What Are the Dangers of Monosodium Glutamate (MSG)?

                                                                            What is MSG?
(if it becomes too sciency just scroll to the bottom and view the “take aways”)


MSG is an acronym for monosodium glutamate, which is  a salt amino acid compound composed of glutamic acid (aka glutamate) and sodium similar to how table salt is a compound of sodium and chloride. This means you’re not just getting salt, which we know in large quantities can have adverse health effects. It is however, also important to understand that MSG can be either used as an additive (processed MSG) or it can be found naturally occurring in such foods as tomatoes, mushrooms, peas, potatoes, grapes, various fruit juices, and various cheeses. When it is found as an additive it is generally created through the fermentation of such carbohydrates as sugar beets, sugar cane, molasses, and starch, and added to foods such as soups, and many Asian dishes.

So the logical question is why is it important that the MSG is a sodium amino acid compound? Well it’s important because of what the amino acid itself does, and what its role is in the body. The amino acid portion which we can refer to as either glutamic acid or simply glutamate is an excitatory neurotransmitter, which means it is a brain chemical that serves to stimulate the brain (whereas an inhibitory neurotransmitter, is a brain chemical that serves to calm the brain). As such it is thought to serve in cognitive function, learning, and memory making it is an important amino acid. However, it is a non-essential amino acid. A non-essential amino acid simply means that our body is able to produce the amino acid, whereas essential amino acids only come from food sources. In addition, to this fact, we also get glutamate naturally from many common foods such as tomatoes, potatoes, and cheese for example, so our bodies are not likely deficient in this amino acid.  So why use MSG if we are likely getting more than enough already?

Take aways:

1. The amino acid in MSG acts as a brain chemical for important functions in the brain such as learning, and memory
2. It is naturally found in foods such as tomatoes, potatoes, cheeses, grapes, and various fruit juices
3. It also can be man-made and added to food (commonly added to asian foods)

                                                                           Why use MSG?

MSG is added for flavor. Specifically it is added to give your body the sense that the food it is consuming is heartier than it actually is. This specific taste is called umami. It is the the flavor of “meaty” and is one of the five basic flavors. The others are salty, sour, sweet, and bitterness.

                                                                  So what’s the hype about?

The hype to some extent likely comes from the movement of “all natural” foods, and herbs. I am an advocate of whole foods, however, it is not uncommon for people to associate natural with safe, which is not always the case. Nearly any substance in too high a quantity becomes toxic. For example the top 10 most important nutrients, which are: water, calcium, magnesium, sodium, chloride, potassium, selenium, iron, zinc, and chromium are all toxic if over consumed. In fact the trace minerals which are selenium, iron, zinc, and chromium are only good for us in very small quantities (and thus the term trace).  That being said, when we process a food, we very frequently make it more potent, or we make it more widespread (i.e. adding it to more foods) than when it is in its whole food form which is true in the case of MSG.

Shortly after the debut of man-made MSG the FDA identified MSG as “GRAS” (Generally Recognized as Safe). Since this time the FDA has received numerous reports claiming MSG reactions, however, there has not been enough evidence to substantiate the claims. Some of the harmful symptoms thought to be attributed to the over consumption of MSG are:

                                                                             -headaches-
                                                                       -triggering of ADHD-
                                                                        -heart palpitations-
                                                                                -flushing-
                                                                               -sweating-
                                                                           -fascial tightness-
                                                               -numbness, burning in the face-
                                                                                 -obesity-
                                                                         And the list goes on…..

                                                                 Are these claims legitimate?

In short, the answer is, we don’t know. The FDA believes them to be unfounded. For every study that suggests MSG is linked to these symptoms, there’s another study that shows the opposite. When it comes to studies conducted on rats however, there’s pretty conclusive evidence that MSG contributes to ailments, however, we are not rats, but should still exercise caution. You can proceed with caution by:

1.  Noting, or identifying if you have an allergy or sensitivity to MSG (and there are people that do)
2. Or self identify if you’re getting MSG in large quantities, or are eating an abundance of processed foods, especially Asian processed foods, soups, and restaurant cuisine.

3. ​Make necessary changes to limit consumption of these processed foods, or see a physician that may be able to help you manage the allergy
4. Remember MSG is not inherently dangerous, in fact our bodies need glutamate, but like any substance, if consumed in too large a quantity it becomes toxic

                                                           What do studies say about MSG?

In your ventures online you may have seen these claims about how bad MSG is for you. You may have even read sites, that say things such as “studies prove”, “it has been proven”, “the science is in” among many other statements claiming that we have “proof” on MSG causing all these ill effects.


So before we discuss what the scientific studies say, remember a singular study does not prove anything. A study suggests there MAY be a relationship, and either SUPPORTS or COUNTERS previous findings. Additionally, the studies are performed with doses of MSG well above normal consumption levels found in naturally occurring foods.

