Fluoride’s damaging effects on the brain has been documented by both human and animal studies. Eighteen human studies from China, India, Iran and Mexico and more than 40 animal studies show evidence that fluoride toxicity negatively affects the brain. A Chinese study [Wang SX, ZH Wang, XT Cheng, J Li, ZP Sang, XD Zhang, LL Han, SY Qiao, ZM Wu and ZQ Wang. 2007. “Arsenic and fluoride exposure in drinking water: children's IQ and growth in Shanyin County, Shanxi province, China.” Environmental Health Perspectives 115(4):643-7.] examined 524 children, ages 8 to 12, for “fluoride exposures in relation to intellectual functioning and growth.” The children who were exposed to high concentrations of fluoride through well water -- as high as 8.3 (mg/L)—were compared to a control group of children from neighboring villages whose well water contained 0.5 mg/L of fluoride. The high fluoride group had a four-point IQ score reduction compared with the control group, and the high fluoride group’s urine fluoride level was five times higher than the control group.