I checked this claim on Google Scholar. To my surprise, there actually appears to be some credible research linking fluoride in water to lower IQ in children. H

I checked this claim on Google Scholar. To my surprise, there actually appears to be some credible research linking fluoride in water to lower IQ in children. However, studies are typically in China where fluoride levels can be much higher than what is recommended in (e.g. in the US). We are also talking about roughly 0.5-1 IQ points as an average effect size, so not huge. Lastly, note that these are descriptive associations, and possible confounders include the presence of arsenic in drinking water (guess Chinese public health still has some way to go...). Here's what seems like a reasonable meta analysis: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930/ There is a (rather old) NRC report here, which seems like a reputable source: https://books.google.co.uk/books?hl=en&lr=&id=NAB43R0rTV4C https://books.google.co.uk/books?hl=en&lr=&id=NAB43R0rTV4C For a more recent sceptical take, see: http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2013.301857 http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2013.3... with an ungated link at: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.699.9659&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.699... Anyone in the field want to comment on the credibility of this research?