Fluoride Found to Have No Effect on Cognitive Learning

Dentistry Today


The federal National Toxicology Program (NTP) has found no link between elevated levels of fluoride and cognitive learning deficits. In nine tests conducted on rats that consumed food and water with varying fluoride levels, NTP researchers observed no exposure-related differences in motor, sensory, or learning and memory performance or in thyroid hormone levels. 

From their prenatal development through their adulthood, the rats consumed water with 0, 10, and 20 ppm concentrations of fluoride. They also consumed food with 20.5 ppm (standard diet) and 3.24 ppm of fluoride. The only side effect was inflammation of the prostate gland, which was observed only at an exposure far above the level of what’s typically in fluoridated water.

The Centers for Disease Control and Prevention (CDC), the World Health Organization, the ADA, and other groups recognize the benefits of adding fluoride to toothpaste and drinking water. The CDC also notes that 74.4% of people in the United States who use community water systems drink fluoridated water.

Many activists contend that fluoridation is ineffective, harmful, and an infringement on individual freedoms. One group, the Fluoride Action Network, heralded the announcement of the study’s launch, citing the NTP’s “cutting edge scientific tools” and anticipating that it would “end fluoridation.” 

“Critics of community water fluoridation were thrilled when the NTP said they would conduct a thorough study of this issue,” said Johnny Johnson Jr, DMD, MS, president of the American Fluoridation Society. “However, they have been as quiet as a church mouse since the NTP’s findings were made public. Once again, they choose to ignore the studies that don’t fit into their fear-based mindset. They’re choosing silence over science.” 

In addition to the NTP study, a 2015 study in New Zealand found no link between fluoridation and IQ scores over a 31-year period. A Public Health England report released in March found that “fluoridation is an effective and safe public health measure to reduce the severity and frequency of dental decay.” Last month, the Food Safety Authority of Ireland issued a report stating that there was “no scientific basis for concerns about the safety of children or adults” due to fluoride exposure from foods and drinks.

The study, “An Evaluation of Neurotoxicity Following Fluoride Exposure from Gestational Through Adult Ages in Long-Evans Hooded Rats,” was published by Neurotoxicity Research.

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