*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.
Introduction
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).
Synonyms/Euphemisms:
- 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.
Mechanism
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.
Conclusion
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.
Related Posts:
- Molecular Gastronomy 101: Biology Basics - Part 1
- Molecular Gastronomy 101: Part 2 – The Nose and receptors
What other food bloggers are saying:
- Tigers & Strawberries - Let’s Talk about MSG
- Tigers & Strawberries - Series on Umami
- Serious Eats
- The Ethicurian
Technorati Tags: New York Times, MSG, Kikunae, Ikeda, Tokyo Imperial University, chemistry, flavor, Monosodium Glutamate, Ajinomoto, patent, savory, food, mass marketing, ubiquitous, Prepared food, KFC, chicken skin, poultry, turkey, hamburger, Fruit, vegetable, euphemism, modified food starch, citric acid, corn, hydrolyzed, glutamic acid, neurotransmitter, neurons, excitation, myofibril, excitotoxicity, aspartate, hypothalamus, obesity, leptin, brown fat, thermogenicity, weight, cornerstone, food industry
13 comments for this entry ↓
1 Barbara // Feb 21, 2007 at 11:54 am
Excellent post, Nika! Thank you for taking the time to do the research and writing for it.
Going completely MSG free will be a difficult proposition, but if you are in the habit of primarily eating whole foods anyway, it should be easier for you than for someone who eats a lot of processed or fast foods.
Where do you stand on the use of naturally occurring glutamate ingredients? As you note in your post, these ingredients have the glutamates bound up in complex chemical chains; my feeling in that case is that they are quite probably safe and healthful to eat.
It really is sad that modern humans have essentially become a population of test animals for the food industry. We in the US are for the most part eating a diet which we did not evolve to eat. And it all happened so fast that our bodies have had no time to adapt.
Which is all very interesting from a theoretical standpoint; it rather sucks, however, to be in the midst of it.
I’m off to add a link to this post to mine about MSG…you did a great job!
2 Tigers & Strawberries » More on MSG and Glutamates // Feb 21, 2007 at 12:10 pm
[…] at Nika’s Culinaria, wrote an excellent well-researched post explaining the chemistry of MSG and the health implications for humans ingesting large quantities […]
3 Nika // Feb 21, 2007 at 3:16 pm
Barbara: So glad you liked it.
Re: eating whole foods - man its so hard because I am now going to have to interrogate Whole Foods to be SURE they do not use Auxigro…
For certain, I am going to be planting an even bigger garden this year. I need to also fast track our greenhouse project.. right now its still in the planning stages.
The scary part (one ok one of several) is the washing of carcasses and smaller fabricated meats with the Sanova.. I have already sourced a local farm that grows chickens and pigs like a CSA (they also do veggies) and we will be buying from them. I have to interrogate their butchering facility to see what they use (hope its not Sanova).
We also have a local organic beef farm and will be checking them out again.
I am going to have to get some new cookbooks on MSG-free cook to not make my own MSG
This is a long term project!
Re: naturally occuring.. I think its fine as long as its still in it’s complexed form but some of the things we do in the kitchen makes free MSG (i.e., chicken stock boiled for ages).
A raw macrobiotic diet with some retooling on the MSG containing veggies and protein sources is likely where one would have to go. THAT sounds hard!
4 Sally // Feb 22, 2007 at 9:18 am
GREAT post Nika! Thank you so much! I’ll be interested to read how you attempt making your life MSG free.
5 Nika // Feb 22, 2007 at 11:14 am
Sally: thanks! I will do an update at some later point on how its going. We have to do an MSG inventory on the foods we have right now and clean out the more offensive ones. It will be like a much harder version of the things we had to do when we found out that our oldest was severely allergic to nuts.
6 Kathryn // May 6, 2007 at 5:30 am
I checked out the PubMed link for the MSG-induced obesity. That paper had no abstract, but one of the “related study” links had one. The mice were injected with 3-10 mg MSG per gram of body weight. That’s a huge dose! That would be 3-10 grams of MSG per kilogram of body weight, which for a 50-kg human (about 110 lbs, a very small person) would be 150-500 grams of MSG. This just isn’t comparable to any imaginable dietary intake. Imagine taking a cupful of MSG (or salt, or any other seasoning) and eating it! Yeah, you’d probably feel pretty awful.
