According to the National Research Council (2006), “the consistency of the results [in fluoride/IQ studies] appears significant enough to warrant additional research on the effects of fluoride on intelligence.” Reduced IQ is not the only neurotoxic effect of fluoride. thesis, Luke has also shown in animal studies that fluoride reduces melatonin production and leads to an earlier onset of puberty (Luke 1997).
Studies have shown an association between fluoride exposure and impaired visual-spatial organization (Calderon 2000; Li 2004; Rocha-Amador 2009); while three other studies have found an association between prenatal fluoride exposure and fetal brain damage (Han 1989; Du 1992; Yu 1996). Studies by Jennifer Luke (2001) show that fluoride accumulates in the human pineal gland to very high levels. Consistent with Luke's findings, one of the earliest fluoridation trials in the U. (Schlesinger 1956) reported that on average young girls in the fluoridated community reached menstruation 5 months earlier than girls in the non-fluoridated community.
To put this finding in perspective, the Department of Health and Human Services (DHHS, 1991) has estimated that total fluoride exposure in fluoridated communities ranges from 1.6 to 6.6 mg/day.
This is a remarkable fact, particularly considering the rampant and increasing problem of hypothyroidism (underactive thyroid) in the United States and other fluoridated countries.
Babies and children excrete less fluoride from their kidneys and absorb up to 80% of ingested fluoride into their bones (Ekstrand 1994).
The concentration of fluoride in the bones increases over a lifetime (NRC 2006).
In the mid-20th century, fluoride was prescribed by a number of European doctors to reduce the activity of the thyroid gland for patients with hyperthyroidism (overactive thyroid) (Stecher 1960; Waldbott 1978).
According to a clinical study by Galletti and Joyet (1958), the thyroid function of hyperthyroid patients was reduced at just 2.3-4.5 mg per day of fluoride.Infant exposure to fluoridated water has been repeatedly found to be a major risk factor for developing dental fluorosis later in life (Marshall 2004; Hong 2006; Levy 2010).As a result, dental researchers have recommended that parents of newborns not use fluoridated water when reconstituting formula (Ekstrand 1996; Pendrys 1998; Fomon 2000; Brothwell 2003; Marshall 2004).These rats had changes to their kidneys and brains, an increased uptake of aluminum in the brain, and the formation of beta-amyloid deposits which are associated with Alzheimer's disease.There have been 24 studies from China, Iran, India and Mexico that show an association between fluoride exposure and reduced IQ.Advocates of fluoridation counter that these animal studies are invalid because high doses of fluoride were used.