Flavor Potentiators do not contribute any taste of their own to the food to which they are added. While it is not known for certain exactly how MSG works or indeed, how the process of experiencing taste functions works current theories hold that taste receptors in the tongue transmit impulses to the brain which is translated as flavor. MSG appears to intensify this taste sensation by temporarily binding itself to these taste receptors in the brain. The simple answer is that MSG is a poison to many people who are sensitive to its effects. During the past decade, a large amount of scientific research has been compiled on the effects of MSG in the body.
Reactions range from mild to very severe.
MSG intolerance is not an allergic reaction but a sensitivity to the chemical. Chemical sensitivities cannot be tested for in the same manner as allergic reactions, which is the reason for pointing out the difference between sensitivity and allergies. People have been diagnosed as having Migraine Headaches, Brain Tumors, Neurosis, Functional Colitis and Depression. After being MSG challenged the symptoms of this diagnosis were reproduced. Severe allergic reactions or anaphylaxis is a generalized reaction this is often severe and fatal.