One day this summer I sat at home eating alone. In front of me on the table was an unfamiliar box. It contained a special salt for French fries. My children had eaten it in a recreation park and liked it so much that my partner had brought a box home from the local supermarket. Bored as I was, I began reading the label. To my surprise, the most important component of the salt was the taste amplifier monosodium glutamate (MSG). Glutamate and MSG, apparently have a hearty, beef-tea-like taste called “umami.” I am familiar with glutamate in a very different context. The nerve transmitter glutamate plays a role in the amplification of pain. I wondered whether eating glutamate could affect pain in fibromyalgia.
No painkiller is effective enough to beat fibromyalgia. It would be world breaking news when relief of pain could be brought about following discontinuation of dietary glutamate. An authoritative medical journal such as The Lancet would be honored to publish such a finding, and it would be cited worldwide. Many people would benefit from this knowledge.
I am, however, no expert in the area of nutrition. Perhaps it was a stupid idea of me to expect that a simple change in diet would be able to affect pain. I decided to contact a well-known professor of human nutrition. She thought it worthwhile to examine this idea. A talented student would perform the investigation.
Such an investigation had already been done in 2001 by Jerry D. Smith and co-researchers of the Malcolm Randall Veterans Affairs Medical Center, Gainsville, Fla. Glutamate and aspartame had been eliminated from the diet of four patients with fibromyalgia. Patients demonstrated a complete or nearly complete resolution of their symptoms. The investigation did, however, have some shortcomings. Only four patients participated, there was no comparison group that had another diet, and the impact of omitting two substances had been examined simultaneously. As a result, it was unknown which substance induced the beneficial effect. The results were promising, but provided only weak scientific evidence.
We decided to examine this issue thoroughly. During two months, one group of patients with fibromyalgia would obtain a diet with little glutamate. Another group would obtain a diet that could have no impact on pain. In the first group, the pain was expected to lessen as a consequence of the diet. In the second group, no effect was expected. Only after this experiment, the groups would hear to which of the two diets they had been subjected.
In preparation for the research, we investigated scientific literature. Glutamate proved to be present in nearly all dietary proteins such as macaroni, lentils, peas, tomatoes, wheat flower, cheese, meat, fish, fried-rice balls, peanut sauce, peanuts, and toast. It would be virtually impossible to compose a varied and healthy diet without glutamate.
We also wanted to know whether glutamate in food could lead to any change in glutamate in nerve conductance. Unfortunately, scientific literature showed that this is impossible. Almost all glutamate is metabolized in the intestines. Even when a large quantity of glutamate is consumed, hardly any enters the blood. Moreover, from the blood it could still not enter the central nervous system. Thus dietary glutamate is not converted into the glutamate that plays a role in nerve conductance. Therefore, it is highly unlikely that glutamate in food could affect pain.
Perhaps large amounts of glutamate, MSG, or other food additives may adversely affect general health. However, our literature search had taught us that our planned study could not provide evidence for an effect of dietary glutamate on pain. For that reason, we did not conduct the investigation. Regrettably, it was impossible to publish in The Lancet our spectacular recommendation that a simple diet could relieve pain. Instead, our disappointing findings of the literature search have been published in the sound Journal of Rheumatology.
Sometimes I have a nightmare. I dream that a clever professor reads our paper and notices that there is a mechanism by which glutamate in diet might affect pain. Waking up, I squeeze my arm to convince myself that I have been dreaming. To fully forget the creepy nightmare, that very evening, I first eat a lentil soup with vegetables south Indian style. I follow this up with deep fried chicken in a spicy oriental sauce, French fries with a lot of salt on it, and fresh vegetables. For dessert, I have a large piece of tiramisu. Actually, it is quite delicious to be able to demonstrate that dietary glutamate does not affect pain.
Dr. Rinie Geenen, PhD, is assistant professor at the Department of Health Psychology of Utrecht University, Utrecht, The Netherlands. His research involves biopsychosocial aspects of chronic rheumatic conditions. He wrote many scientific and professional publications for patients, scientists, and clinicians.
Smith JD, Terpening CM, Schmidt SO, Gums JG. Relief of fibromyalgia symptoms following discontinuation of dietary excitotoxins. Ann Pharmacother 2001;35:702-706.
Geenen R, Janssens EL, Jacobs JWG, van Staveren WA. Dietary glutamate will not affect pain in fibromyalgia. J Rheumatol 2004;31:785-787.