Monosodium Glutamate (MSG)


Tomatoes contain glutamateAs people are becoming more conscious about the food they eat, they are also becoming more suspicious about certain additives that may be in that food. One of the additives that has fallen out of favor is monosodium glutamate, better known as MSG. Once associated with Chinese restaurants, the commercial flavor enhancer is more commonly used in processed foods, including canned vegetables and soups, sauces, dressings, and broths, to name just a few. There is a great deal of confusion when it comes to MSG, so let’s start with the basics.

 

In 1907, Tokyo Imperial University chemistry professor and researcher Kikunae Ikeda was curious about what gave kombu broth its flavor—kombu is a kind of seaweed that Japanese cooks traditionally used to enhance the flavor of food. Ikeda evaporated a large amount of kombu broth and identified the brown crystals left behind as glutamic acid, a common amino acid. Ikeda stabilized the glutamic acid with sodium and soon patented a method of mass-producing the crystalline salt of glutamic acid—monosodium glutamate.[i]MSG is essentially a combination of glutamic acid, salt, and water. Today it is typically produced by fermentation of starch, sugar beets, sugar cane, or molasses.[ii]

 

What is glutamate?

The ions and salts of glutamic acid are known as glutamates (MSG is one kind of glutamate), and Ikeda found that it was the glutamate in the seaweed that made food taste better. The chemist suggested that glutamate stimulated a taste that was distinct from the four known tastes of sour, sweet, salty, and bitter. He called this fifth taste “umami,” which loosely translates to “savory” in English.[iii]Since Ikeda’s discovery, scientists have learned that glutamate is a neurotransmitter that stimulates specific receptors in the taste buds that induce a savory taste.

 

Glutamate is a natural component of many foods including soy sauce, Parmesan cheese, peas, tomatoes, mushrooms, milk, eggs, some meats, and yeast, and is what gives these foods their savory taste. Interestingly, human breast milk also contains rather large amounts of glutamate—babies have very basic taste buds and the glutamate is believed to encourage them to drink their mother’s milk.[iv][v]The human body treats glutamate that is added to foods in the form of MSG the same as the glutamate found naturally in food,[vi]and in fact, it is the glutamate that people are sensitive to, not just the MSG.

 

Food

Naturally-Occurring Free Glutamate per 100 mg of Food

Parmesan cheese

1200mg/100g

Soy sauce

926mg/100g

Peas

200mg/100g

Tomatoes

140mg/100g

Duck

69mg/100g

Chicken

44mg/100g

Beef

33mg/100g

Eggs

23mg/100g

Human milk

22mg/100g

     Source: “Monosodium Glutamate: A Safety Assessment” Food Standards Australia New Zealand, 2003

 

What about hydrolyzed proteins?

Hydrolyzed proteins are acid or enzyme-treated proteins from certain foods like soy meal, wheat gluten, corn gluten, or yeast. When these proteins are hydrolyzed, the amino acids, including glutamate, are released. Hydrolyzed protein contains anywhere from five to 20 percent glutamate. Hydrolyzed protein is used in the same manner as MSG in many processed foods.[vii]

 

Regardless of dietary source (protein, protein hydrolysates, or salts of free glutamic acid, including MSG), all glutamate molecules entering the body through the gastrointestinal tract are structurally identical,[viii]so if you are an individual who is sensitive to glutamates, you will want to avoid all of these.

 

Glutamate sensitivity

Though it is not a food allergy, a small percentage of the population is sensitive to glutamates and may experience short-term symptoms when they ingest glutamates, including headache, flushing, sweating, tingling or burning in and around the mouth, shortness of breath, and/or nausea.[ix]Additionally, for some asthmatics, glutamates can make asthma symptoms worse. Glutamates open calcium channels in the body, affecting blood vessel vasoconstriction, thus possibly leading to headaches and asthma attacks in some people.

 

While a food product may not contain added MSG, it may contain other glutamates (remember, glutamates naturally occur in many foods). If you suspect you are one of the small number of people who are hypersensitive to glutamates, look for these ingredients on labels, as they all contain glutamate: any type of hydrolyzed protein, autolyzed yeast protein, yeast extract, yeast nutrient, and natural flavor or flavoring. Additionally, you should avoid whey protein concentrate and liquid aminos, as they also naturally contain glutamates. 

 

References



[i]www.wikipedia.org/wiki/Glutamic_acid(flavor)

[ii]www.wikipedia.org/wiki/Glutamic_acid(flavor)

[iii]http://pubs.acs.org/cen/whatstuff/stuff/8130sci3.html

[iv]“Sodium Glutamate: A Safety Assessment,” Food Standards Australia, New Zealand. June 2003

[v]International Food Information Council Foundation, “Everything You Need to Know About Glutamate and Monosodium Glutamate.” Jan. 1997; www.ific.org/publications/brochures/msgbroch.cfm

[vi]International Food Information Council Foundation, “Everything You Need to Know About Glutamate and Monosodium Glutamate.” Jan. 1997; www.ific.org/publications/brochures/msgbroch.cfm

[vii]www.wikipedia.org/wiki/Glutamic_acid(flavor)

[viii]Geha Raif S, et al. “Review of Alleged Reaction to Monosodium Glutamate and Outcome of a Mulitcenter Double-Blind Placebo-Controlled Study,” Journal of Nutrition. 2000; 130:1058S-1062S; www.jn.nutrition.org/cgi/content/full/130/4/158S



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03/29/2012 - 2:42pm



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