Is MSG Safe? – Part 1
Government agencies say it’s harmless. Critics claim it’s toxic. Who’s right?
Monica Reinagel, MS, LD/N, CNS
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Is MSG Safe? – Part 1
Several listeners have written with questions about MSG. Kayla wants to know exactly what MSG is and what foods it is found in. Miriam has read conflicting claims: that it causes migraines and other problems and that it’s a natural ingredient that has been proven to be safe. And Brooke wants me to address concerns about MSG in nutritional yeast and other “health” foods. .
There’s a lot to cover, so I’m going to tackle the topic in two installments. In this article, I’m going to take a look at what MSG is, how it acts in the body, how it’s used in the food supply. In Part 2 of this series, we’ll take a closer look at charges that MSG causes headaches (“Chinese Restaurant Syndrome”), neurological damage, or has harmful effects on insulin, diabetes risk, or even obesity.
What is MSG?
Let’s start with a quick overview of terms:
Glutamic acid is an amino acid—one of the building blocks of proteins. It’s naturally found in all living cells (both plant and animal) and is especially abundant in protein foods. Your body also produces its own glutamic acid. It’s particularly important to the brain, where it acts as a neurotransmitter. It also detoxifies the body and brain of ammonia. Some researchers are even investigating whether glutamic acid could be useful in the treatment of Parkinson’s disease, epilepsy, and other neurological conditions.
Glutamate is often used interchangeably with glutamic acid but, technically speaking, it refers to glutamic acid with a mineral attached to it. If that mineral is potassium, you’ve got potassium glutamate. If the mineral happens to be sodium, we call it sodium glutamate.
Free glutamate Most of the glutamate in foods is “bound” or linked with other amino acids to make up larger proteins. When glutamate is on its own, however, it has special flavor enhancing properties. (More about that in a moment.)
Monosodium glutamate (MSG) is a food additive used to enhance flavor in foods. It’s made up of free glutamate attached to sodium. It can be extracted from seaweed but most MSG is produced through bacterial fermentation.
Glutamine is another amino acid that sounds very similar to glutamate. And just to make it a little more confusing, the body readily converts glutamine to glutamic acid and vice versa. However, I include it in this list just to clarify that any information you come across that’s talking about glutamine has nothing to do with MSG.
Glutamate and Umami
For a long time, scientists recognized four distinct “tastes” corresponding to different taste receptors on the tongue: sweet, salty, sour, and bitter. However, in 2000, researchers found a fifth taste receptor on the tongue which responds specifically to free glutamate. The Japanese describe this unique flavor as “umami.” Here in the West, we say that foods high in free glutamate taste “savory” or “meaty.”
Free glutamate occurs naturally in foods; tomato juice, parmesan cheese, peas, grape juice, mushrooms, and soy sauce are all relatively rich in free glutamate. It’s also found in nutritional yeast, Bragg’s liquid amino acids, yeast extracts, and other foods that are often promoted as “healthy” condiments or flavoring agents. It’s the free glutamate, for example, that gives nutritional yeast its characteristic “cheesy” flavor.
Food manufacturers use MSG to heighten the flavor of foods like soups, stews, sauces, and—of course—junk foods. They also use other ingredients that are not MSG but are high in free glutamate, such as hydroloyzed pea or soy protein or autolyzed yeast. “Hydrolyzed” and “autolyzed” mean that the proteins in these foods have been broken down—by fermentation or enzymatic reactions—into individual amino acids, which releases, among other things, free glutamate.
The average person takes in about 1 gram of free glutamate a day, and about half of that is likely to be from MSG.
Beneficial Uses of MSG
Despite the fact that it makes foods taste better, we generally think of MSG as a bad thing. After all, who (besides Frito Lay) benefits when we make Doritos Chips more irresistible? But MSG can also be used for less dastardly purposes.
Elderly people and those being treated with chemotherapy often lose their sense of taste and smell—leading to decreased food and nutrient intake. MSG added to healthy foods like vegetables and soups can heighten the flavors and encourage patients to eat more, improving their nutrition status. Because it enhances the perception of other flavors, MSG can also allow chefs and food manufacturers to reduce the amount of sodium in a dish without sacrificing flavor.
Dangers of MSG
Of course, none of this matters if MSG is harmful. And, as Miriam points out, there are a lot of people out there convinced that MSG causes headaches, flushing, or other symptoms, and others who fear that MSG is an “excitotoxin” that can damage nerve cells and cause neurological problems. Some even claim that MSG may be responsible for the obesity epidemic.
Many feel that the mainstream medicine and government agencies have blown off their concerns about MSG. To the contrary, they appear to have taken the concerns quite seriously. Dozens of carefully controlled studies have been done to further investigate these charges and several governmental, non-governmental, and international agencies have commissioned independent panels to gather, review, and report on the evidence.
In Part 2, we’ll take a look at exactly what those studies found and who might want to avoid MSG and glutamate.
Tired of trying to figure out whether there are “healthier” food options at the supermarket? Check out my Grocery Store Survival Guide here: https://tinyurl.com/3rsroec
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About the Author
Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes’ most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation’s leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.