It is quite possible that the headache you get, the nausea you feel, the fatigue you can't get rid of are all side effects from one single thing - the MSG. Everybody has heard of it but do we really know about it? In order to understand, we first have to know what glutamic acid is.
Glutamic acid and its ions and salts, called glutamates, are flavor-enhancing compounds, which provide a savory taste to food (one of the five tastes). Glutamic acid naturally occurs in many fermented or aged foods, including soy sauce, fermented bean paste, and cheese, and is also a component of hydrolyzed protein such as yeast extract. Glutamate is a key molecule in metabolism as well as a principal excitatory neurotransmitter in brain.
The sodium salt of glutamic acid, monosodium glutamate (MSG), is a widely used additive in the food industry. It is practically an artificially manufactured glutamic acid that normally occurs naturally. As mentioned earlier, glutamic acid is responsible for one of the five tastes. Normally, natural glutamic acid is detected by your taste buds as a signal to the presence of protein in food (just like other receptors let you detect carbohydrate or sweet flavor). MSG, on the other hand, tricks your tongue into thinking that the food you are consuming is high in protein and nutritious; it changes your perception of not only the taste but also the nutritious quality of the food consumed.
You may ask why would anyone add MSG to the food? The answer is simple. The illusion created by adding MSG to a food product enables the food processor to add less real food. Similarly, the illusion of more protein in a food allows the food producer to put less protein in it. When you eat this food, you feel as if you are getting what you need because your body even tells you so; however, your taste buds are being tricked by the MSG.
MSG also acts as the same neurotransmitter that your brain and other organs, including pancreas, use to initiate certain processes. Have you ever eaten a large quantity of something and inexplicably felt hungry an hour later? MSG stimulates your pancreas to produce insulin, even if there are little to no carbohydrates in the food you are eating. Insulin gets released, your blood sugar drops, and the result is craving for more food. You end up eating a lot only to feel hungry very quickly again. Sounds like a recipe for weight gain, doesn’t it?
However, weight gain is only one of the possible effects of eating high amounts of foods with high amounts of MSG. It has been reported that some other symptoms may include: numbness, burning sensation, tingling, facial pressure or tightness, chest pain, headache, nausea, rapid heartbeat, drowsiness, weakness, difficulty breathing and in some cases MSG can exacerbate asthma and cause hives. Remember what MSG is? It is an artificially manufactured glutamic acid and its salts - glutamates. Excess glutamate is actually toxic to the neurons in the brain, for example - Lou Gehrig's disease, in which motor neurons gradually degenerate and die, results from excessive glutamate production. Most researchers feel that in Lou Gehrig's disease, glutamate continues to accumulate and stimulate the nerve until the nerve becomes exhausted and dies. Do you still feel like voluntarily ingesting excess glutamate?
FDA does require manufacturers to disclose the use of MSG. The most common places to find high amounts of MSG are canned soups, instant noodles, almost all fast foods, many chips and other snack foods, frozen dinners, salad dressings, grill spices, and most chicken and beef stock. For more information, I recommend a book by George R. Schwartz The MSG Syndrome.