Monosodium glutamate (MSG) is found in Asian style foods like noodles and other dishes.
Monosodium glutamate has no nutritional value, but does not harm the body. It is safely certified by the Joint Commission on Food Additives (JECFA), the World Health Organization (WHO), and the Food and Agriculture Organization (FAO).
MSG is widely used throughout Asia. In Japan the umami flavor is tied to glutamic acid and MSG is the sodium salt. Reports of fake MSG have surfaced occasionally in poorer Asian countries.
While most can consume up to 6 grams a day without problems, some have a histamine reaction that can be unpleasant. It is not altogether clear why this reaction occurs.
MSG is seen in noodles and in many soybean based products which are staples in Asian nations.
One of the best solutions to MSG problems is to have a glass of lemon juice with a little table salt added. This should be followed with at least 3-4 cups more water to help the body rid itself of the MSG. A person should try to stay in a cool place to minimize perpetration so that the kidneys can rid the body of MSG faster.
For the most part, respectable indoor Asian restaurants only use a small amount of MSG which should not be problematic. Street vendors may have much higher levels of MSG which can be more problematic fo those who are sensitive.