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　　You've probably noticed that MSG appears regularly among the ingredients of your favorite foods. But what is it? MSG (or monosodium glutamate) is a chemical commonly used to add flavor to salty or sour tasting foods. The average person knows almost nothing about it, but today MSG is found in everything from potato chips to soup.

　　The main component of MSG—glutamate—was identified by Professor Kikunae Ikeda in 1908. But Eastern cooks have been using glutamate-rich seaweed as flavoring for more than 1000 years. Large amounts of glutamate are also found in mushrooms, cheese and tomatoes—which is why they're particularly useful for adding flavor to other foods.

　　MSG itself, however, isn't natural. It's made by fermenting corn, sugar beets or sugarcane to produce a white crystal that can be easily mixed with most foods. It has no nutritional value and no flavor of its own. Instead, it simulates flavor by exciting the brain of the person that is eating it.