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Public Trust in Tap Water May Hinge on Fluoride Link to Child IQ

Nov. 6, 2019, 9:58 PM

A federal agency’s preliminary finding that high concentrations of fluoride may decrease children’s IQ will, if finalized, be hard to explain to the public, scientists said Nov. 6.

The National Toxicology Program’s (NTP) draft report concludes that “fluoride is presumed to be a cognitive neurodevelopmental hazard to humans,” Seun Ajiboye, director of science policy and government affairs at the American Association for Dental Research, told a National Academies panel.

The public and media will focus on that “sensational” sentence, Ajiboye said.

Few people will read the report’s other finding: It’s unclear whether the mineral would harm children drinking typical concentrations of fluoride added to drinking water to help tooth decay, she said.

The report’s conclusions, however, “will likely influence the decision of local governments to fluoridate their water supplies, public support for fluoridation, and how safe people feel drinking tap water,” Ajiboye said.

“Community water fluoridation is considered one of 10 great public health achievements of the 20th Century, and is responsible for the substantial decline in tooth decay since its inception,” and those health benefits should be recognized in the toxicology programs report, she said.

Hazard Versus Risk

Ajiboye was among several scientists and others who spoke to scientists serving on a National Academies of Sciences, Engineering, and Medicine committee.

The panel held its first meeting Nov. 6 to launch its scientific review of NTP’s draft “Monograph on Systematic Review of Fluoride Exposure and Neurodevelopmental and Cognitive Health Effects.”

The National Toxicology Program will revise its fluoride report following the scientific critique and in light of other comments it receives, Mary S. Wolfe, deputy division director for policy at the program, told the committee.

The toxicology program wants the committee’s advice on issues including how best to communicate whatever final conclusions the agency reaches, John R. Bucher, NTP’s deputy division director for analysis, told the panel.

“It is a challenge to communicate that hazard is not the same thing as risk,” he said.

Hazard means something, perhaps a shark, has the potential to harm. Risk describes the probability that harm would occur. A shark poses no risk to someone in a desert, and great risk if it’s near a swimmer.

Risk Greater Than Recognized

Fluoride poses a greater risk than NTP’s draft report suggests, Chris Neurath, research director for the Fluoride Action Network, told the committee.

NTP’s report consistently paid less attention to studies that found low concentrations of fluoride could be harmful, he said.

The scientific evidence showing fluoride can harm children’s developing brains is as strong or stronger than was the data that emerged in the 1990s—and faced fierce criticism—showing low levels of lead were neurotoxic, Neurath said.

It took two decades for public health officials to accept that at a low level lead was indeed neurotoxic. “Millions of children suffered loss of IQ and behavioral problems during those two decades of critical indecision,” he said.

The academies should pay heed, he said.

“Fluoride is not lead,” said Ajiboye.

To contact the reporter on this story: Pat Rizzuto in Washington at

To contact the editors responsible for this story: Gregory Henderson at; Renee Schoof at; Rob Tricchinelli at