Hey teda,
Had a look through 'google scholar' and found research about how fluoride isn't so great for thyroid function .. well certainly not good in mice and cattle which is of course a good warning to us humans to be very careful with its use.

Keep in mind that these animals are probably receiving roughly 200 to 500 times more fluoride than is normally in our water supplies (the rodents in the article below received 0.5g/L, which is 500ppm fluoride, and I think we normally get about 1ppm fluoride, according to wikipedia). so to put that in perspective, how healthy would I be if my mother drank 500 times more alcohol than is normal whilst pregnant, or consumed 500 times more caffeine than the normal population..

* Some worrying research on fluoride. Pregnant rodents are fed a large amount of fluoride
http://www.fluoride-journal.com/01-34-3/343-165.pdf

* Unit conversions
http://www.simetric.co.uk/si_ppm.htm

what I can eat on the diet (click here) -- my blog -- contact me (PM is broken)
"Some men, in truth, live that they may eat, as the irrational creatures, 'whose life is their belly, and nothing else.' But the Instructor enjoins us to eat that we may live." -- Clement of Alexandria (about 200 AD)