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Monosodium Glutamate: A Look at the Facts
Some Background on MSG
What is monosodium glutamate (MSG)?
MSG is a flavor enhancer that has been used effectively for nearly a century to bring out the best flavor in foods. It is comprised of the amino acid glutamic acid, or glutamate for short, sodium, and water. Glutamate is found naturally in protein-containing foods such as meat, vegetables, poultry, and milk. The human body also produces large amounts of glutamate. The muscles, brain, and other body organs contain about four pounds of it, and breast milk is richer in glutamate than cow’s milk.
Glutamate is found in two forms: "bound" glutamate (linked to other amino acids forming a protein molecule) and "free" glutamate (not linked to protein). Only free glutamate is effective in enhancing the flavor of food. Foods often used for their flavoring qualities, such as tomatoes and mushrooms, have high levels of naturally occurring free glutamate.
How long has MSG been used?
Over 1,200 years ago, Oriental cooks discovered some foods tasted better when prepared with a soup stock made from the seaweed, Laminaria Japonica. It was not until 1908 that Professor Kikunae Ikeda of The University of Tokyo isolated glutamate from the seaweed and unlocked the secret of its flavor-enhancing properties. Since that time, MSG has been, and continues to be, widely used as an effective means of making good food taste better.
How is MSG made?
MSG is usually produced through fermentation — a process similar to that used in making vinegar and yogurt. The process begins with the fermentation of corn, sugar beets, or sugar cane. The finished product is a pure, white crystal, which dissolves easily and blends well with many foods.
Using MSG in Foods
How does MSG enhance food flavor?
Cooks around the world have always known certain foods have more distinct and pleasurable flavor characteristics than others; that is why these foods often are used as ingredients in recipes. It has been noted that glutamate is an important element in the natural ripening process, which results in full flavor. Perhaps this is why foods naturally high in glutamate (such as tomatoes, cheese, and mushrooms) are often used for their flavorful qualities.
MSG enhances the basic flavor of many foods. New studies also show MSG elicits a unique taste known as "umami" in Japan and often described by Americans as a savory, broth-like, or meaty taste. "Umami" has been identified as the fifth primary element of taste — in addition to salty, sweet, sour, and bitter. As an integral part of cuisines around the world, this savory taste is common to the bouillons of Europe, the oyster sauce of China, the soy and fish sauces of southeast Asia, the pizza and lasagna of Italy, and the chowders and stews of America.
How is MSG used in cooking?
MSG helps bring out the best natural flavors in a variety of foods such as meat, poultry, seafood, and vegetables. Soups, casseroles, gravies, and sauces are examples of dishes that can benefit from the proper use of MSG. While MSG harmonizes well with salty and sour tastes, it contributes little or nothing to sweet or bitter foods.
Results of taste panel studies indicate a level of 0.1 to 0.8 percent MSG by weight in food provides optimum enhancement of the food’s natural flavor. This is within the range of glutamate that naturally occurs in foods. Approximately one-half teaspoon of MSG is an effective amount to enhance the flavor of a pound of meat or four to six servings of vegetables, casseroles, or soup.
MSG is a self-limiting substance — once the proper amount is used, adding more contributes little, if anything, to food flavor. Overuse of MSG, as with many other seasonings and spices, may cause some foods to have an undesirable taste. There is simply no substitute for wholesome, quality food and good cooking techniques. MSG makes good-quality food taste better, but will not improve the flavor of poor-quality food.
Is the glutamate in MSG the same as the glutamate in Parmesan cheese or mushrooms?
It does not matter whether you select glutamate-rich foods and ingredients, like tomatoes, Parmesan cheese, walnuts, MSG, or soy sauce; the glutamate in each is the same.
