fluoridated and non-fluoridated water.

The controversy over fluoride is not new, but the study adds fuel to an already polarized debate. Critics, including Robert F. Kennedy Jr., have cited unproven claims linking fluoride to a range of health issues, from bone cancer to cognitive decline. On the other hand, proponents of fluoridation argue that removing it from public water supplies could reverse decades of progress in oral health.

As the debate continues, the findings underscore the need for balanced discourse and further scientific inquiry. While fluoride remains a vital tool for preventing tooth decay, understanding its broader health implications is essential to ensure informed decision-making for future generations.