I cut out gluten about 5 months ago, and while I do think it has improved my guts, I don't think it's done a blessed thing for my "Swiss cheese brain". In fact, between medication changes, dietary changes, and going on disability, my Crohn's more or less went into remission. Which allowed my symptoms of Fibromyalgia to stand out more clearly. People with true gluten intollerance may have improved mental clarity when they go off gluten, but I don't believe that is true for everyone who tries it.
As far as suppliments go, I always inform my doctors of every suppliment I take, and I stick to vitamins and probiotics. I haven't done any herbal stuff. Before I tried mixing herbal suppliments in with everything else I take, I'd want to educate myself on possible interactions. And from multiple sources, not just one. (I do this with prescription drugs, too. The only difference is, I buy them all from the same pharmacy, so I use that as one level of my "screening process". I no longer trust my multiple doctors to know what's best for me or which drugs might interact. I wouldn't trust a book or naturopath, either.)