Monosodium glutamate (MSG): What is it and is it harmful?

Monosodium glutamate (MSG) is a flavor enhancer commonly added to Chinese food, canned vegetables, soups and processed meats. Although the Food and Drug Administration (FDA) has classified MSG as a food ingredient that is "generally recognized as safe," the use of MSG remains controversial.

MSG has been used as a food additive for decades. Over the years, the FDA has received many anecdotal reports of adverse reactions to foods containing MSG. But subsequent research found no definitive evidence of a link between MSG and the symptoms that some people described after eating food containing MSG. As a result, MSG is still added to some foods.

A comprehensive review of all available scientific data on glutamate safety sponsored by the FDA in 1995 reaffirmed the safety of MSG when consumed at levels typically used in cooking and food manufacturing. The report found no evidence to suggest that MSG contributes to any long-term health problems, such as Alzheimer's disease. But it did acknowledge that some people may have short-term reactions to MSG. These reactions — known as MSG symptom complex — may include:

• Headache, sometimes called MSG headache
• Flushing
• Sweating
• Sense of facial pressure or tightness
• Numbness, tingling or burning in or around the mouth
• Rapid, fluttering heartbeats (heart palpitations)
• Chest pain
• Shortness of breath

Symptoms are usually mild and don't require treatment. However, some people report more severe reactions. The only way to prevent a reaction is to avoid foods containing MSG. When MSG is added to food, the FDA requires that "monosodium glutamate" be listed on the label — or on the menu, in restaurants.