From the Mayo Clinic website:
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
Nausea
Weakness
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
From Vanderbuilt University:
MSG Complex
A study was done to test the validity of the symptoms supposedly being caused by MSG. �Self-identified MSG-sensitive subjects� were tested to find the significance of the additive on their symptoms. These subjects were people who believe MSG to be the cause of their symptoms. The test was conducted in a double-blind manner with 5g of MSG or placebo given to the subjects. Subsequent tests were conducted according to the subjects� reactions to only a single test agent; doses of placebo and 1.25, 2.5, and 5g MSG were administered. There were also certain qualifications for the subjects being tested. They had to be:
18-60 years old
had, within 3 hours of a meal alleged to have contained MSG, two or more symptoms such as: sweating sensation, muscle tightness, burning sensation, headache/migraine, chest pain, palpitation/heart pounding, etc.
had to have at least on additional symptom attributed to MSG by the subject
The following estimations were made in regard to the likelihood of responses to MSG:
Estimated rates of reactions to placebo of 5% and 10%
Estimated rates of reactions to MSG of 30% and 40%
Sample sizes of 27-71 were required to show a difference between placebo and MSG at a significance level of 0.05 and power of 80%. A sample size of 60 was used.
The design of the study was as follows:
In an initial challenge, 5g of MSG or placebo were, in random order, ingested by subjects, on different days, on an empty stomach. This act would filter out negative and ambivalent responders. The other subjects to only one challenge doses underwent another challenge where more tests could identify a dose-response curve and decrease the likelihood of placebo responses. MSG was dissolved in 200mL of citrus beverage and the placebo was the same beverage without the additive. A positive reaction was defined as the occurrence of �2 index symptoms (those identified by subjects before the challenge). The subjects were unaware of the definition of response. If fewer than the required number of index symptoms occurred, it was considered a negative response. Subjects were questioned every 15 minutes regarding their symptoms. If no symptoms were present after 2 hours, the subject was released. If the subjects had the symptoms, they were challenged again at a later date. The interval between tests was at least 1 day. Subjects who didn�t respond to either test agent or both of them didn�t participate in further study. Subjects who only responded to one of them were rechallenged. To determine the severity of the symptoms, subjects used a scale of 1-3. (1=mild, noticeable but causing only slight discomfort, 2=moderate, definitely troublesome but not incapacitating, or 3=severe, having significant impact on the subject.)
The following are statistics of the group tested:
n = 634 subjects
122 could not be contacted for an interview
397 were not eligible
5 were excluded because their described symptoms were not considered to be part of the Chinese restaurant syndrome
out of 110 eligible subjects, the first 61 who agreed to be tested were the people who participated in the study
25% of the subjects were male
59 were white, 1 black, 1 oriental
mean age=38 with a standard deviation of 9 years
mean weight=75kg, standard deviation=17kg
mean height=170cm, standard deviation=9cm
58% of subjects had history of atopy (hereditary allergy characterized by symptoms produced upon exposure to the exciting antigen without immunization)
(Yang, Drouin, Herbert, Mao, Karsh-1997)
Overall Conclusions to Study
MSG is such a common additive in so many foods. It is generally know to be a safe additive. There is evidence, however, that some people may be MSG sensitive and they have the potential to have more severe reactions than those not sensitive to MSG. The average daily intake of MSG is 0.3-1g, but some restaurant meals may contain up to 5g. MSG has been blamed for many ills � in this study, it is shown that among the people who identified themselves as MSG-sensitive, many of their symptoms occurred while being tested. These symptoms were specific ones that they previously identified by the subjects.
It�s quite obvious by looking at the charts and graphs, that the rechallenge given to the 36 subjects showed MSG to play a significant role in instigating certain symptoms, despite the fact that they are somewhat skewed to what we may have thought the results to be. My whole intent in investigating this topic was to find the role, if any, that MSG played in the instigation of migraine headaches. In researching, however, I was presented with more information, finding out that MSG is known to cause more than just headaches, as shown in this study. Before looking into studies done on the topic of MSG�s effects on migraines, I deduced that there could possibly be a link between the two, however, this study gives much stronger evidence that MSG is troublesome more to some people than to others.
Bibliography
Diamond, S., Prager, J., & Freitag, F.G. (1986). Diet and headache. Is there a link? Postgrad Med, 279-86
Drouin, M.A., Herbert, M., Karsh, J., Mao, Y., & Yang, W.H. (1997). The monosodium glutamate complex: assessment in a double blind, placebo-controlled, randomized study Journal of Allergy Clinical Immunology, 757-62
I would rather trust these sources and my neurologist that treated me for migraines than studies sponsored by the food industry or panels that the government put together that were made mostly of people from the food industry. After all, it is in the food industrie's best interest to keep selling garbage.
