Food Science

What Is Monosodium Glutamate?

Japanese scientist Kikunae Ikeda wondered what gave a simple bowl of seaweed soup, kombu dashi, its meaty flavor. Kombu dashi is a ubiquitous Japanese soup base that is widely used to add extra oomph to meals. It is made from boiled seaweed and dried fish, and chefs paired it with meat and other savory dishes. But kombu dashi didn’t pair well with meatless foods like vegetables and soy.

It was in 1908 that the extremely determined Kikunae Ikeda was able to isolate the seaweed Laminaria japonica, the main substance of kombu dashi. He ran it through a number of chemical experiments. He used evaporation to separate a specific compound inside the seaweed. After several days of treating and evaporating, he noticed the development of crystalline form that had the distinct savory taste of kombu dashi. Kikunae Ikeda had changed the food industry forever. He had successfully isolated the distinct taste that kombu dashi gave to other savory foods, a taste that he deemed umani. 

Umami comes from the Japanese term ‘umai’ which means delicious. It became a breakthrough in the culinary world in 1908 and became the new frontier of taste along with salty, sweet, sour, and bitter. The fifth basic taste umami was described as savory, earthy, or meaty. It is known for its distinctive taste and the property of imparting depth and fullness to other flavors. As per the scientists, there are seven tastes, but there are five basic tastes that the tongue is sensitive to. 

Kikunae Ikeda determined the molecular formula of the crystals to be the same as glutamic acid, which makes up 10 to 25 percent of all food protein from both animal and plant sources. Furthermore, glutamate occurs as a natural part of a protein, which when broken by cooking, releases free glutamate. He started mass producing glutamate from fermented vegetable proteins, and called it ‘Ajinomoto’ meaning ‘essence of taste.’ Ajinomoto, the sodium salt form of glutamic acid, became famous for its ability to naturally enhance the flavor of food and is widely known as monosodium glutamate (MSG).

What Is Monosodium Glutamate? 

Monosodium glutamate, commonly known as MSG, is a flavor enhancer. MSG is a white crystalline powder that resembles table salt or sugar and is used mainly in the preparation of Chinese and Japanese food and various canned foods. Monosodium L-glutamate and sodium glutamate are some of its other names.

MSG is not regulated as a food additive and is considered a flavor-enhancing ingredient. MSG is added to food for its umamiu qualities. MSG is neither salty, nor sweet, sour, or even bitter. Yet it provides a savory flavor to the dish it is supplemented with. Simply put, MSG is added to any savory dish to enhance its taste and flavor. The sodium content in MSG is lower than in table salt. Another reason why MSG is added to food is to reduce the sodium content in it, especially in processed foods.

Foods Containing MSG

Monosodium glutamate is added to many commercially produced food items like:

  • Flavored chips and crackers, especially cheese-flavored
  • Instant noodles
  • Canned soups
  • Instant soup and dip mix
  • Seasoning salt
  • Salad dressings
  • Bouillon cubes
  • Pre-made gravies or gravy mixes
  • Hot dogs, including the soy-based vegetarian hot dogs
  • Cold cuts

Any packaged food containing MSG will explicitly mention it in the package. If MSG is not added, it doesn’t mean that the food item does not contain glutamate. It can be in the form of tomato, mushroom, or any other natural ingredient. 

MSG was extracted from seaweed broth until recently. Now it is extracted and crystallized from seaweed broth, as well as produced by the fermentation of sugar beets, starch, sugar cane, or molasses. 

The Relationship Between MSG and Your Body

Monosodium glutamate is simply a combination of sodium and glutamate. Glutamate occurs naturally in the body as glutamic acid, which is an amino acid that is voted as non-essential because the human body is able to produce it on its own. In the body, glutamic acid is found as glutamate, an anion and a different compound with one less hydrogen atom. The stomach lining and the gut in the human body are rich in glutamate receptors. They absorb MSG and other forms of glutamate through interaction with these receptors, which are incorporated into other molecules or broken down to act as a fuel.

Glutamate plays a crucial role in learning and memory, as it is one of the most abundantly found excitatory neurotransmitters in the brain. As they are naturally found in plant and animal sources, an average human consumes about 13 grams of it in a day from the protein in food.

What Is MSG Symptom Complex?

Monosodium glutamate has been used to enhance the taste and flavor of food for several years. But over the years, several health concerns were raised as adverse reactions to food containing MSG. These adverse effects or reactions are known as MSG symptom complex and include the following:

  • Sweating
  • Flushing
  • Headache
  • Nausea
  • Weakness
  • Chest pain
  • Facial tightness or extreme pressure
  • Heart palpitations or rapid fluttering heartbeat
  • Tingling, burning, or numbness in the face, neck, and other areas

There is no definitive evidence or link between these symptoms and MSG. Some people may experience short-term reactions to MSG, but these reactions are not life-threatening. 

