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Monday’s medical myth: MSG is a dangerous toxin

Monosodium glutamate (MSG) is widely viewed as a dangerous food toxin that is responsible for adverse reactions to Chinese food and other meals. But is it really the MSG that’s to blame? Glutamate is a…

90% of the glutamate in our diet comes from protein, not MSG. Kevin H

Monosodium glutamate (MSG) is widely viewed as a dangerous food toxin that is responsible for adverse reactions to Chinese food and other meals. But is it really the MSG that’s to blame?

Glutamate is a naturally occurring amino acid, used chiefly in our body to make protein. Most of us normally eat around 10 grams of glutamate every day, much of which is released into the body when we eat and digest protein. Some protein-rich foods – such as meat, fish, chicken, dairy products, legumes and corn – are especially rich in glutamate.

But glutamate has another important property: it tastes good. When glutamate touches the taste receptors on our tongue, it gives food a savoury taste (known as unami). Mixed with our meal, glutamate is said to balance, blend and enhance the total perception of flavour. But not just any glutamate; we can’t taste glutamate that is locked in protein. For it to tickle our taste buds, it must be in a “free form”.

Some (tasty) foods – tomato products, fermented soy/fish/oyster/steak/Worcestershire sauces and long-matured cheeses such as stilton and parmesan – are high in free glutamate. Ever wonder why parmesan makes the bolognese taste better (and more meaty)? It’s the glutamate!

Jason Sandeman

Because MSG has such a bad name, many manufacturers use other sources of glutamate to give processed foods the extra taste. These include vegetable, corn, yeast or soy protein extracts, in which the glutamate has been released from the protein by enzymatic digestion or chemical hydrolysis. When dissolved in water, the free glutamate in these extracts is chemically identical to that contained in MSG and enhances flavour in precisely the same way.

Most of us would usually eat around half to one gram of free glutamate every day as additives to our food. In Asian countries, this figure is double, reflecting the use of soy and other fermented products in cooking. A highly-seasoned banquet in a Chinese restaurant may contain up to four to five grams of free glutamate.

But glutamate isn’t just found in Chinese restaurants. Many American-style fast foods contain just as much glutamate to enhance their flavour and your experience, beyond that of their competitors. Even Vegemite contains 1.4% free glutamate.

A burger and chips might contain as much MSG as you’d eat at a Chinese restaurant. Jaryl Cabuco | Fitted.Life

A small proportion of people experience transient symptoms when they consume large amounts of free glutamate (more than four to five grams) in a single meal. These reactions vary from person to person but may include headaches, numbness/tingling, flushing, muscle tightness and general weakness.

A number of scientific studies have tried to replicate this experience. Most have been too small, used unrealistically high doses of MSG, and were not undertaken in the context of food (or even with intravenous doses). Try eating a whole jar of Vegemite in one sitting and you will soon see why people don’t feel so well afterwards.

More rigorous studies have failed to confirm a reproducible response to meals containing MSG, even in self-attributed “MSG sensitive” individuals. Most reactions to a Chinese banquet probably have little to do with the MSG, as many of the same people who are “MSG sensitive” have no problems with Vegemite or parmesan cheese.

Foods such as peanuts can trigger asthma attacks but there’s no evidence that MSG has the same effect. EuroMagic

It has also been suggested that MSG can trigger an asthma attack. While there are lots of anecdotal reports (again, usually after Chinese food), challenge studies with MSG-rich meals have generally failed to confirm these findings. There are many other things in food that can trigger an attack in sensitive individuals, from dairy products, eggs, peanuts and sulphites, to food colourings. But none are vilified like MSG.

Finally, it has also been suggested that MSG leads to weight gain and obesity. Of course we have a great tendency to eat more of anything that tastes better, so this comes as little surprise. MSG has even been used to promote the appetite of frail elderly people.

The consensus among clinicians and scientists is that MSG is safe for human health. Very high doses may affect some people for a short time but there may be far more dangerous consequences that come from overeating this Christmas.

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13 Comments sorted by

  1. Grendelus Malleolus

    Senior Nerd

    After hearing tales from friends of their sensitivity to MSG I did a little reading and came to the conclusion it was based on self-perception rather than a genuine reaction to a naturally occuring molecule.

