"Two studies — one from Canada and one Mexico — released today point to potential health problems from fluoride, which, in a majority of U.S. communities, is purposefully added to drinking water to protect people's teeth.
The Canada study found that adults who are iodine deficient and have higher levels of fluoride in their system have a greater risk of an underactive thyroid. The Mexico study found mothers with higher fluoride exposure during pregnancy were more likely to have children with symptoms of ADHD. Both studies were published in the journal Environmental International.
A third study, published in Environmental Health Perspectives, found that among 1,566 pregnant women in Canada, fluoride levels in urine were almost two times higher for women who lived in regions where the element was added to their drinking water compared to pregnant women in regions with non-fluoridated water."