So here’s a brief run down and the caveats of the studies listed below:

-In a 2011, and 2008 study an association was found between high MSG intake and obesity. However, there was also an association of increased caloric intake, and reduced vegetable consumption, making it as likely that weight gain came from many poor food choices instead of simply consumption of MSG. (Ka et al., 2011 ) (He et al., 2008)

-In a 2015 study,an association was determined between increased MSG intake and kidney problems. The caveat, the study was done on rats.(Sharma, 2015)

-Another study indicated there appears to be a relationship between high intake of MSG and headaches. The caveat, is that 88% of the time the participant was able to identify if they were taking the MSG or a placebo, which puts the study at risk for bias. (Shimada et al., 2013)

-In 2012 there were two studies that strove to identify the impact of MSG on asthma. No correlation was found. (Zhou, Y., Yang, M., & Dong, B., 2012) (Shi et al., 2012)

-While not specific to MSG or adverse impacts a 2006 study analyzed drugs used to mediate the glutamate in the brain for people suffering from OCD (obsessive compulsive disorder), which appears to show promising results. This supports the concept that glutamate when unbalanced in the brain can cause certain neurological problems. (Pittenger, C., Krystal, J. H., & Coric, V., 2006)

                                                                                Conclusion

Like any other substance you should be aware of your intake, and it seems likely that a chronic high intake of MSG may contribute to the typical issues found with any other high salt diet. Most substances when consumed in high quantities are toxic, and as is the case with MSG some people do have a sensitivity or an allergy to it.  Additionally, the role it plays as a brain chemical leaves room for reasonable speculation as the neurological impacts it could have if unbalanced, and should warrant caution. This caution should be doubly so in the case of children.

In closing, it seems fair to saying MSG consumed OCCASIONALLY whether dining out for Chinese food or the occasional canned soup should not pose any major concern. However, every day consumption of largely processed foods is not advised and should still warrant a watchful eye.  

References:

Ka, H., Du, S., Xun, P., Sharma, S., Wang, H., Zhai, F. & Popkin, B. (2011). Consumption of monosodium glutamate in relation to incidence of overweight in Chinese adults: Chinese Health and Nutrition Survey (CHNS). The American Journal of Clinical Nutrition, 93 (6): 1328-1336. doi:10.3945/ajcn.110.008870


He, K., Zhao, L., Daviglus, M. L., Dyer, A. R., Van Horn, L., Garside, D., … for the INTERMAP Cooperative Research Group. (2008). Association of monosodium glutamate intake with overweight in Chinese adults: the INTERMAP Study. Obesity (Silver Spring, Md.), 16(8), 1875–1880. http://doi.org/10.1038/oby.2008.274


Sharma, A. (2015). Monosodium glutamate-induced oxidative kidney damage and possible mechanisms: a mini-review. Journal of Biomedical Science, 22 (93). doi:10.1186/s12929-015-0192-5


Sharma, A., Prasongwattana, V., Cha’on, U., Selmi, C., Hipkaeo, W., Boonate, P.,...Reungiui, S. (2013). Monosodium glutamate (MSG) consumption is associated with urolithiasis and urinary tract obstruction in rats. PLos ONE 8 (9): e75546:https://doi.org/10.1371/journal.pone.0075546


Bawaskar, H. S., Bawaskar, P. H., & Bawaskar, P. H. (2017). Chinese restaurant syndrome. Indian Journal of Critical Care Medicine : Peer-Reviewed, Official Publication of Indian Society of Critical Care Medicine, 21(1), 49–50. http://doi.org/10.4103/0972-5229.198327


Shimada, A., Cairns, B. E., Vad, N., Ulriksen, K., Pedersen, A. M. L., Svensson, P., & Baad-Hansen, L. (2013). Headache and mechanical sensitization of human pericranial muscles after repeated intake of monosodium glutamate (MSG). The Journal of Headache and Pain, 14(1), 2. http://doi.org/10.1186/1129-2377-14-2


Shi, Z., Yuan, B., Wittert, G. A., Pan, X., Dai, Y., Adams, R., & Taylor, A. W. (2012). Monosodium Glutamate Intake, Dietary Patterns and Asthma in Chinese Adults. PLoS ONE, 7(12), e51567. http://doi.org/10.1371/journal.pone.0051567


Zhou, Y., Yang, M., & Dong, B. (2012). Monosodium glutamate avoidance for chronic asthma in adults and children. Cochrane Database Syst Rev, 13 (6), CD004357 doi: 10.1002/14651858.CD004357


Pittenger, C., Krystal, J. H., & Coric, V. (2006). Glutamate-modulating drugs as novel pharmacotherapeutic agents in the treatment of obsessive-compulsive disorder. NeuroRx, 3(1), 69–81. http://doi.org/10.1016/j.nurx.2005.12.006

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