Monosodium Glutamate: Bad for your brain, your figure, and your health

February 21, 2007 in Food Science, ingredient

Monosodium Glutamate

*See note at bottom of this page.

My objective in writing this article is to present the facts about Monosodium Glutamate (MSG) and let you decide if its as benign as the recent foodie hype over at the New York Times (China’s True Dash of Flavor by Fuchsia Dunlop) would have you believe.


MSG was discovered (1908) by Kikunae Ikeda (Tokyo Imperial University) when he was trying to pin down the chemistry behind the flavor later termed “umami“, a Japanese word that is the “IT” word amongst name-dropping with-it foodies today. He isolated this flavor from seaweed broth and called it Monosodium Glutamate. With the help of the Ajinomoto Corp of Japan, Ikeda patented MSG in 1909 and it was made commercially available for the first time. Thus, MSG has been around and in commercial use for almost 100 years. MSG was desirable because it boosted the sensation of “savory” flavors in food, especially important if you are involved with vegetarian cuisines or if you are preparing low-protein content foods for mass marketing.

MSG is now so ubiquitous in our food chain (east and west) that you would be very hard pressed to go MSG-free. As you would expect, junk foods and instant foods like soups and other mixes contain MSG. Prepared food in your grocery stores and at fast food outlets (KFC chicken skin is massively loaded with MSG) and fine dining restaurants alike are awash in MSG. Red meats, poultry, and other off-site prepared meat products are either sprayed with MSG containing solutions (Sanova, a pesticide) or injected with MSG containing compounds (hams, turkey, chicken, etc).

Prepackaged hamburger patties have MSG. Fruits and vegetables are sprayed with MSG containing washes (Auxigro, a metabolic crop primer, almost 30% free MSG). Baby foods had sub-lethal levels of MSG in the 50s until congressional hearings were held. Since then, the word Monosodium Glutamate was been removed from the labels of baby food jars but not from the food within. If you read the labels, you will recognize some of the euphemisms such as tapioca starch, modified food starch, flavorings, etc. (e.g., an ingredient list for Beechnut “Apple Delight”: apples, water necessary for preparation, dried egg yolks, citric acid, ascorbic acid (vitamin c) and zinc sulfate.) When you see the word “citric acid” in prepared food ingredient lists, think MSG. Industrial citric acid is not made from citrus fruits, its made from corn. Its not pure either. Once the citric acid is made from corn, it is contaminated by corn proteins which the producers (e.g., Archer Daniels Midland Company – ADM) do not waste time or money on removing. Those proteins are degraded or hydrolyzed into free MSG. (See this link for this information and more).


  • Autolyzed yeast
  • Calcium caseinate
  • Gelatin
  • Glutamate
  • Glutamic acid
  • Hydrolyzed protein
  • Monopotassium glutamate
  • Sodium caseinate
  • Textured protein
  • Yeast extract
  • Yeast food
  • Yeast Nutrient

You probably recognize some of these terms if you read labels at all. You might wonder, “Where are they getting all this hydrolyzed protein,” and you will feel nauseated when you find out. Hydrolyzed protein is often made from un-salable vegetables. These ugly (rotten?) veggies are boiled, not in water, but in vats of acid. The plant tissues are broken up and acidified and eaten away by caustic chemicals. It doesn’t end there. After this bath in acid, the veggie-acid slurry is then neutralized with a caustic soda. When this is added, the proteins coagulate into a brown sludge that then burbbles up to and solidifies as a sludge mat on the surface of the vat. This brown sludge (the end product!) is dried and powdered and is sold as hydrolyzed protein and is next seen on your tongue after eating that Dorito or those ramen noodles. (See this link for more on this) Natural, from nature, by the same standards that cyanide would be natural.


