Stop fluoridation now: new research on fluoride's brain and thyroid toxicity

Townsend Letter for Doctors and Patients, April, 2005 by Gary Null, Martin Feldman

In an editorial in Fluoride, Bruce Spittle discusses biochemical studies that have identified mechanisms by which fluoride could affect brain functioning. He summarizes the research as such: Because fluoride can form a strong hydrogen bond with the amide group, the shape of enzymes may be altered and their activity reduced. Aluminofluoride complexes stimulate various guanine nucleotide binding proteins--called G proteins--which may "mimic or potentiate the action of numerous extracellular signals and significantly affect many cellular responses. Fluoride ions in the presence of trace amounts of aluminum are apparently able to act with powerful pharmacological effects." (46)

In one animal study, rats administered aluminum fluoride or sodium fluoride in water had increased levels of aluminum in the brain, neural injury and increased deposits of [beta]-amyloid protein in the brain. Similar deposits have been associated with Alzheimer's disease, according to a report in Chemical & Engineering News. The researchers stated that while the small amount of fluoroaluminum complex needed to produce neurotoxic effects was surprising, "perhaps even more surprising" was the amount of sodium fluoride needed--2.1 ppm. (47,48) Another set of experiments found that rats given aluminum fluoride or sodium fluoride in drinking water had occlusions in the blood vessels. In the animals administered aluminum fluoride, the occlusions reduced cerebral blood flow and aerobic metabolism. There was a reduced number of cells in two areas of the hippocampus and changes in neurofilaments in the neocortex that are "usually considered to be related to cell dysfunction." (49)

Effects on the thyroid mechanism

The interaction between fluoride and iodine also has been the subject of research, with studies finding effects on both the thyroid system and the brain. The data in this area, on fluoride alone or the fluoride/iodine relationship, include:

* In a study of 7- to 14-year-olds in China, those in a high-fluoride, low-iodine area had an average IQ of 71, compared with 77 in a normal-fluoride, low-iodine area and 96 in a normal-fluoride, normal-iodine area. Thyroid effects in children in the high-fluoride, low-iodine area included a TSH of 21 mU/ml (compared with 6 in the normal area), a reverse T3 value of 58 ng/dl (21 in the normal area), and a significantly low reverse T3/T3 ratio of 2.91. IQ and TSH were negatively correlated in the study, and 69% of the children with mental retardation had elevated TSH levels. (50)

* An examination of 165 workers in electrolysis shops of aluminum production with signs of fluoride toxicity also had the following thyroid abnormalities: a moderate reduction in the iodine-absorbing function of the thyroid and a low level of T3 hormone with a normal level of T4 hormone. (51)

* A study of 200 children from areas with fluoride in the drinking water found an increase in serum parathyroid levels that was well correlated with fluoride ingestion. An increase in serum parathyroid concentration was associated with a greater severity of clinical and skeletal fluorosis. (52)