There are 5 basic tastes: sweet, sour, salty, bitter, and ‘umami’. Monosodium glutamate or ‘MSG’ is a food additive responsible for the umami taste.
You may have heard of MSG being referred to as the ‘flavour enhancer”. This is because the umami taste tends to also enhance the palatability and overall flavour intensity of the food it is added to.
What is it?
Glutamate is one of the most commonly found amino acids in nature. It is in many common natural plant and animal foods. Just to name a few, this includes tomatoes, mushrooms, broccoli, fish, meat, cheese, and even human breast milk.
Glutamate is a non-essential amino acid. This does not mean that we don’t need it – it means that the human body can make glutamate itself if needed, as well as obtaining it from the diet. It is required for normal human physiological function.
The glutamate part of MSG comes from glutamic acid which is a common amino acid. Remember: amino acids are simply the building blocks of protein. All proteins are made up of strings of amino acids linked together.
Sodium is a mineral that is naturally found in food but can also be added in the manufacturing process. For example, combining sodium with chloride gives common table salt which we often add to our food. Other common foods containing sodium include Himalayan pink salt, sodium bicarbonate, and rock salt.
Monosodium glutamate is formed when the glutamate (from glutamic acid) attaches to a sodium mineral ion.
Neither glutamate nor sodium are inherently dangerous. But the Australian guidelines recommend adults eat less than 2,300 mg of sodium per day which is about equal to 6 grams of salt. The sodium in MSG does contribute to daily sodium intake.
Is MSG Dangerous?
Myths and stigma surrounding the safety of MSG consumption have been around for a long time. They typically stem from a condition called “Chinese Restaurant Syndrome” (CRS) or “MSG symptom complex”.
Over the last few decades, CRS has been reported to occur both anecdotally, and in a variety of studies in people consuming MSG. Symptoms such as weakness, flushing, dizziness, headache, difficulty in breathing, numbness, muscle tightness, and even syncope were common.
The available literature on MSG showing such negative side effects is usually completely irrelevant to how you would consume MSG. For example, some studies showing toxic effects have been done in animals, having rats eating up to 100g per kilogram of MSG per day for 45 days.
Eating 100g per kg for a 75kg person would mean eating 750 grams of MSG per day. We don’t even eat 750g of protein or carbohydrates per day (even when carb-loading), let alone 750g of a salty, sparingly used food additive.
The average intake in industrialised European countries is 0.3 to 1g per day. To put that in perspective a “large amount” of MSG for a human to consume would be 3g. This is many, many magnitudes of difference from toxic effects found in studies.
Based on the available high-quality scientific evidence, MSG is safe for all life-cycle stages without respect to ethnic origin or culinary background. Many claims of side effects are at levels irrelevant to human exposure. There has been no consistent evidence showing reactions to MSG differing from placebo.
To your body, the sodium and glutamate in MSG are exactly the same as those that could be found naturally in food. Meaning that your body doesn’t know if the glutamate came from a mushroom or a packet of Doritos.
How Much Is Too Much?
Food Standards Australia and New Zealand (FSANZ) have not set a limit on the acceptable daily intake on the basis of MSG having such low toxicity levels. The European Food Safety Authority’s acceptable daily intake (of 30mg/kg body weight/day) is deemed unattainable to reach when MSG is consumed at normal dietary levels.
However, too much sodium from salt in the diet has been linked with increased blood pressure and hypertension, a risk factor for cardiovascular disease, including stroke and heart attack.
So if you are required medically to limit your sodium intake, you should consider your MSG intake and its contribution to sodium intake.
There is some evidence linking MSG intake with obesity in certain populations. But this data is only observational – meaning it cannot be said that MSG is the cause, and the mechanism of action (why) MSG would cause obesity is not known.
One suggestion is simply that MSG enhances the taste of the food making it easier to overeat. This is something to be conscious of as it may lead to weight gain long-term.
On the other hand… there is also observational evidence showing there is no link between MSG and obesity.
