One effect that has been claimed for fluoridation of drinking water that I didn’t really examine in my previous examination of fluoride toxicity is reduced IQ. The major regulatory reviews have previously concluded there is no evidence for any such link at relevant concentrations, but a new study published ahead of print in Environmental Health Perspectives concluded that “higher fluoride exposure may affect intelligence among children.” Does the study really support an effect on intelligence, and if so what are its implications for water fluoridation?
Originally I was planning on writing something this week on a new study published in Environmental Health Perspectives looking at the possibility of a correlation between living near freeways and autism. However, Science-Based Medicine wrote a thorough evaluation of the study (probably more thorough than I would have had time for), so I encourage you to read theirs instead. In the meantime I’ll try to get something else up before Christmas.
One of the comments on my previous post on fluoride toxicity suggested we are all just guinea pigs in a fluoridation experiment. Is this true? Yes – but we are also guinea pigs for a lot more things. Is it a bad thing? Well, maybe it’s not ideal, but it’s inevitable and it isn’t going to end in the foreseeable future. We are exposed to countless chemicals for which we don’t have complete certainty about the effects, ranging from pharmaceuticals to industrial chemicals to the natural components of the food we eat.
A bit of a storm arose at Scienceblogs the other day when a blogger normally dealing with climate change allowed his father, James Beck, to do a guest post about a new anti-fluoridation book he had co-authored. Needless to say there were strong reactions on either side of the issue, including a response at Respectful Insolence. Since I’d been planning for a while to post something about fluoridation and just hadn’t got around to it, now seems like a good time.
Some of the arguments against fluoridation involve questions about how effective it is – I’m not going to get into that here (though in general the anti-fluoridation sites I’ve looked at use some pretty questionable analyses when downplaying its effectiveness). I’m also not going to get into the ethical side – whether it is right for the government to administer fluoride in drinking water when some of the water users may not want it (though to me it’s not that much different than fortifying milk with vitamin D, enriching flour, etc.). I’m going to focus instead on my own area of expertise, specifically whether fluoride is toxic at the concentrations in drinking water.