Lodi,
I've done thorough testing of gluten relief, and don't believe the L-Threonine had any interference.
As far as the slippery elm powder, did you get the organic kind?
Here's how you take it:
After each meal, put 1 tablespoon of it + probiotics (VSL #3) into 2 oz. of room temp filtered water, you can add a little honey to it if you like, mix it up, it will start to gel, and drink it down. If it gets too thick, you can add more water to liquify it.
While I was flaring, I took this after each meal.
Now in remission, I still take it but only after dinner.