I just read somewhere that it's not a good idea to eat too much lustre dust so it should be used sparingly. Anyone else ever read this? Why would that be?
Most but not all dusts are actually labeled non-toxic. Which means that it shouldn't hurt you (think glue) if you eat it, but it isn't actually meant to be consumed.
There are a few people that do make FDA (edible) dusts. Wilton's pearl dust are FDA approved, so are Crystal Colors. I think there is another brand but I'm not sure.
There are also a few dust out there that are labeled non-edible. Non-edible isn't the same as non-toxic. It means that they should not be consumed at all.