I had a series of migraines w/ aura last week where I had been relatively miraine free for a while, except the usual around the period ones. I couldn't figure what triggered them out of the blue. I was looking at a web site that stated brewers yeast as a possible trigger. The light went on. I'm a vegetarian and tried a new recipe last week that called for a high concentration of powdered brewers' yeast for the sauce, about 1/2 cup. I ate it Sun. night and all week for lunch at work. I've never had it before (maybe in food in which I didn't know it was contained in smaller concentration). I'm almost convinced that's what caused them. Anyone else have problems with brewer's yeast?