I'm curious what has lead you towards the idea that you have parasites? How would you get them in your brain? I don't really know much about that, but for some reason it seems unlikely to me....
Anyhow, green peppers are known to be difficult to digest and give a lot of gas. Try some cooked squash, spinach, carrots. These veggies all feel pretty benign to me. Otherwise, everything that you mentioned food wise would have made me sick. I seem to feel the best on the above veggies. Cashiews are definitely an issue. I don't suggest that you eat nuts right now, but if you are going to, make sure to soak them first.
That was a lot of HCL to take. Did your stomach feel burning at all?