Super Science: Monosodium Glutamate & Chinese Restaurant Syndrome
Food as Herbs, Health, and Medicine
Fall Volume: 1994 Issue: 1(1) page(s): 10, 11, and 12
George, a physician with whom I had done my internship, called recently and asked if could have dinner together. We enjoy discussing, while eating, recent developments in medicine and in photography, a hobby we share. I suggested meeting at a Chinese restaurant. He was enthusiastic, but insisted that it be the one where he frequently dined.
Once there and seated, George confided that this was the only Chinese restaurant he now chose to patronize because several years ago he had many attacks of Chinese Restaurant Syndrome. He blamed them on the use of monosodium glutamate (MSG). George then explained that this restaurant was the only one where he felt secure that no MSG was used.
The illness dubbed 'Chinese Restaurant Syndrome' was first described in 1968 by Robert Ho Man Kwok in a letter to the prestigious New England Journal of Medicine. He reported that MSG, which was used by Chinese chefs as a flavor enhancer, might be responsible for the syndrome of headaches, flushing and palpitations that some people experienced when they were eating in Chinese restaurants.
While George knew of my interest in Chinese cuisine he was unaware of my interest in Chinese Restaurant Syndrome. He had no idea I was reviewing the literature on reactions to MSG for a lecture to be delivered
at an upcoming symposium.
I went on to explain that while preparing my talk, I had discovered that among researchers, a good deal of skepticism exists about the authenticity of MSG-induced illness because careful research has shown that very few people experience detrimental effects from MSG.
I went on to tell him that studies have shown that when people who believed themselves sensitive to MSG, drank soup with and without MSG; most who claimed to be sensitive to its effects had no reactions after drinking the soup that contained more MSG than typically found in Chinese food.
My own experience with people who believed they were sensitive to MSG taught me that such people are usually very sure of their ability to identify any foods that contain this flavor enhancer. George was no exception.
As I had expected, he suggested we set up a 'double-blind' experiment to see if he could recognize MSG when he ingested it. A 'double-blind' study is one in which neither the experimenter nor the subject knows what ingredients are in each of the foods prepared for consumption.
Two weeks later, on a Monday evening, George came to my home. I explained how
we were going to conduct our 'double-blind' experiment, and he agreed. I had already prepared a batch of chicken soup without using MSG. I had also already divided it in three portions, adding a teaspoon of MSG to only one of them.
Karen, another friend, stopped by. She was shown which bowl of soup had the MSG. Out of sight, she labeled the bowls 'Monday,' 'Tuesday,' and 'Wednesday' and then she left. Only she knew which bowl of soup contained the MSG and George was told that one or more of them contained MSG.
That evening, and each of the next two evenings, George came and drank one bowl
of soup. As he had always reacted to MSG within thirty minutes, we agreed he would remain at my home for an hour after eating each of the bowls of soup. George had the first portion that very Monday, and we talked for the next hour. He was sure that there was no MSG in that soup.
Tuesday he came again and had his soup. After we chatted for an hour, he said that he felt fine. Again, he was certain the soup was free of MSG. As he left, he mentioned that he was prepared to experience some discomfort the next evening because he was certain that there was no MSG in either of the two soups.
As George was sure that Wednesday's soup would contain MSG and that he would have a reaction to it, after having the soup that Wednesday, I asked him how he felt. He said that he might be developing a bit of a headache, but his reaction was much milder than the ones he had previously experienced when exposed to MSG. He said he was "fairly sure" that the third bowl of soup
contained the MSG, but wondered if I had 'pulled a fast one' by not putting MSG in any of them.
Only then, did I phone Karen to inquire which bowl of soup contained the MSG.
She said it was in the soup George had consumed on Tuesday. I told this to George and he laughed saying, "I guess that little headache of mine was iust a placebo." George was very surprised that he had no reaction to the soup he had eaten on Tuesday that really did have MSG. Because of this, I agreed that I could select the restaurant when next we decided to meet for Chinese food.
While there may be a few people who react poorly to MSG, many think they are sensitive to it, when in reality they are not. By continuing to request their food prepared without MSG, there is no way for a person to find out their possible degree of sensitivity. When such people have reactions after eating
some foods, they usually assume that someone in the kitchen ignored their instructions not to use MSG. They seldom consider that they may be reacting to another ingredient used in the preparation of that meal.
In 1969, Dr. Olney of Washington University showed that MSG raises blood pressure in rats or monkeys and that infant animals are more susceptible to it than older animals. From that, he concluded this likely to be true in humans.
However, double-blind research studies since then, as did mine with George, have shown that most people can't tell which food has any MSG and which food does not.
WARNING: If you have severe reactions to MSG such as asthma attacks, do not try to repeat the test mentioned in this article and by no means should you ingest MSG.
FOR THOSE WHO WANT MORE INFORMATION: Dr. Goldberg suggests three articles for starters: Kerr, GR et al. Objectivity of food-symptomatology surveys.J. Amer. Dietet. Assoc. 77: 263-68, 1977;
Rosenblum, I. et al. Single and double blind studies with oral monosodium glutamate in man. ToxicoL AppL Pharmacol. 18: 367-73, 1971; and Young, E. et al. A population study of food intolerance. Lancet 343:1127-30, 1994.