Fluoride Action Network

Fluoride Linked to Low IQ, Studies Show

Source: New York State Coalition Opposed to Fluoridation | August 25th, 2003
Location: International

Children’s intelligence declines as their natural drinking water fluoride levels increase, concluded a Chinese study in the May 2003 journal, “Fluoride.”

Children scored inferior IQ’s even when fluoride levels were similar to that added to U.S. water supplies to prevent tooth decay (1).

“As the fluoride levels in drinking water increased, the IQ fell and the rates of mental retardation and borderline intelligence increased,” write researchers Xiang, et al.

Tested were 512 children, aged 8-13 years from Wamiao, a high-fluoride village, and Xinhuai, a low-fluoride village. The high-fluoride village was divided into five subgroups by water fluoride levels, from 0.62 mg Fluoride per Liter to 4.38 mg F/L. As water fluoride levels increased within the high fluoride village, IQ decreased.

“When the data from the 512 children in the two villages were considered as a whole, a significant inverse correlation was found between IQ and the level of fluoride in urine,” the researchers report.

“These results are consistent with the findings recorded by Li at al. (3), Zhao et al. (4), and Lu et al. (5) of an inverse correlation between intelligence and dietary fluoride from either contaminated food or drinking water,” they report.

Neither village experiences coal burning pollution nor do residents drink brick tea, two common fluoride sources in China. Children with brain disease or head injury history were excluded. Only water fluoride levels differed between the two rural, low-income villages situated in the same province (Jiangsu) and county. Neither blood lead levels (2) nor urinary iodine differed between the test groups. The authors also controlled for family income and parental education

Fluoride crosses the blood-brain barrier producing biochemical and functional impairment of the nervous system during the developmental periods of infancy and childhood, the authors report.

“…despite growing evidence of serious neurotoxicity for both fluoride and lead, U.S. safety standards for fluoride in water have been moving in the opposite direction to those for lead in blood. From a scientific standpoint, this is very difficult to understand or to justify,” says organic chemist Albert Burgstahler, Ph.D., Editor, Fluoride (5a).

Chemistry Professor Paul Connett, Ph.D., presented (5b http://www.fluoridealert.org/nrc-paper.pdf ) and explained these and other fluoride adverse-effect studies, published since 1993, to the National Academy of Sciences’ National Research Council (NRC) panel studying “Toxicologic Risk of Fluoride in Drinking Water” (6) on 8/12/03. See power point presentation at http://www.fluoridealert.org/NRC-final.ppt . The NRC will recommend safe levels of fluoride in drinking water

“Two neurological studies are particularly important,” says Connett. “In 1995 Mullenix and colleagues (7) discovered fluoride gets into the brain, contrary to former beliefs. Then Varner and his team, in 1998, (8) found that even 1 part per million fluoride, the amount purposely added to U.S. water supplies, facilitated uptake of aluminum into rats’ brains causing amyloid deposits similar to Alzheimer’s patients,” says Connett.

The American Dental Association (ADA), a union that represents dentists’ interests, told the NRC panel “… the ADA urges the subcommittee to support retaining the current (1993) regulations…Since that time, there has been no published scientific evidence that should change those conclusions,” according to the ADA news. (9)

“Contrary to the ADA’s assurances of fluoridation‘s safety, the ADA is disregarding new adverse fluoride studies,” says Attorney Paul Beeber, President, New York State Coalition Opposed to Fluoridation. “The ADA can’t be relied on by the media, legislators, health officials and the public about fluoride and fluoridation’s safety or bodily effects,” says Beeber.


1) “Effect of Fluoride in Drinking Water on Children’s Intelligence,” Fluoride, Xiang et al., May 2003

2) “Blood Lead of Children in Wamiao-Xinhuai Intelligence Study,” letter Fluoride Xiang et al, August 2003

3) Li et al., “Effect of excessive fluoride intake on mental work capacity of children and preliminary study of its mechanism,” J West China University of Medical Sciences 1994; 25:188-9

4) Zhao LB, et al., “Effect of a high fluoride water supply on children’s intelligence, Fluoride 1996;29:190-2

5) Lu Y. et al., Fluoride Vol. 33 No. 2 74-78 2000 “Effect of High-Fluoride Water on Intelligence in Children”

5a) Editorial, Fluoride Vol. 35 No. 2 79-81 2003, by Albert W. Burgstahler, Editor

5b) Paul Connett’s presentation to the NRC

6) Toxicologic Risk of Fluoride in Drinking Water

7) Mullenix, PJ, et al, “Neurotoxicity of sodium fluoride in rats,” Neurotoxicity and Teratology, 1995;17:169-72

8) Varner JA, et al., “Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity,” Brain Res. 1998 Feb

(9) ADA NEWS, “Association urges NAS review panel to support current EPA fluoride practices, by Craig Palmer, posted August 14, 2003