The mean IQ level was more in the region with medium fluoride concentration in drinking water (56.68) compared to areas with low fluoride concentration (41.03) and high fluoride concentration (31.59).
So according to that study, having "medium levels" (1.2-2ppm) of fluoride is much better. I checked three random water reports in Florida which had 0.5, 0.7 and 0.9 ppm.
So according to that study, having "medium levels" (1.2-2ppm) of fluoride is much better. I checked three random water reports in Florida which had 0.5, 0.7 and 0.9 ppm.