Monosodium Glutamate (MSG) is a flavor enhancer that, though originally derived through a “natural process,” can cause severe reactions in some people. Many scientists and researchers believe MSG is highly toxic and evidence exists that it may have long term effects even on those individuals who do not exhibit immediate symptoms. Some of the loudest critics of MSG, however, have also been accused of inflating the hype surrounding the common additive’s potential risk. As with most controversial and polarizing issues, the truth lies somewhere between the extremes.
Because of the controversy surrounding this additive, many food manufacturers do not want the ingredient on the label of processed foods they package. These manufacturers are able to disguise the presence of MSG in their products through careful reformulation of their ingredients. This can lead to the formation of MSG as a byproduct of free glutamate amino acids joining with free sodium to form the MSG while it is being consumed. Hydrolyzed Proteins are proteins which have been chemically separated into their amino acid building blocks, including glutamic acid, allowing for the formation of free glutamate.
Labeling for MSG is only required when the substance is added as a direct ingredient, so ingredients added specifically to form MSG need not be labeled as such. Hydrolyzed Proteins or Hydrolyzed Vegetable Proteins are often found along with Disodium Guanylate, itself a flavor enhancer already suspected of being unsafe for asthmatics, people with gout and infants. The Disodium Guanylate is able to provide the sodium necessary for the free glutamate in Hydrolyzed Protein to form Monosodium Glutamate.
Why Is MSG Toxic?
Monosodium Glutamate is considered both an excitotoxin and a neurotoxin. Excitoxins destroy cells in the brain by causing them to fire repeatedly until the cells are worn out. Studies in the 1960s linked MSG fed to infant mice to the destruction of neurons in their brains. These studies generated enough public pressure on baby-food companies that most stopped adding MSG to their products. Today, MSG and the artificial sweetener, aspartame, are probably the most common of the excitotoxins found in processed food.
Studies on people have shown reactions ranging from nausea and headache to weakness and burning sensations. More extreme reactions include increased heart rate and difficulty breathing.
MSG acts like a neurotropic drug, directly affecting the nervous system. It has the potential to affect insulin metabolism, resulting in both excessive insulin secretion and insulin resistance. MSG has been associated with anxiety attacks, Attention Deficit Syndrome, depression, hyperactivity, infertility, mood swings, seizures, tremors and more. Some symptoms of what is referred to as “free glutamate toxicity” are a mere inconvenience (drowsiness or dizziness) while others are considerably more serious. Most symptoms pass relatively quickly, possibly even unnoticed, though there is a growing belief that effects may be cumulative and that sometimes effects may also be delayed.
Pregnant women have an increased risk of their fetus developing smaller pituitary, thyroid, ovary, or testes that can result in reproductive dysfunction when they consume MSG. Associations have also been established that MSG may create chemical sensitivities within some people, especially with regard to other excitotoxins such as aspartame ( found in NutraSweet).
Origins of Monosodium Glutamate
People in parts of Asia originally used a seaweed broth to obtain the flavor-enhancing effects of MSG, but today MSG is made by a fermenting process using starch, sugar beets, sugar cane, or molasses. In Japan, MSG is known as Aji-no-moto and was given its own adjective to describe the extra flavor: Umami, or the fifth taste. In Hemispheres Magazine’s June, 2010 article, “Flavor of the Month,” author Adam Baer describes how he discovered umami after temporarily losing his sense of taste as the result of endonasal surgery. Baer writes, “Last year, food scientists at Philadelphia’s Monell Chemical Senses Center announced new research showing that humans are hardwired to detect this fifth taste and probably to crave it. Indeed, many of the world’s cuisines highlight foods rich in umami-truffles, soy sauce, tomatoes and aged cheese, for example-all of which just happen to show high levels of a naturally occurring chemical, glutamic acid.”
Many foods, such as Parmesan cheese and tomatoes, contain glutamate that occurs naturally. Still, no reactions have been reported to such foods. It is only with the processed foods that there have been established links between MSG or free glutamates and the various symptoms.
Are Risks of MSG Overstated or Based on Pseudo-Science?