Side Effects of MSG

MSG is a popular ingredient that is widely used in Asian cooking as a seasoning. The crystalline white powder is sprinkled into the dish to increase its tasty and savory taste. Though it is generally recognized as a safe ingredient, there are some side effects associated with its consumption, which include the following:

  • Leaky gut problem: The ingestion of MSG can cause inflammation of the small intestine, which in turn leads to a leaky gut problem. Some of the symptoms of leaky gut include bloating, diarrhea, gas, and abdominal pain.
  • Headaches: The link between MSG consumption and headaches, including debilitating migraine headaches, is inconclusive. Some researchers suggest that the risk of migraines have no links to MSG, while others believe that MSG can cause headaches. MSG was struck as a causative factor for headaches in 2018 by the International Headache Society.
  • Reduced salt consumption: When you use MSG as a seasoning, you tend to add less salt, as MSG enhances the savory taste. It reduces the sodium level, while maintaining the taste. Reduced use of salt can lead to low blood pressure. Though MSG is a major tool in reducing the use of sodium, it has an adverse effect on health.
  • Other health effects: MSG is associated with other side effects that include rapid heartbeat, skin rashes, excessive sweating, lethargy or sleepiness, intense thirst, ringing ears, nausea, and dizziness, among others. 

Why Is MSG Considered Harmful? 

Glutamate, the anion of glutamic acid, is a recognized excitatory neurotransmitter, which means that it inspires the nerve cells to transmit its signal. A few people believe that consuming MSG paves the way to unwarranted glutamate in the brain, which can lead to increased stimulus of your nerve cells. Considering this as a reason, monosodium glutamate is categorized as an excitotoxin.

MSG has been considered harmful, and this fear dates back decades ago to 1960s, after a study on newborn mice concluded that it possesses damaging neurological effects. The fear is kept alive since then by Excitotoxins: The Taste That Kills, a book by Russell Blaylock, and many such books and articles. 

Increased consumption of glutamate can indeed be harmful. Increased glutamate in the brain can result in brain damage. Additionally, it can also increase the blood sugar levels, causing several other health problems, such as diabetes, and obesity, among others.

It is important to note that dietary glutamate has little to no effect on the brain, as the blood-brain barrier cannot be crossed in great numbers. Furthermore, there is no convincing indication that shows that monosodium glutamate does what an excitotoxin can do, especially when it is consumed in standard acceptable amounts.

Is MSG Harmful?

Over the last fifty years, there have been several cases of adverse effects of MSG. But there is no scientific evidence to support the claims that MSG has any adverse effects, considering the amount that is consumed by the general population. 

Certain people may experience some adverse effects of MSG, a condition called MSG symptom complex. The symptoms occur if an individual consumes more than the average daily intake. The minimum dose that needs to be consumed for the symptoms to be seen is about three grams per meal. Three grams is nearly six times the normal or average daily intake that is advised in the U.S. and hence a very high dose. 

Researchers theorize that, when you consume food with high amounts of MSG, it enables small and significant amounts of glutamic acid to pass the blood-brain barrier. When this happens, glutamic acid interacts with the neurons in the brain and leads to brain injury and/or brain swelling. Apart from this, there are also claims that MSG can cause asthma attacks. About 40 percent of the people who were a part of a study suffered an asthma attack when they consumed a large amount of MSG. Yet again, these claims do not have any scientific evidence backing them.

It is unclear why a few people are affected by MSG, even if their consumption is lower than the average daily intake. Hence, experts advise that if you have experienced these symptoms, it is ideal to avoid any food that has MSG content in it. You may also want to limit the intake of food that has glutamates either as an additive or natural glutamate in vegetables and other food products.

Impact of MSG on Your Health

It has already been established that MSG consumed in large doses can have a possible adverse effect on health. But as there are no pieces of evidence to support any of the claims, the health concerns cannot be fully supported. Each claim is differing from the other, and it depends on the health and wellness of the individual, their age, the amount of MSG consumed, and any preexisting health condition. But there are some effects of MSG that can affect each and every person who consumes it. The impact of MSG on your health includes the following:

  • Impact on calorie intake: Some foods make you feel fuller than others, and when consumed, you decrease the calorie intake, which in turn aids in weight loss. MSG is believed to help in weight loss, as it makes you feel satiated. Some pieces of evidence support this claim. It is said that certain people who drink soups that have MSG added consume fewer calories in their subsequent meals. The umami flavor stimulates the taste receptors on the tongue and digestive tract and triggers the issue of the appetite-regulating hormones, which helps reduce the excessive intake of calories. Some studies also suggest that monosodium glutamate increases calorie intake, and hence, it is better not to depend on it to help you feel satiated and full. 
  • Impact on obesity and metabolic disorder: MSG is associated with increased weight gain as well. An animal study where MSG of high dosage was injected into the rats and mice brains resulted in them becoming obese. Some human studies also linked MSG to increased weight. A study conducted on Chinese adults resulted in an increase in weight, with an average intake of MSG that ranged from 0.33–2.2 grams per day. Another study was conducted in Thailand that resulted in weight gain in study subjects who consumed MSG. But as the study was flawed, it was criticized and considered void. In another study conducted in Vietnam, an average consumption of 2.2 grams of MSG per day was not linked with obesity or even being overweight. 

