Mrs. Weer’d sends me this story:
Harvard University researchers conducted a review of fluoride/brain studies and concluded that there is a possibility of adverse effects of fluoride exposure on children’s neurodevelopment. Children in high fluoride areas had significantly lower IQs than those who lived in low fluoride areas, and the EPA says that there is substantial evidence of developmental neurotoxicity.
Fluoride, or fluosilicic acid, is added to US water supplies at approximately 1 part per million in attempts to reduce tooth decay.
The studies only reviewed water as the primary fluoride source based on high water fluoride levels, though they point out research by Ding (2011) that suggests low water fluoride levels has significant negative associations with children’s intelligence.
Its a bit out of my realm of expertise, and again I can’t see the study methods done. I probably would have skipped this story, if it wasn’t for an excuse to play this clip: