Take Some Time to Understand MSG

Monosodium glutamate (MSG) is an additive in many foods we eat. STACK Expert Kait Fortunato explains what it is and how it can affect you.

Food with MSG

Food appeals to our senses because of the enticing flavor we taste with each bite. As individuals, we all have different food preferences, and flavor is what separates one from another.

Monosodium glutamate (MSG), a form of the naturally occurring chemical glutamate, was conceived as an ingredient to enhance flavor. It is created through a fermentation of starch, sugar beets, sugar cane or molasses. Although it's tasteless on its own, MSG enhances the taste of other foods, bringing out the pleasant, savory flavor known as "umami." MSG is basically the sodium salt of glutamate. The human body treats glutamate the same whether in its natural state or in the form of MSG.

MSG Is Recognized as Safe by the FDA

MSG is one of the most extensively researched substances in the food supply, and many government agencies support it as being safe to eat. The International Food Information Council Foundation provides a timeline of approvals for MSG:

  • 1958: U.S. Food and Drug Administration designates MSG "generally recognized as safe" (GRAS).
  • 1979: National Academy of Sciences confirms safety of MSG as a food ingredient.
  • 1988: Joint Expert Committee on Food Additives in the UN World Health and Food and Agricultural Organizations places MSG in the safest category for food additives.
  • 1995: FDA reaffirms MSG safety based upon a report from the Federation of American Societies for Experimental Biology.

MSG May Cause Adverse Reactions

Despite being "generally recognized as safe" by the FDA, MSG must be listed on food labels because of reports from people who have experienced adverse reactions. These include headaches, flushing, sweating, numbness, chest pain, rapid heart beat, nausea and weakness. No research definitively connects MSG to these symptoms, but in rare cases they may be linked.

Repeated research has linked MSG to asthma, provoking cases in humans, as seen in this study,which tested 32 subjects after consuming MSG.

Conventional toxicity studies in which mice were administered dietary MSG revealed no specific carcinogenic effects, but parenteral administration did show lesion production on the central nervous systems. This occurred less in tests on primates.

There are conflicting arguments and limited proven cases, but glutamate, a non-essential amino acid, is a nerve impulse transmitter in our bodies. Therefore, some speculate that MSG reactions result from over-stimulation of these receptors.

MSG May Cause Weight Gain

Some argue that MSG can be linked to weight gain, because of its heavy concentration of sodium. However, MSG contains only one-third of the amount of sodium as table salt and is used in much smaller amounts.

No studies have tested MSG in relation to obesity in humans, but treatment of mice with repeated doses of MSG produced obesity and endocrinological dysfunction, believed attributable to lesions on the hypothalamus, the gland responsible for homeostasis, including weight regulation, in the body. MSG may also be linked to enhanced insulin sensitivity and therefore greater uptake of glucose into adipose tissue.

MSG Doesn't Have to Be Labeled

If used as an additive, MSG must be listed on the ingredients label. The trouble is, natural forms of MSG are not required to be listed. Many ingredients contain MSG naturally, including hydrolyzed vegetable protein, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts and protein isolate, as well as tomatoes and cheeses.

MSG Can Be Avoided

According to this New York Times article, many restaurants use MSG without saying so, and sometimes without realizing it.

If you have a reaction to MSG, at least pay attention to what you're buying in the grocery store. As much as possible, limit packaged foods, canned goods and pre-made sauces and dressings, since most brand name soups, flavored chips, and mayonnaise contain MSG. Make your own dressings and broths to have on hand for family meals. Eat whole, locally grown foods.

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