There's all sorts of stuff zinc is supposed to help with but I don't know that there's good research on much of it.

My dental hygenist says my tongue is very smooth--looks kind of like scar tissue, not the nornal bumps people have on their tongue. But I think I pretty miuch have most of my sense of taste back (I am over three years out from radiation) so somehow, even if my tongue looks different, there are still working taste buds there somewhere. Go figure!