I’m surprised you’re getting such a reaction from the wholefood. Japanese people eat this stuff all the time, and doctors certainly haven’t advised against it in the past few thousand years. How much are you eating?
You can get nattokinase as a supplement if you can’t handle natto or want to avoid the thyroid-busting, testosterone-lowering soy nasties. Maybe this is where the anti-clotting issues come into play though, and natto does have the advantage of vitamin K2, mucilage and probiotics.
Biofilm busting is supposed to be a short-term process, so I guess a few nasties could be justified. I’ve been interested in it since I read Ayers’ blog, but I’m not sure when to do it.