I guess the point of sharing my experience and my frustration trying to get to the bottom of my problem was to suggest the possibility that it's something you're not tracking.
For example, people who are very very sensitive to Mono-Sodium-Glutamat (Natrium Glutamat) / (free gutatmic acid) sometimes react when auxigro (a fertilizer / pesticide composed of 30% free glutamic acid is sprayed on crops. So, say it's sprayed on potatoes, and you react to potatoes, it sends you down the wrong direction thinking you're allergic to potatoes.
By the way, I forgot to mention an obvious one: nutrasweet / asparatame. I assume, however, that anyone conscious of health enough to be on curezone wouldn't be ingesting that poison, which can most certainly cause brain fog.