The truth is that many people in the late 80's and the early part of the 90's claimed allergic reactions to food prepared with Monosodium Glutamate (MSG). Reactions included nausea, headaches, and general feelings of discomfort. Although there is proof that a small segment of the population does suffer from an adverse reaction to MSG, it is also a little known fact that mushrooms are filled with natural MSG, and most people do not have any problems with them. MSG is a salt alternative that is used commercially as well as in a lot of Chinese cooking. It's a lure that you can use to accent other flavors, without making them seem too salty.