MSG (monosodium glutamate)

Flavor enhancer: Soup, salad dressing, chips, frozen entrees, restaurant foods.
MSG is the sodium salt of an amino acid that brings out the flavor in many foods. While that may sound like a treat for taste buds, the use of MSG allows companies to reduce the amount of real ingredients in their foods, such as chicken in chicken soup. In the 1960s, it was discovered that large amounts of MSG fed to infant mice destroyed nerve cells in the brain. After that research was publicized, public pressure forced baby-food companies to stop adding MSG to their products (it was used to make the foods taste better to parents).

Careful studies have shown that some people are sensitive to large amounts of MSG. Reactions include headache, nausea, weakness, and burning sensation in the back of neck and forearms. Some people complain of wheezing, changes in heart rate, and difficulty breathing. Some people claim to be sensitive to very small amounts of MSG, but no good studies have been done to determine just how little MSG can cause a reaction in the most-sensitive people. To protect the public's health, manufacturers and restaurateurs should use less or no MSG and the amounts of MSG should be listed on labels of foods that contain significant amounts. People who believe they are sensitive to MSG should be aware that other ingredients, such as natural flavoring, Torula yeast, and hydrolyzed vegetable protein, also contain glutamate. Also, foods such as Parmesan cheese and tomatoes contain glutamate that occurs naturally, but no reactions have been reported to those foods.