So whats the big deal, what is this chemical and what is it doing after all? MSG is a glutamic acid. Glutamates are neurotransmitters that effect the signaling of nerve impulses in certain neurons. With respect to flavor, taste is facilitated by the selective excitation of your tastebuds (neurons) (see these two links for some of the anatomy and physiology abound taste and smell). Glutamates such as MSG bind to a certain receptor (protein lock-and-key structure) called taste metabotropic glutamate receptor 4, truncated metabotropic glutamate receptor 1, or taste receptor 1 (T1R1) and T1R3 dimers that sit on the umami tastebud.

MSG is a pure form of a substance that our bodies usually see bound up in complex protein structures like the myofibrils in meat fibers. Because of this purity, it is absorbed extremely rapidly by our bodies (especially when it is in a liquid form, as so much of it is). When we are hit by a large bolus or amount of MSG, we experience excitotoxicity (not just some of us, all of us. Only certain people identify and correlate certain sensations to the ingestion of a bolus of MSG. Many of us are dosed continuously all day by low level exposures, leading to a near constant state of neuronal excitation). Another chemical which does the same thing and which is just as ubiquitous is aspartate (nutra-sweet).

How MSG is bad for us

Early on (in the 50s) studies reported significant issues relating to the exposure of mammals to MSG. If neonatal rats were given a single exposure to MSG, the neurons in the inner layer of their retina were killed. It was also reported that certain parts of their brains were injured as well (the hypothalamus). When considering various findings of MSG exposure in the rat, remember that humans are some 5-6 times more sensitive to MSG than rats.

At one point, researchers determined that rats would be an excellent model for the study of obesity after the exposure to MSG. MSG is a chemoinducer of obesity, type II diabetes and metabolic syndrome X in the rat. (lesion of the ventromedial hypothalamic nucleus (VMH) by administering monosodium glutamate) Thus, MSG is used in the lab to induce obesity in rats.

There is evidence that MSG disrupts the endocrine relationship between meta-thermoregulatory modulators like Neuropeptide Y (NPY) and leptin and their target tissue, brown fat. What this means is that MSG reduces the thermogenicity of brown fat while also suppressing food intake (hypophagia).

What this means on a practical level is that MSG will make you gain weight even as you decrease your caloric intake (these animals were not put on a diet, they chose to eat less).

If you ever say to yourself, “I hardly eat at all but I STILL gain weight,” you are not imagining things.


It is not an exaggeration to say that MSG is a cornerstone ingredient that makes our modern food industry possible. There are many more topics related to MSG that I have not covered here, but the few that I did cover should be enough to prompt most readers to learn more about MSG. I, for one, am going to give an MSG-free diet a try for our whole family. We have some pretty serious ADD dynamics happening for us, and it will be interesting to see if the reduction and perhaps eventual elimination of MSG from our diets does us any good in terms of ADD symptomology.

Going MSG-free is an extremely daunting notion. The hidden use of MSG is growing explosively with every passing year. I personally feel, after having read various scientific papers and sites in preparation for this post, that our obesity (in my family) is in large part a result of a complex interplay between MSG, insulin, and other thermoregulatory and homeostatic hormones.

Its not enough to reduce calories (I know first hand on that) and its not enough to “eat right.” I am convinced, now more than ever, that its the casual and unnecessary doping of our foods with chemicals like MSG that has lead us into obesity.

I know that some people do not believe the concerns about MSG in our food. For those people, I suggest, as a start, take a look at this rss bibliography from Medline (regarding just MSG and obesity, unfortunately limited to just the first 100 citations) for references useful in understanding what science has known for some time, that MSG is not a benign food additive.

I appreciate that you have read this far and I look forward to any of your comments.

*Note to All: Let me first say that this is not a post about what I think you should eat. I respect that you make the decisions which you need to make. You have your own special needs and desires around food. I guess all I ask is that you consume this post with an understanding that I am simply trying to educate my readers about the science of Monosodium Glutamate. This is not a discussion about whether you have a “real” food allergy or sensitivity nor is it about whether you believe that there are even any such things as allergies or sensitivities. It seems that the food blog world has this odd fascination with debating whether: 1) there actually exist food allergies or 2) if they are simply sensitivities. This post is not about any of that.

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