"Some recent studies suggest that over-consumption of fluoride can raise the risks of disorders affecting teeth, bones, the brain and the thyroid gland," reports Scientific American editors (January 2008). "Scientific attitudes toward fluoridation may be starting to shift," writes author Dan Fagin.
"Fluoride, the most consumed drug in the USA, is deliberately added to 2/3 of public water supplies theoretically to reduce tooth decay, but with no scientifically-valid evidence proving safety or effectiveness," says lawyer Paul Beeber, President, New York State Coalition Opposed to Fluoridation.
Fagin, award-wining environmental reporter and Director of New York University's Science, Health and Environmental Reporting Program, writes, "There is no universally accepted optimal level for daily intake of fluoride." Some researchers even wonder whether the 1 mg/L added into drinking water is too much, reports Fagin.
After 3 years of scrutinizing hundreds of studies, a National Research Council (NRC) committee "concluded that fluoride can subtly alter endocrine function, especially in the thyroid – the gland that produces hormones regulating growth and metabolism," reports Fagin.
Fagin quotes John Doull, professor emeritus of pharmacology and toxicology at the University of Kansas Medical Center, who chaired the NRC committee thusly, "The thyroid changes do worry me."
Fluoride in foods, beverages, medicines and dental products can result in fluoride over-consumption, visible in young children as dental fluorosis – white spotted, yellow, brown and/or pitted teeth. We can't normally see fluoride's effects to the rest of the body.
Reports Fagin, "a series of epidemiological studies in China have associated high fluoride exposures with lower IQ."
"(E)pidemiological studies and tests on lab animals suggest that high fluoride exposure increases the risk of bone fracture, especially in vulnerable populations such as the elderly and diabetics," writes Fagin.