There is a need for extensive studies on the effects of MSG. There is insufficient evidence that can be tied to the claims that are made by the general public on the benefits and adverse effects of monosodium glutamate.

What Does the FDA Have to Say? 

The Food and Drug Administration of the United States has classified MSG as GRAS, or generally recognized as safe. MSG was initially extracted from seaweed. But now, it is produced by fermentation of carbohydrates, a process that is linked to the making of wine or yogurt, which is accepted by the FDA.

Over several decades, the FDA received several reports of symptoms, which include nausea and headaches, that occurred after consuming food added with MSG. As these claims were not backed with sufficient evidence, the FDA approached the Federation of American Societies for Experimental Biology, an independent scientific group to examine the safety of MSG. FASEB identified some generally mild, short-term, brief symptoms, such as numbness, headache, flushing, palpitations, tingling, and drowsiness in some sensitive individuals. These symptoms occurred in study subjects who consumed three grams or more of MSG without food.

How Is MSG labeled?

FDA requires manufacturers using MSG in foods to list them on the ingredient panel as monosodium glutamate. There is no limitation to the amount of MSG that can be added to commercially produced food.  But it must be consistent with GMP, or good manufacturing practice. GMP also requires manufacturers to list it on the label if it is further added to packaged food. It must be listed even when it is just a component of flavoring preparations, food flavor-enhancer preparations, spice mixtures, and any other mixtures or preparations. As per FDA regulations, all packaged foods containing MSG should clearly say so on the label. Hydrolyzed protein, sodium caseinate, and autolyzed yeast are ingredients that are pseudonyms for MSG and must be mentioned in the food label without fail.

MSG occurs naturally in ingredients such as hydrolyzed soy extracts, vegetable protein, hydrolyzed yeast, autolyzed yeast, yeast extract, and protein isolate, as well as in cheeses and tomatoes. These products must be listed under the ingredient panel, but they need not be listed as MSG. Manufacturers need not list MSG on the label if it is found naturally in some of the ingredients used.

Claims such as ‘No Added MSG,’ ‘No MSG Added,’ and ‘Contains No MSG’ are considered misleading and deceptive if the product contains MSG that occurs naturally. These claims cannot be made if the food product contains sources of free glutamate such as hydrolyzed soy protein (HSP), hydrolyzed plant protein (HPP), hydrolyzed vegetable protein (HVP), soya sauce, and such. If you are allergic or sensitive to MSG, then you should be vigilant for these kinds of naming conventions.

Several common food ingredients have high levels of free glutamate that include grapes and grape juice, tomato and tomato puree, some fruit juices, Parmesan and Roquefort cheese, and mushroom. As per the FDA, labeling is not required for naturally-occurring free glutamates mentioned above.

How to Avoid Excessive Use

Besides the delicious Chinese food and other restaurant foods, MSG is also found in several food items, such as tortilla chips, potato chips, salsa, bottled salad dressings, frozen meals, and such. MSG is used in several packaged food and labeled under different names that can be misleading to common people. As a result, many people fail to reduce consumption. You can avoid excessive use of MSG by:

  • Be able to recognize the different ingredients that have MSG, even the naturally occurring free glutamates in food items.
  • Read the label on the packaged food item. The FDA has mandated that MSG must be mentioned in the ingredients if it is used in the production. By reading the label, you can avoid that food product. It will most likely be listed towards the bottom of the ingredient list.
  • Follow the guidelines and do not exceed the average daily intake. You do not require MSG to perk up the flavors of juices, candy, sweet baked goods, butter, and milk. There are only a few foods that benefit from the use of MSG, and maintaining the average daily intake cannot be difficult. The general guidelines allow no more than two milliliters per six servings of vegetables, or five milliliters, which is equivalent to one teaspoon of MSG, per kilogram of food.
  • Commercially produced foods with added MSG can be avoided, or if there is a need to consume it, make sure that you use it in moderation. Additionally, since pre-packed food contains monosodium glutamate, further seasoning with MSG is not required.

A Controversial Topic

For several decades, monosodium glutamate, commonly known as MSG, has been branded as unhealthy and suffered its consequences. Many people know it as a substance that is terrible for you. But is it? The controversy that surrounds the use of MSG in food is ongoing.

Several experts reject the claims made by people regarding the health effects as MSG, as it is nothing but sodium and glutamate, which is found naturally in several food items. The body has the capacity to digest naturally occurring glutamate that is present in everyday foods, like milk, mushroom, and cheese, among others. The body has the capacity to digest MSG seasoning the same way it digests glutamates in foods. 

As there is insufficient research studies that support any of the claims, it is difficult to conclude whether MSG is good or bad. Recently, a campaign called Redesign CRS was launched to change the misconception, misinformation, and public perception of MSG and Asian cuisine. The online campaign was launched and headed by Japanese food and seasoning company Ajinomoto, which hopes that it can change misconception on MSG from the minds of people. 

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