We can’t necessarily conclude that something is harmful at low levels, just because it is harmful at tremendously high levels. I’m not sure what your background is, but I’m studying toxicology in graduate school. A lot of laypeople don’t understand the basic principle that “the dose makes the poison.” There is no substance that is completely safe at all levels of intake, not even water or oxygen. Researchers can induce oxidative stress–damaging levels of free radicals–by administration of pure oxygen. But that doesn’t mean we can improve our health if we stop breathing oxygen. (It does, however, mean I’m not wasting my money at an oxygen bar unless I’m at high altitudes.)
There certainly are substances that are so toxic there isn’t a safe dose. However, I don’t expect glutamate is one of those because it is a component of all protein foods. Isolated and concentrated glutamate, as in MSG, could certainly raise the level into a toxic dose, but I don’t have time to do the research right now (finals week!). It would be interesting to compare the free glutamate levels in foods with naturally-occurring glutamate versus MSG-flavored foods. If common foods, such as tomato products, meats, etc. are likely to have similar glutamate levels to MSG-flavored foods, then the next step would be to see if those foods also cause the harm attributed to MSG. I am hesitant to label something so common as a Deadly Poison without a lot of evidence it is actually harmful at actual exposure levels.
On the other hand, if MSG is typically added to foods at levels 100-1000 times what is normally found in foods, I wouldn’t rule out toxic effects. Since the intent is to simulate natural flavors, I doubt the level is that high.
Do you intend to cut all sources of free glutamate out of your diet, or just MSG? There is a long list over at Strawberries and Tigers of common Western foods, such as tomatoes, mushrooms, and more (basically anything with a savory umami flavor) that are naturally high in glutamate.
This is a very interesting topic, and I wish someone had addressed it in my Biochemical Toxicology class or the Toxicology seminar I took last year. Most of my classmates are more concerned with environmental toxicology than human health hazards. My research is on the neurotoxic effects of copper, so I picked papers related to my own project.
7 Jonathan, Nashville,TN // Nov 5, 2007 at 7:06 am
I read the article (for the most part). I have found over the years how this food preservative affects me. When I eat food containing this msg, it seems like after it metabolizes in my bowels, after about 6-8 hours, it does something to my brain. For example, if I eat it before bedtime, I will wake from a dead sleep and feel agitated and never never fall back asleep until it leaves my body! I read the food labels and esp. look for msg. I can’t enjoy seafoods because most of them have the spicy seasoning, which of course has this toxic substance on it. It may be a “good” preservative, “flavor enhancer”, or whatever, but I hate that the FDA has the right to decide what is good and what isn’t. The only good foods are the ones designed for us by God himself - fruits and veggies and of course meat from animals.
8 Donna // Jan 16, 2008 at 7:05 am
Good article,
I would like to know your opionions on neurotransmition. How has your life sytle change (DIET) effected the ADD at home? I have been doing it, mostly, for going on 3 years.
My daughter now 8, has had a series of medical difficulties since birth. A couple years ago an MRI discovered several brain leasions and a Chiari malformation. Chiari in its simplest explanation is a herniated brain stem. No meds. could help. We were told from a Childrens hosp. in St. Louis, when the sypmtoms gets so bad that you feel it warrants brain surgery give us a call. It got bad enough that her quality of life was being effected by central nervous system related disorders, headaches, lethargic, memory loss, concentration, very bad disposition. She had become a different child before our very eyes. When the doctors said they could not help, I began to do my own research. I decided it was worth a try. With a black trash bag, I cleaned out my cabinets. There was nothing left. 4 days later, on Sunday afternoon, my daughter was returned to me, mind, body, and spirit. It is not easy, but it is worth it.
When she begs for stuff she cant have, like McD’s. I let her have it. Later that evening she has a headache, stomach ache, or grounded for attitude, and wishes she had not eaten it. My hopes are to teach her the natural consequence for her eating choices. One day she will not be at home and have to do her own shopping. I want her to remember what happens when she eats it and not how crazy mom was.
Thanks for educating people.
donna
9 mel // May 5, 2008 at 6:48 am
I have recently been affected by a reaction to a work uniform. They cannot find the reactive agent in the uniform but it has affected 200 of the employees at the organisation I work for. The allergy specialist we all attend believes that whatever the cause is, it has triggered our immune system into a hypereactive state. To cut a long story short - I have developed an allergy to MSG - not at all surprising given the information you have imparted! I have also developed allergies to several other foods. I have become extremely vigilant at checking food labels and not choosing anything with 621 of MSG listed but still having unexpected anaphylactic reactions and minor allergic reactions to various foods. Having read the list of euphamisms for MSG - I now understand this. Knowing this now, I realise how little I can eat from the supermarket and will have to prepare everything fresh at home.
