I was eating my usual tuna at school today and a friend of mine said that tuna was bad not only for the high levels of Hg, but mine had a preservative Pyrophosphate added.

I know that eating tuna is not going to kill me or anything, or they woulden't be able to sell it. But I just wanted to make sure that down the road say when I'm in my 30's I don't have problems you know?

What are your views on this? Should I just stop eating tuna and bring an extra sandwich to make up for it?