Could Monosodium Glutamate Cause Multiple Sclerosis?
Amy Elizabeth Terlisner, NMD
In today’s medical community, the prevailing theory is that multiple sclerosis (MS) is an autoimmune disease. However, as inquisitive NDs, we are always searching for the initial trigger of the autoimmune condition. We see connections between onset of an autoimmune disease and viral infection, increase in life stressors or a GI disturbance. This is, for us, the underlying cause.
What is the Pathology of MS?
Researchers have isolated the location of MS lesions, which stem from degradation of oligodendrocytes. Oligodendrocytes line the axons of the central nervous system, and a single oligodendrocyte can insulate up to 50 axonal cells. Each oligodendrocyte produces a myelin sheath that decreases ion leakage from axonal cells and decreases overall electrical resistance of nerve impulses.
What Antibodies are Found in MS?
Most of us are familiar with the gold standard for diagnosis of MS: the brain MRI, which shows a standard lesion when MS is present. In searching for evidence that MS is truly an autoimmune disease, I wondered if there were autoantibodies that we could measure in the serum. A search on Pubmed described a study by Markus Reindl et al. out of Austria and Germany. These researchers looked at two antibody responses to the myelin antigens myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) in several groups of patients. They divided groups of patients into MS, other inflammatory neurological diseases, other non-inflammatory neurological diseases and rheumatoid arthritis subjects.
These researchers found that 38% of MS patients were seropositive for antibodies to MOG-Ig compared with 28% seropositive for anti-MBP. Other inflammatory neurological disease patients had similar frequencies of serum IgG antibody responses to MOG-Ig (53%) and MBP (47%), whereas serum IgG responses to MOG-Ig were rare in patients with other non-inflammatory neurological diseases (3%) and rheumatoid arthritis (10%). Anti-MBP Ig antibodies, however, were a frequent finding in other inflammatory neurological disease patients (23%) and rheumatoid arthritis patients (60%). The researchers stated that the results “provide clear evidence that anti-MOG-Ig antibodies are common in CNS inflammation.” These researchers found that in other inflammatory neurological diseases these antibody responses were transient, whereas they persisted in MS (Reindl et al., 1999).
The concept of CNS inflammation and the startling finding in the previous study that 60% of rheumatoid arthritis patients have antibodies to myelin basic protein led me to ponder if antibodies were really a side effect of another etiology. Considering another cause of CNS inflammation, I turned to learning more about the oligodendrocyte and investigated its two major receptors: alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) and N-methyl-D-aspartic acid (NMDA). The agonist of both receptors is the amino acid glutamate, the most common (excitatory) neurotransmitter in the brain. Interestingly, in excess concentration in the extracellular fluid, glutamate will hit these receptors, causing an influx of calcium into oligodendrocytes, ultimately resulting in cell death (Leuchtmann et al., 2003; Pitt et al., 2003). In too high a dose, glutamate can be damaging. The term used commonly in the medical literature to describe this phenomenon of cell death by over-activation is “excitotoxicity.” Even though our bodies naturally manufacture glutamate, medical experts believe sources in processed foods, such as monosodium glutamate (MSG), raise the neurotransmitters’ levels to potentially toxic heights in our CNS tissue (Adams, online posting). The lesions produced by glutamate-induced cytotoxicity seen on MRI findings look distinctly like MS lesions (Srinivasan et al., 2005). In fact, medical literature shows that glutamate excitotoxicity is a current theoretical cause of MS (Pitt et al., 2000).
Is it possible that exposure to excessive levels of glutamate in our diet could lead to MS or other neurodegenerative diseases? How do we ingest high levels of glutamate in our diet? The most concentrated form of added glutamate in foods is MSG.
What is MSG?
MSG was initially discovered in the early 1900s and patented by Ajinomoto Corp. of Japan in 1909. From 1909 to the mid-1960s, MSG was prepared by the hydrolysis of wheat gluten, which is roughly 25% glutamate. (Could this be why so many of our patients are allergic to gluten?) Currently, it is produced by fermentation of starch, sugar beets, sugar cane or molasses. As a food additive, it is a flavor enhancer (Truth in Labeling, online posting).
MSG and high levels of glutamate can be found in any product that lists these terms as ingredients: hydrolyzed vegetable proteins, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts, protein isolate, spices, natural flavorings, soy protein isolate, whey, whey protein isolate, dry milk solids, milk powder, broth, maltodextrin, malt extract, sodium caseinate, autolyzed yeast, modified food starch and soy protein concentrate (Battling the “MSG Myth,” online posting).
Another scary source of excess glutamate in our diets comes from a specific crop spray, which is approximately 30% MSG. The spray is used as a growth enhancer of vegetables (MSG Updates, online posting).
Is MSG Linked to Other Diseases?
Too large in scope to discuss in this article, a quick tour on the website www.msgtruth.org discusses research linking MSG to many diseases, including: ADD, ALS, asthma, atrial fibrillation, autism, diabetes, migraines and epilepsy.
Isn’t Low Vitamin D Part of the Cause of MS?
Thinking back to my medical school training (especially because I was living in overcast Seattle), the link between low vitamin D levels and MS was emphasized. I wondered, however, if vitamin D didn’t play a role in the way neurons processed glutamate. Another search on Pubmed produced one preliminary study that this important vitamin did seem to help neurons lower cellular glutamate toxicity (Taniura et al., 2006). Perhaps additional research will show this connection with more clarity.
Personally, I have not been meticulous in eliminating foods that contain the many ingredients listed earlier. In fact, a quick search of items on my shelf at home reveals lots of hidden MSG – even from products purchased at natural foods stores. I’m excited to see what kind of clinical results I get from making patients aware of these issues and having them eliminate excess glutamate from their diets.
Amy Elizabeth Terlisner, NMD attended Bastyr University. She has an extensive teaching background, which she believes is a critical element of naturopathic medicine. Dr. Terlisner’s specialties include women’s health, cardiovascular disease, gastroenterology, preventive and anti-aging medicine, and bio-identical hormone replacement therapy.
References
Reindl M et al: Antibodies against the myelin oligodendrocyte glycoprotein and the myelin basic protein in multiple sclerosis and other neurological diseases: a comparative study, Brain 122(11):2047-2056, November 1999.
Leuchtmann EA et al: AMPA receptors are the major mediators of excitotoxin death in mature oligodendrocytes, Neurobiology of Disease, 14:336-348, 2003.
Pitt D et al: Glutamate uptake by oligodendrocytes: implications for excitotoxicity in multiple sclerosis, Neurology, 61:1113-1120, 2003.
Srinivasan et al: Evidence of elevated glutamate in multiple sclerosis using magnetic resonance spectroscopy at 3 T, Brain 128(5):1016-1025, 2005.
Pitt et al: Glutamate excitotoxicity in a model of multiple sclerosis, Nature Medicine 6:67-70, 2000.
Truth in Labeling: History of use of MSG. Available: www.truthinlabeling.org/IVhistoryOfUse.html
Battling the “MSG Myth”: Hidden names for MSG. Available: www.msgmyth.com/hidename.htm
Weston A. Price Foundation: MSG Updates. Available: www.westonaprice.org/msg/index.html
Taniura H et al: Chronic vitamin D3 treatment protects against neurotoxicity by glutamate in association with upregulation of vitamin D receptor mRNA expression in cultured rat cortical neurons, J Neurosci Res May 15;83(7):1179-89, 2006.