Medical specialists have known for decades that your body does not distinguish between the glutamate found naturally in foods and that in MSG. In fact, even today’s state-of-the-art technology can’t separate them. For example, if you analyzed a plate of spaghetti you could identify the total amount of glutamate in the dish. However, there is no way to determine whether the glutamate came from tomatoes, Parmesan cheese, or MSG.
| Free Glutamate Content of Foods |
(mg/ml) |
| Cow’s milk |
2 |
| Human milk |
22 |
| Eggs |
23 |
| Beef |
33 |
| Fish (mackerel) |
36 |
| Chicken |
44 |
| Potatoes |
102 |
| Corn |
130 |
| Oysters |
137 |
| Tomatoes |
140 |
| Broccoli |
176 |
| Mushrooms |
180 |
| Peas |
200 |
| Grape juice |
258 |
| Fresh tomato juice |
260 |
| Walnuts |
658 |
| Soy sauce |
1,090 |
| Parmesan cheese |
1,200 |
| Roquefort cheese |
1,280 |
How much MSG does an average person consume?
The glutamate added to foods for flavor, in the form of MSG, represents only a small fraction of the total amount of glutamate consumed in the average daily diet. The average person consumes around 10 grams of bound glutamate and up to one gram of free glutamate daily. The human body creates about 50 grams of free glutamate daily. In contrast, the added intake of free glutamate through MSG amounts to approximately one-half gram per person, or one-tenth of a teaspoon daily.
Does the body metabolize added MSG any differently than naturally occurring free glutamate in food?
No. According to The Federation of American Societies for Experimental Biology (FASEB), there is no difference between naturally occurring glutamates and added glutamates in the way they are metabolized. Additionally, scientific authorities from around the world, including the U.S. Food and Drug Administration (FDA) and the American Medical Association (AMA), agree the body handles glutamate in the same way regardless of its source. All glutamate is absorbed in the intestine and follows normal metabolic pathways.
As a result of consuming MSG or protein-based foods, a natural elevation of the blood glutamate level will occur. That level will return to "baseline" (or the level before eating) in about three hours, no matter what the source of glutamate.
In fact, a research team from National Taiwan University observed plasma levels of glutamate following the consumption of large dietary sources of MSG in meals. The researchers concluded that the rather low plasma glutamate concentrations over the 24-hour period, despite the high intake of MSG, "indicate that dietary MSG is metabolized very rapidly."
How much sodium does MSG contribute to foods?
MSG’s low sodium content represents a minor contribution to the overall sodium level of a typical diet. By way of comparison, MSG contains about 12 percent sodium, while table salt contains 39 percent. And, MSG is used at levels much lower than salt. Considering all sources of dietary sodium (natural sodium content of foods, table salt, sodium-containing ingredients in processed foods, drinking water, and pharmaceuticals), typical use of MSG contributes about 1 percent to 2 percent of the total sodium contained in the average daily American diet.
Taste tests have shown when the salt level in food is reduced, food acceptability decreases. However, by using a small amount of MSG in conjunction with a decreased level of salt, sodium intake can be reduced by as much as 30 percent to 40 percent, while maintaining an acceptable flavor profile.
MSG Nearly a Century of Safe Use
Is MSG safe?
Yes. MSG has been used for nearly a hundred years and is one of the most thoroughly researched food ingredients. Its extensive database of hundreds of peer-reviewed studies has undergone intensive scrutiny, and MSG’s safety has been confirmed time after time in reviews of this data. For more than four decades, the FDA has repeatedly confirmed MSG’s safety. MSG is so safe the FDA has placed it on the list of substances known as "Generally Recognized as Safe" (GRAS), right along with sugar, baking powder, salt, and pepper. Likewise, the World Health Organization (WHO) has chosen not to set a limit on Accepted Daily Intake (ADI) of MSG, classifying it as "not specified," the safest category for a food additive.
What other organizations have declared MSG to be safe?
Scientific and regulatory bodies from around the world have reviewed and repeatedly confirmed MSG’s safety. These include the following:
| Organization |
Year |
| Food and Drug Administration (FDA) GRAS status |
1959 |
| Federation of American Societies for Experimental Biology (FASEB) |
1980 |
| Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) |
1987 |
| European Union Scientific Committee for Food (SCF) |
1991 |
| American Medical Association (AMA) |
1992 |
| Federation of American Societies for Experimental Biology (FASEB) |
1995 |
Is MSG safe for infants and pregnant women?