    Thanks for doing some further background to confirm this!

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    1. rob alan

      logged in via email @orakk.net

      In reply to Grendelus Malleolus

      My brother has a child with celiac disease which is most certainly due to self-perception. In my group of friends alone I know of three other kids have abstained from 'Free Gluten' products in diet and doing much better now.

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  2. Daryl Deal

    retired

    That is an easy answer, at "Hill&Knowlton style storm in a tea cup saucer over MSG"!

    One merely has to look more closely, to find out which of the then emerging fast food "super size me" bland nondescript trans fat tasteless food franchise chains benefited immensely both in the US and world wide from the fall and demise of all the local privately owned and operated family Chinese/Asian Fast Food restaurants of the same era. We tend to forget that the Mcdonalds Fast Food Chain began a small franchise operations in 1955, and for most of the sixties operated at a limited number of stores! In addition KFC in 1960, only had 600 stores nationwide in the US.

    The oldest story in the book, as Cicero would say "Who Benefits?"!

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  3. Diane Lester

    logged in via Facebook

    MSG is, I believe, often sourced from wheat gluten. Allergies to wheat are increasing, as is gluten intolerance, otherwise known as celiac disease, and its possible people react to the wheat proteins rather than the MSG itself.
    Besides, wheat gluten is widely used to generate glutamate which is then used widely for food flavouring purposes. This is annoying for celiac disease patients because it is often added to otherwise gluten-free foods (eg potato chips). Gluten is a byproduct of the wheat…

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    1. Ben Moore

      Lecturer, Hawkesbury Institute for the Environment, University of Western Sydney

      In reply to Christopher G. Baker

      MSG is generally not sourced from wheat gluten but by bacterial fermentation, and even if the MSG were to have been sourced from wheat protein, after the required hyrdolysis, there would be no intact protein and we should not expect to see a response equivalent to that promoted by gluten. Gluten intolerance is not synoymous with Coeliac disease, the former includes a broader range of conditions. As the author points out, glutamate is a commonly occurring and unvoidable dietary amino acid and its dietary origin should not affect its fate in our bodies. Diane raises a reasonable question in asking whether other glutamate-containing food additives might promote reactions in some people, however if this is the case, it is not glutamate that is the problem.

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  4. Mark Smith

    logged in via Facebook

    My six year old son had his first asthma attack on the weekend, a few hours after eating some (delicious) barbecue pork and duck- a common experience among asthmatics with whom I've since spoken. I too would like a response to Diane, if possible.

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  5. Emma Anderson

    Artist and Science Junkie

    Things I agree with, based on what I've observed so far:

    1. Glutamate is a naturally occurring and very common food chemical that does play an important (and essential) role in normal bodily functions
    2. Some of the stories out there on the internet over hype the dangers of glutamate, or at least don't support their assertions adequately.

    However, this article was biased. Firstly, because it focused on the lack of replication of a result without clearly acknowledging the broader complexities…

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  6. Pauline Aw

    Retiree

    Its a shame that this article only serves to diminish perceptions of the validity of physiological reactions to MSG in patients.
    People suffering from a sensitivity to this common food additive find nothing MYTHOLOGICAL about it at all! The foods that contain MSG are very wide (as are the range of symptoms), and include many fast foods, instant noodles, sauces, marinades, savoury biscuits and chips, as well as Chinese food. How many people eat yummy instant noodles and then take 2 panadol or ibuprofen…

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    1. Cecily Arman

      Business owner

      In reply to Pauline Aw

      MSG is a dangerous toxin TRUTH
      Pauline you are so correct. I am very surprised this was written by someone at a Heart Institute! MSG and free glutamic acid makes my heart race over 200bpm, (I have several reports at Emergency and cardiograph reports to show this if you do not believe me.) Verapamill only works somewhat to try stop this from happening to me. Not to mention many other terrible reactions to msg. Ie headaches, severe tension, restricted breathing, brain fog. Don't tell me it's not toxic…

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  7. Comment removed by moderator.