Anybody here had an experience with yeast extract powder? I had some crisps last night and was not very well later in the night. I hadn't eaten anything suspicious for dinner. Looked on the crisp packet - which my husband had bought, and discovered they contained yeast extract powder - the only ingredient I was unfamiliar with. I don't eat marmite - love it but keep away from it in case it does something to me. So I am wondering whether this test extract powder is dodgy.