Yes. Extensive research shows MSG is safe for all humans, including infants and pregnant women. Infants, including premature infants, metabolize glutamate as efficiently as adults.
Studies have shown dietary glutamate is not transferred from mother to fetus; in other words, it does not cross the mother’s placenta. Research conducted by Dr. Battaglia at University of Colorado Health Sciences Center even showed the placenta actually takes up glutamate produced in the fetal system and empties it into the mother’s system.
MSG also is safe for nursing mothers. The glutamate concentration of breast milk does not increase after consuming large quantities of MSG. You might find it interesting to note the glutamate content of breast milk is naturally about 10 times that of cow’s milk.
Despite popular misconception, U.S. baby food manufacturers voluntarily stopped using MSG in baby food. Concern about ingredients such as salt, sugar, and other food ingredients prompted the industry to voluntarily withdraw these ingredients from baby food three decades ago.
MSG and Health-Related Claims
What about any impact MSG might have on the central nervous system?
In its 1995 review, the Federation of American Societies for Experimental Biology (FASEB) clearly stated there is no evidence to suggest MSG causes any adverse effects on the central nervous system. The FDA reached the same conclusion upon review of the data, which has shown:
a.) Glutamate (either added to food as MSG or as a naturally occurring component of the food) is rapidly metabolized in the intestines
b.) Blood glutamate levels do not rise to any appreciable degree after the ingestion of foods containing added MSG
c.) The blood-brain barrier restricts the flow of glutamate into the brain
The blood-brain barrier is a selective barrier designed to protect brain cells. It is important to note, the brain actually makes its own supply of glutamate because it is essential for brain function.
Does MSG induce asthma?
No. The FDA, as well as scientific and regulatory bodies around the world, agrees that MSG does not cause or exacerbate asthma. Extensive research in the United States has repeatedly failed to document any link between MSG and asthma, including studies at The Scripps Research Institute, the National Institutes of Health (NIH), Harvard Medical School, and Beth Israel Hospital.
A study published in the August 1999 Journal of Allergy and Clinical Immunology showed that consuming food containing MSG does not induce signs or symptoms of asthma. Conducted at The Scripps Research Institute, the study included 100 participants, 30 of whom reported asthma attacks after consuming MSG. The study showed no link between MSG and asthma and helped participants to identify other causes, including food allergies and heartburn caused by overeating.
Has research shown that MSG causes migraine headaches?
No. Migraine headaches are severe, often debilitating headaches. While there are many theories about what causes migraines, such as heredity, neurological brain disorders, and blood vessel disorders, there are no double-blind, placebo-controlled studies linking MSG to migraines.
Are some people sensitive to MSG in foods?
The scientific evidence does not support the existence of a sensitivity to MSG in foods. The November 2000 Journal of Asthma, Allergy and Immunology published research from a multicenter, multiphase study conducted by researchers at Harvard University, Northwestern University, and the University of California, Los Angeles. This double-blind, placebo-controlled study included subjects who believed they had adverse reactions to MSG and is the largest study to date. The results suggested, "large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe they react adversely to MSG. However, the frequency of the responses was low and the responses reported were neither consistent nor reproducible. The responses were not observed when MSG was given with food."
Is MSG listed on food labels?
Yes. FDA labeling regulations require MSG be declared in the ingredient statement on the label of any food to which it is added. It must be listed by its common or usual name, monosodium glutamate. It may not be declared as MSG. Monosodium glutamate is not labeled when it is a natural component of other foods such as cheese, tomatoes, or protein-based foods.
The Glutamate Association
P.O. Box 14266
Washington, DC 20044-4266
(202) 783-6135
www.msgfacts.com
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Monosodium Glutamate: A look at the Facts (Downloadable PDF)
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