From scouring the net I'm finding sites that mention Iodine as a fluoride and heavy metal chelating agent although it is considered dangerous in the hands of the unexperienced practitioner because the body has to pass it through the kidneys.

If this is the case then I would recomend finding a top quality salt which should contain Iodine and supplementing the diet with iodine rich foods. At the very least this should create a natural chelation for fluoride etc.