MSG
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 cases a common natural plant and animal food. 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 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 7.5 kilograms of MSG per day. In general, most of us don’t even eat 7.5kg of food per day (even when carb-loading), let alone 7.5kg of a salty, sparingly used food additive.
The average daily intake of MSG in industrialised European countries ranges from 0.3 to 1 gram. For context, consuming 3 grams of MSG would be considered a “large amount” for a person. This is significantly lower—by several orders of magnitude—than the levels associated with toxic effects observed in studies.
There have been comprehensive reviews and articles written on the safety and alleged hazards of MSG. They provide some great further information, but essentially:
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 medically required to limit your sodium intake, you should consider your MSG intake and its contribution to sodium intake.
Some evidence suggests a link between MSG intake and obesity in certain populations. However, this data is observational, meaning it cannot establish MSG as the cause, and the mechanism by which MSG could contribute to obesity remains unclear.
One suggestion is 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
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 inhibit the growth of bacteria and yeast.
Dismissing a food chemical simply due to the stigma surrounding terms like “chemical” or “additive” is not a sound approach. The Joint FAO/WHO Expert Committee on Food Additives (JECFA), the international authority responsible for assessing the safety of food additives, ensures these substances undergo rigorous evaluation before being deemed safe and approved for use in food production.
However, this does not rule out the possibility that some individuals may experience adverse reactions to 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:
I would interpret this data cautiously, considering the broader body of existing literature and the guidance of international authorities overseeing the safety of food chemicals. This suggests that MSG is safe and tolerable at typical consumption levels. Furthermore, most people are not even aware of what MSG is, let alone whether it could be responsible for their symptoms.
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