In the April 5, 2006 newsletter from Sixwise.com, “12 Dangerous Food Additives: The Dirty Dozen Food Additives You Really Need To Be Aware Of,” neurosurgeon Dr. Russell Blaylock links excitotoxins like MSG and aspartame to sudden cardiac death. Especially in athletes, where heart rates will be notably higher during workouts or performance, Dr. Blaylock asserts the connection between long-term excitotoxin damage to the muscles of the heart and heart attacks. Dr. Blaylock defines excitotoxins as “a group of excitatory amino acids that can cause sensitive neurons to die.”
While Dr. Blaylock’s book Excitotoxins: The Taste That Kills (Health Press, 1994) is often quoted as a reliable source and he vigorously defends its science online, it should be noted as a matter of disclosure that QuackWatch.com does list him on their “Promoters of Questionable Methods” page (accessed September 28, 2010), though without any footnotes as to why he is included in the list (his Blaylock Wellness Report email newsletter is also listed on their page for “Non-Recommended Periodicals,” presumably due to its often over-the-top approach). Robert T. Carrol’s Skeptic’s Dictionary also has an entry on Dr. Blaylock (accessed September 28, 2010) which paints him as a conspiracy theorist and supplement huckster in the same vein as Joseph Mercola of Mercola.com (another web site with a medical newsletter that reports on the health threats of MSG). Media Matters for America at MediaMatters.org also holds Dr. Blaylock to task for fearmongering on behalf of the Right-Wing Newsmax email newsletter in the September 27, 2010 MediaMatters.org report, “Newsmax enlists serial misleader McCaughey to scaremonger about health care (and, of course, sell you something)” (accessed September 28, 2010).
Extreme Opinions on MSG
What is clear is that there are extremes at play with regard to opinion on the safety of MSG. On one side, particularly with regard to Asian cuisine, MSG is seen as indispensable with regard to flavor enhancement and mainstream science continues to consider it “safe” even though many people may be sensitive to it much the same way many people are allergic to any number of food ingredients. On the opposing side, there are alarmists who portray the processed food industry as deliberately poisoning the population in the name of profit. Most certainly the truth lies somewhere in the middle, with well-intentioned people on both sides of the argument.
Many consumers have experienced the ill effects of MSG, which leave them with a headache, increased heart rate, nausea or vomiting after eating MSG-containing foods. For these individuals, it makes sense to search out the many ways in which MSG may be disguised in the foods they purchase. And for those who are not consciously aware of any symptoms they may or may not be experiencing, attempting to provide themselves with a healthier or cleaner diet may still provide long term benefits.
The Food Democracy site, in it’s October 16, 2007 posting “Food Additives Demystified,” fooddemocracy.wordpress.com/2007/10/16/food-additives-demystified/ healthy-eating-politics.com/food-additive.html hemispheresmagazine.com/2010/06/01/flavor-of-the-month/
The very useful Truth in Labeling web site’s “Hidden Sources” page lists many ingredients associated with MSG: truthinlabeling.com/Jack_hiddensources.htm
The Food and Drug Administration web site’s report on “Food Ingredients and Colors,” revised April 2010, discusses how under the Food Additives Amendment, two groups of ingredients were exempted from the regulation process: fda.gov/food/foodingredientspackaging/ucm094211.htm
GROUP I – Prior-sanctioned substances – are substances that FDA or USDA had determined safe for use in food prior to the 1958 amendment. Examples are sodium nitrite and potassium nitrite used to preserve luncheon meats.
GROUP II – GRAS (generally recognized as safe) ingredients – are those that are generally recognized by experts as safe, based on their extensive history of use in food before 1958 or based on published scientific evidence. Among the several hundred GRAS substances are salt, sugar, spices, vitamins and monosodium glutamate (MSG). Manufacturers may also request that FDA review the industry’s determination of GRAS Status. sixwise.com/newsletters/06/04/05/12-dangerous-food-additives-the-dirty-dozen-food-additives-you-really-need-to-be-aware-of.htm quackwatch.com/11Ind/index.html skepdic.com/blaylock.html mediamatters.org/blog/201009270043