My 10 year old daughter recently had severe migraines. MSG can cause migraines, among other bad things.
The following ingredients ALWAYS contain MSG:
Yeast extract, Maltodextrin
Hydrolyzed oat flour
These two OFTEN contain MSG:
If MSG is contained in an ingredient that is listed on a food label, it doesn't have to be labeled by itself.
My daughter is vegetarian like me and she likes eating products like Chik Patties and Sausage Patties from Morningstar Farms. I contacted Morningstar Farms to ask about MSG in their products... such as the Chik Patties and Sausage Patties... here is their response. Notice how they say "small amounts". That is interesting because you always need only a small amount of MSG, a sprinkle, and that is still enough to be unhealthy. My 10 year old daughter recently suffered a horrible migraine, and there is some evidence that linked it to MSG.
UPDATE APRIL 4, 2013:
I wrote the blog post in 2010 and I checked Lightlife's website now and it shows that the TEMPEH is organic, but not the other items are not, and the other items include MSG, in the form of "Yeast Extract". To be safe, I stick with their ORGANIC TEMPEH (no msg)!
I added this as an updated edit... it's too bad some companies devolve... Morningstar Farms now uses GMO Soy! (Genetically Modified Soy)
My best advice is to avoid most processed soy products unless they are labeled organic, gmo-free and you have checked the label for the MSG sneaky names!
Morningstar Farms® Consumer Affairs 020901656A ...
Thank-you for contacting us concerning the monosodium glutamate (MSG) used in some of our products. Our nutritionists and food scientists work very hard to develop products that are acceptable for our consumers. Small amounts of MSG are used in the product to achieve the desired taste and texture. We would never use an ingredient that is unsafe for our consumers. The Food and Drug Administration, the National Academy of Science, and the American Medical Association all have affirmed the safety of MSG. Even so we understand there is a limited population who have shown a sensitivity to it. Glutamate occurs naturally in protein-containing foods such as cheese, milk, mushrooms, meat, fish, and many vegetables. Glutamate is also produced by the human body and is vital for metabolism and brain function. We are sorry to learn that this ingredient has caused concern for you. We will share your comments with our food development teams. We do have many other products that do not contain MSG that you might enjoy. Thanks, again, for your inquiry. We hope you will find this information helpful.
Best of health,
Mark A. Suriano Consumer Specialist Consumer Affairs