I have heard of things like that before, when I was studying guided imagery and n.l.p (for the record, I don’t work at it, I learned that as a personal enrichment). the lecturer (jew) told us that a few years before, he have noticed that his wife coughed every time he, she or anyone else blessed on the bread (a jewish blessing before one eats bread – this means it happened on a daily basis), and whenever she ate bread (something that didn’t happened in their previous years of marriage). after he talked about that with her they did some thinking and tried to understand when exactly it started, and after that, what could have been the source of that. turned out that one Saturday he gave her a piece of bread that was seasoned with too much salt (jewish ceremony that takes place in every Shabbat feast, apart from the “too much” ofcourse xSD) – causing her cough. after they got that, they worked on “braking the connection” her brain made between salt and bread. I guess you can try figuring out when that started, and go from there in accordance. good luck!