Thanks for helping to decrease the amount of adrenaline and antihistamine I am requiring!!!!
Mel
10 n // May 5, 2008 at 7:07 am
mel: I am so sorry you are having such a hard time. Remember that cooking meats and some veggies a long time can also increase free glutamates so try to eat simple foods that are not cooked for long periods of time. Later, once your poor system relaxes a bit you can ease back into those delicious slow roasted meats and such. Same with mushrooms and tomatoes.
I had a massive allergic reaction once to penicillin and I had hives for a week until my doc gave me anti-hive meds - that let my body relax and step down from it’s immune overdive and then things evened out.
I hope you can get to a similar place. good luck!
11 Bonnie // May 12, 2008 at 4:09 pm
“If you ever say to yourself, “I hardly eat at all but I STILL gain weight,” you are not imagining things.”
If MSG causes weight gain, then why isn’t Asia in the middle of a huge obesity epidemic? They eat substantially more MSG than the rest of the world–for example:
“With respect to added GLU (glutamate), only limited data are available. In EU countries the mean intake ranges from 0.3 to 0.5 g/day; in Asian countries people consume in average 1.2–1.7 g/day.”
(from eur. j. clin. nutr. http://www.ncbi.nlm.nih.gov/pubmed/16957679?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum )
So Asians eat twice as much added glutamate as Europeans, yet they stay slim. This seems to contradict the idea that MSG is a major causative agent for obesity in the US and Europe.
12 nika // May 12, 2008 at 4:26 pm
Bonnie: Its important to understand the difference between epidemiological studies (which can be confounded in very complex and poorly understood ways) and mechanistic studies as I cited above.
Additionally, understanding the difference between anecdotal observations (a rather naive and factually incorrect belief “All asians are skinny”) and scientific inquiry and investigation is key for one to have a clear and critical understanding of any “fact” or study in Science.
The erratum you reference above is in itself cautious about the use of MSG with respect to exposure in those people with a compromised blood-brain barrier.
The role of MSG as a toxin is so well known it is used as a reagent in a variety studies (as mentioned above for the induction of obesity in rat models) and in particular studies on retinal disease - try this link where MSG is used as a reagent to induce retinal damage - http://www.ncbi.nlm.nih.gov/pubmed/18418735?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
For some odd reason the whole MSG thing is massively burdened by widespread cognitive dissonance.
I do not wish to convince you of anything you do not wish to see.
I would ask, as a scientist myself, that you use this as a teachable moment - learn more about MSG for yourself, keep an open mind.
13 nika // May 12, 2008 at 4:31 pm
Bonnie:
I thought I would share this study from Japan (birthplace of MSG).
Monosodium glutamate (MSG): a villain and promoter of liver inflammation and dysplasia.Nakanishi Y, Tsuneyama K, Fujimoto M, Salunga TL, Nomoto K, An JL, Takano Y, Iizuka S, Nagata M, Suzuki W, Shimada T, Aburada M, Nakano M, Selmi C, Gershwin ME.
Department of Diagnostic Pathology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Chronic inflammation is a common theme in a variety of disease pathways, including autoimmune diseases. The pathways of chronic inflammation are well illustrated by nonalcoholic steatohepatitis (NASH), which is of a serious concern due to its increasing prevalence in the westernized world and its direct correlation with lifestyle factors, particularly diet. Importantly, NASH may ultimately lead to the development of hepatocellular carcinoma. We previously reported that injection of monosodium glutamate (MSG) in ICR mice leads to the development of significant inflammation, central obesity, and type 2 diabetes. To directly address the long-term consequences of MSG on inflammation, we have performed serial analysis of MSG-injected mice and focused in particular on liver pathology. By 6 and 12 months of age, all MSG-treated mice developed NAFLD and NASH-like histology, respectively. In particular, the murine steatohepatitis at 12 months was virtually undistinguishable from human NASH. Further, dysplastic nodular lesions were detected in some cases within the fibrotic liver parenchyma. We submit that MSG treatment of mice induces obesity and diabetes with steatosis and steatohepatitis resembling human NAFLD and NASH with pre-neoplastic lesions. These results take on considerable significance in light of the widespread usage of dietary MSG and we suggest that MSG should have its safety profile re-examined and be potentially withdrawn from the food chain.
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