Well, Larry Dossey doesn't look like an obvious pundit in the area (given the work he dedicated to consciousness based healthcare, and specifically to so called "non-local mind", according to Wikipedia), but given the weight of a hydrogen atom (circa 1.67 x 10^-27 kg), at least the decimal order of amount of atoms in an average human body that he gives looks plausible enough; indeed, Dossey might have had a good primary source for the claim about the usual speed of atom replacement in a human body, too.
As to the permanency of permanent tattoos, to me it's true mystery - if only for the short life cycle of skin cells. It looks as though the permanent dye somehow replicates itself...
Anyway, thank you very much for your interesting reply.
Nothing that would make electricity cheaper or sovereign debts lower. I would only like to have a clearer idea about the nature of humans as well as other animals or living organisms in general. Particularly, if something like human organisms exchange their atomic or sub-atomic particles with the environment so quickly as claimed in Realitycheck's quote of Larry Dossey, to me it makes sense to seriously ponder over what - if anything - constitutes the identity of those organisms in the course of time.