How To Check For MSG In Food
In Australia, labelling laws state that packaged food must declare the presence of MSG, or any other flavour enhancers as ‘flavour enhancer’ followed by their name or number. MSG’s designated number is 621.
For example, MSG could be identified on an ingredients list as:
- ‘Monosodium glutamate’
- ‘Flavour enhancer (MSG)’
- ‘Flavour enhancer (621)’
Ingredient labelling also applies to other added permitted glutamate food additives. These have the food additive code numbers 622 – 625.
Keep in mind some foods don’t legally require labels. Food served in cafes or restaurants, or when glutamates and glutamate salts are naturally present in a food or food ingredients (e.g. in yeast extract, or hydrolysed vegetable protein (HVP), don’t have to be labelled or declare MSG.
Overall, MSG is well regarded as safe (and delicious) and as with most foods/food components, MSG almost certainly falls into the realm of ‘some is fine, don’t overdo it’.
MSG and Food Chemical Intolerances
(Update July 2021)
Glutamate (and MSG) may also fall under the classification of ‘food chemicals’ or ‘food additives’.
Food chemicals are not as villainous as they may sound. Broadly, a food chemical/additive is “any substance added to food to maintain or improve its safety, freshness, taste, texture, or appearance”.
Even proteins are just chemical compounds of carbon, hydrogen, oxygen, and nitrogen…
Food additives have been around forever and even include simple things like salt and sugar that we use in curing or drying meats, pickling or fermenting vegetables, and making preserves. In winemaking, sulphur dioxide is added to prevent oxidation and inhibits the growth of bacteria and yeast.
So simply saying a food chemical is bad because of the stigma around words like “chemical” or “additive” is not a good practice. The Joint FAO/WHO Expert Committee on Food Additives (JECFA), is the international body responsible for evaluating the safety of food additives and they undergo rigorous examination before being declared safe and legal to use in food production.
However, this may not mean that certain individuals won’t experience a response from food chemical exposure.
The concept of food chemical sensitivity or intolerance is not new, (with studies exploring their effects dating back to the 1970s). The Royal Prince Alfred Hospital (RPAH) created an elimination diet as a way of diagnosing and managing food chemical intolerance in an individual.
Naturally occurring glutamate in foods (such as tomatoes, spinach, grapes, mushrooms, peas), and by extension, the glutamate in MSG, is listed as a food chemical to eliminate during the initial phase of the RPAH’s elimination diet (also sometimes referred to as the Failsafe diet).
In relation to MSG specifically, the RPAH’s own research states that “isolated MSG intolerance was rare” in the populations studied at the RPA hospital, and that:
“From the MSG questionnaire it was concluded that the population knowledge about the nature of MSG was incomplete and in many instances incorrect. Furthermore, people who self-report MSG intolerance often do not have a clear grasp of what MSG is and in which food products it is present.”
I would cautiously interpret this data, along with the weight of existing literature, and advice of international bodies governing the safety of food chemicals and their use – to indicate that ‘MSG is safe and tolerable at normal levels, and that in general people don’t even know what it is, let alone if it is causing them symptoms or not…’
If you are convinced that glutamate or MSG may be causing you symptoms, working with a dietitian experienced in implementing the RPAH elimination diet would likely be the best avenue to address this.
One final quote from a 2020 paper “A review of the alleged health hazards of monosodium glutamate” published in Comprehensive Reviews in Food Science and Food Safety states in summary:
Critical analysis of existing literature, establishes that many of the reported negative health effects of MSG have little relevance for chronic human exposure and are poorly informative as they are based on excessive dosing that does not meet with levels normally consumed in food products.Zanfirescu, A., Ungurianu, A., Tsatsakis, A. M., Nițulescu, G. M., Kouretas, D., Veskoukis, A., Tsoukalas, D., Engin, A. B., Aschner, M., & Margină, D. (2019). A review of the alleged health hazards of monosodium glutamate. Comprehensive reviews in food science and food safety, 18(4), 1111–1134. https://doi.org/10.1111/1541-4337.12448