FLUORIDE 31(2), 1998, pp 59 - 60	International Society for Fluoride Research	Table of Contents

Two recent reports^1,2 that raise further questions about the alleged safety of water fluoridation reveal significant and disturbing brain cell neurotoxicity from relatively low concentrations of aluminium fluoride and sodium fluoride in drinking water of rats. Abstracted and commented on at length in this issue of FLUORIDE (pages 89-99), these investigations demonstrate that long-term ingestion by rats of drinking water containing either 0.5 ppm aluminium fluoride (AlF₃), or 2.1 ppm sodium fluoride (NaF) causes readily detectible damage not only to neuronal brain cells and vasculature but also to glomerular kidney cells.

In one set of experiments the commonly recommended 1 ppm fluoride ion level used in water fluoridation was present in the drinking water along with 0.5 ppm aluminium ion (reported as " 0.5 ppm AlF₃" ), and in the other series the same 1 ppm fluoride concentration was derived from 2.1 ppm NaF. Both brain cell and kidney cell abnormalities differed between the AlF₃ and NaF groups. Compared to controls with Al derived from the diet, the Al levels in the brain tissue were more than doubled in the AlF₃ group but not quite doubled in the NaF group. Although the kidney tissue Al levels were also doubled in the AlF₃ group, they were about the same in the NaF group.

Other previous experiments with rats showed that the toxicity of 0.5 ppm AlF₃ in the drinking water, including severe deterioration in overall health, was significantly greater than at 5 or even 50 ppm AlF₃. The reason for this paradoxical concentration effect is obscure, as is the mechanism by which aluminium along with fluoride passes through hydrophobic membranes and enters cells of the brain and kidneys.

Considering the clear-cut character of these laboratory findings, it is surprising that such adverse effects have not been reported long before now. After many years of supposedly intensive research, the 50th anniversary of the beginning of water fluoridation in Grand rapids, Michigan, was celebrated on 25 January 1995 as an occasion for "justifiable pride".³ Even as recently as 1993 a National Research Council report of the US National Academy of Sciences concluded that the US Environmental Protection Agency's current Maximum Contaminant Level of 4 mg/L (4 ppm) for fluoride in drinking water was quite appropriate as an interim standard.⁴ This position was supported by a selective review of data concerning dental and skeletal fluorosis, bone fragility, genotoxicity, carcinogenicity, and fluoride effects on the renal, gastrointestinal, and immune systems. Not cited, however, were fluoride effects on the central nervous system, including clinical reports of cognitive impairment⁵ and findings of impaired intelligence in both animals⁶ and humans^7,8 related to fluoride.

The "ethical basis"^9,10 for adding fluoride to water supplies depends on the procedure being safe or at least having a highly favourable benefit/risk ratio. The new findings reviewed here, showing impaired brain function from fluoride in conjunction with aluminium, have clearly tipped the balance against fluoridation. If we keep in mind the ancient dictum primum non nocere, then the death knell for fluoridation has begun to toll.

Bruce Spittle, Dunedin School of Medicine
Albert W Burgstahler, University of Kansas

REFERENCES

1. Isaacson RL, Varner JA, Jensen KF. Toxin-induced blood vessel inclusions caused by the chronic administration of aluminum and sodium fluoride and their implications for dementia. Neuroprotective Agents. Annals of the New York Academy of Sciences 825 152-166 1997.
2. Varner JA, Jensen KF, Horvath W, Isaacson RL. Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity. Brain Research 784 284-298 1998.
3. Burt BA. AAPHD Symposium: Fluoride: how much of a good thing? Introduction to the symposium. Journal of Public Health Dentistry 55 37-38 1995.
4. Subcommittee on Health Effects of Ingested Fluoride. Committee on Toxicology, Board on Environmental Studies and Toxicology, Commission on Life Sciences, National Research Council. Health Effects of Ingested Fluoride. National Academy Press, Washington, DC 1993 pp 1-11.
5. Spittle B. Psychopharmacology of fluoride: a review. International Clinical Psychopharmacology 9 79-82 1994.
6. Mullenix PJ, Denbesten PK, Schunior A, Kernan WJ. Neurotoxicity of sodium fluoride in rats. Neurotoxicology and Teratology 17 169-177 1995.
7. Li XS, Zhi JL, Gao RO. Effect of fluoride exposure on intelligence in children. Fluoride 28 189-192 1995.
8. Zhao LB, Liang GH, Zhang DN, Wu XR. Effect of a high fluoride water supply on children's intelligence. Fluoride 29 190-192 1996.
9. Diesendorf M. How science can illuminate ethical debates: a case study on water fluoridation. Fluoride 28 87-104 1995.
10. Spittle B. The ethics of water fluoridation. Fluoride 28 57-60 1995.

 

XXIInd CONFERENCE OF THE INTERNATIONAL SOCIETY FOR FLUORIDE RESEARCH August 24-27, 1998 Best Western Lakeway Inn, 714 Lakeway Drive, Bellingham Washington 98226, USA Lodging for 1-2 persons: $69 and $85 per night, plus 7.8% local tax: Phone (USA) 360 671 1011, Fax (USA) 360 676 8519. Bellingham International Airport is about 35 minutes from Seattle by air. Buses also run from Seattle and from Vancouver in Canada. Conference registration fee of $300 includes reception, lunches, coffee breaks, abstract book and guided bus tours. Further information, and registration forms, can be obtained from: Professor Ming-Ho Yu, Huxley College of Environmental Studies, Western Washington University, Bellingham WA 98225-9181, USA. Phone (USA) 360 650 3676 Fax (USA) 360 650 7284

FLUORIDE 31(2), 1998 Editorial, pp 59 - 60	International Society for Fluoride Research
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