I'm not sure if certain foods could cause a hormone reaction or not but I'd say an avoid food is capable of causing many problems.
I'm a blood type O+ Non Secretor and on 3/22/08 I decided to devote myself to ER4YT again because of chronic digestive issues. I gave up all dairy at that time, as well as other avoid foods for my type such as wheat bread, flour, oatmeal, corn, oranges, and apples that I was eating daily. It's not hard to do once you get used to it.
Dairy was the main problem food I think I was eating, with wheat not far behind. If you still have health issues I'd look into ER4YT if I were you.
What is a good food for one person may not be for the next person. :)