NAG is a useful thing to take, but the body is able to convert L-glutamine into NAG.
I wasn't aware of a specific link between zinc and leaky-gut, but I presume anyone following a varied/ healthy Diet and/or taking vitamin/mineral supps will be getting their daily dose.
I deliberately kept the protocol simple. The key thing is to be getting enough L-glutamine every day.
There's no point bombarding people with lists of things to take, because then they won't take the correct dosages and will end up frustrated. Better to take things one at a time, and take them at the correct dosage, and see what difference it makes.