Dr. Mercola is at it again with a new article: 25 Studies Prove This Reduces Your IQ.
The Fluoride Action Network is also urging communities to pressure their local water departments to place a warning on the water bill, stating that parents should not use fluoridated water to mix baby formula. In November 2006, the American Dental Association has issued this warning to its members—the dentists—but has failed miserably when it comes to actually warning parents...
"… We now have 25 studies that indicate that fluoride is associated with the lowering of IQ. A recent study from Ding et.al… [published] in the Journal of Hazardous Materials… found a lowering of IQ at low levels – not moderate, not high levels, (but) low levels...
They were able to correlate the level of fluoride in the urine, which is a measure of individual exposure to fluoride… there was a very strong linear correlation with lowering of IQ and fluoride concentrations in the urine; very strong.
… What parent in their right mind would put the interest of their children's teeth, even if it worked (to swallow fluoride), above the interest of their brains? It's literally a no-brainer isn't it?
… What Ding et.al showed was that for each one part per million of fluoride in the urine, there was a lowering of IQ by 0.59 IQ points. That doesn't sound much, but when you shift the IQ of the whole population… you will reduce the number of geniuses in your society, and you will increase the number of mentally handicapped. Believe me, in a competitive world, you want all the geniuses that you can get, and you want to minimize the number of children who have to be treated for mental development problems."
The link in the quote leads to another Mercola article which claims to amass 24 studies showing reduced IQ correlated with fluoridated water consumption. He says:
This brings the total to 24 IQ studies that have found exposure to fluoride associated with lowered IQ.
There's a footnote on that quote which leads to this IQ Studies page on the Fluoride Action Network website. There are two links there to "See the 24 published studies reporting an association of reduced IQ with high fluoride exposure." Both of those links go to the same page as the links themselves.
For an example of a study, here is a study by Xiang et al. in which fluoride urinary content was found to correlate with ingested fluoridated water quantities, and then fluoride urinary content was correlated to IQ.
Is there any concern to be had with drinking fluoridated water, especially the claim that it leads to reduced IQ in children? Furthermore, the claim is broadcast by Mercola as more or less universal (not just limited to children); is there credibility to fluoride's effects on IQ at any age?