Practical Wellness
About two decades ago, while reading a menu at a Chinese restaurant, my father noticed a footnote saying ‘No MSG.’ Curious to see if the waiter could explain what MSG was, my dad asked him.
‘Monosodium gourmet,’ came the reply.
A sample of people today might know that MSG stands for monosodium glutamate, but most couldn’t say where it comes from or why it’s added to so many foods; after all, MSG is just one of hundreds of ingredients found on food labels these days.
A small percentage of people, though, need to avoid MSG because it gives them headaches, heart palpitations, and a host of other unpleasant symptoms. But does that mean MSG is potentially harmful to everyone, even those who don’t suffer any immediate ill effects? Some people say yes; others, including many of the government agencies that regulate our food, contend that MSG is entirely safe.
Where does MSG come from?
For centuries, the Japanese have used seaweed to improve the taste of food. In 1908, chemistry professor Kikunae Ikeda isolated the substance in seaweed responsible for the flavor enhancement, an amino acid called glutamic acid, or glutamate. Ikeda proposed that glutamate stimulated a new taste, which he named ‘umami’ after the Japanese word umai, meaning delicious. Distinctly different from the four familiar tastes (sweet, sour, salty, and bitter), umami is best described as savory, and is found in protein-rich foods like cheese, meat, and fish.
Glutamate is one of 20 amino acids that our bodies use to make proteins. When bound into a protein molecule, glutamate does not have flavor-enhancing properties, but when freed through a chemical reaction, ‘free glutamate’ elicits the umami taste. Originally isolated from wheat gluten, glutamate is now produced commercially by fermentation of bacteria, then neutralized with sodium hydroxide to form monosodium glutamate, or MSG.
It wasn’t until 2000 that researchers at the University of Miami confirmed that animals and humans have receptors for the umami taste. But the food industry didn’t need researchers to tell them what they’d known for years: MSG is a powerful flavor-enhancer, which is why, for decades, they’ve been adding it to soups, stews, sauces, processed meats, dips, dressings, chili, marinades, seasoning salts, and a variety of snack foods. You can even buy crystalline MSG, under the product name Accent.
Is MSG safe?
You might never have heard about MSG any more than you would, say, the additive xanthan gum, were it not for a cluster of symptoms that sprang up around the ’60s dubbed Chinese Restaurant Syndrome (CRS), so named because people exhibited adverse effects after eating Chinese food. Renamed MSG Syndrome Complex, symptoms include headaches, sweating, flushing, heart palpitations, nausea, weakness, chest pain, worsening of asthma, and a numbing, tingling, or tightness in the face, neck, and arms.
The Mayo Clinic reports that, ‘researchers have found no definitive evidence of a link between MSG and these symptoms,’ but that, ‘researchers acknowledge that a small percentage of people may have short-term reactions to MSG.’ The Mayo Clinic does not explain how people can react to MSG without there being a link between MSG and their reactions.
The FDA classifies monosodium glutamate as Generally Regarded As Safe (GRAS), though they require that MSG be listed on the ingredients label. The problem, say some food activists, is twofold. First, despite numerous labeling infractions reported to the FDA over the years, enforcement is weak. Second, many foods contain hydrolyzed vegetable protein, autolyzed yeast, and dozens of other ingredients that contain or can release free glutamate, which, in turn, readily forms MSG in the presence of sodium ions, ubiquitous in foods and body fluids.
For anyone particularly sensitive to MSG, a food ingredient or additive that can rapidly release free glutamate can cause MSG Syndrome Complex. The government recognizes this, and has created labeling laws to inform the consumer — but only partially. The consumer still needs to know what to look for.
Labeling laws
If manufacturers add MSG to a food, then the words ‘monosodium glutamate’ must appear in the ingredients list. If manufacturers add ingredients like hydrolyzed protein that contain or can release free glutamate, then the product label cannot state ‘No MSG’ or ‘No MSG Added,’ but neither does it have to state that its ingredients can easily form MSG. So concerned consumers are left searching the label for any and all potential sources of free glutamate. This is no small task; dozens of ingredients contain some portion of free glutamates, including hydrolyzed vegetable protein, autolyzed yeast, gelatin, soy sauce, soy protein, stock, and milk solids (for a full list, see sidebar). Even citric acid, often added to beverages, can contain glutamate due to the way it’s processed.
The words ‘all natural,’ ‘organic,’ ‘healthy,’ ‘low-fat,’ ‘lite,’ and ‘low-sodium’ do not guarantee that a product is free of MSG or glutamates. In fact, low- and non-fat foods usually contain more glutamates to compensate for flavors that are lost when fats are removed from a product.
Research
Despite plenty of anecdotal evidence that some people react adversely to added MSG, research has not been able to prove definitively that MSG causes these reactions. In reading many of these studies, I discovered the following:
1. Some studies looked for a specific triad of symptoms (palpitations, weakness, and numbing in the neck and arms) first identified as CRS. If participants ingested MSG and experienced symptoms different from the ‘triad,’ researchers concluded, inexplicably, that MSG did not cause CRS. Such a conclusion is puzzling, considering that CRS was aptly renamed MSG Syndrome Complex, which includes a much broader array of symptoms.
2. Different studies reached different conclusions, linking symptoms with irritation of the esophagus, vitamin B6 deficiency (supplementing prevented CRS), high sodium intake, or a histamine reaction (some Chinese meals approach the FDA toxic threshold for histamine in foods).
3. Many studies were poorly designed or were biased in selection of participants.
4. In one of the larger, better-designed studies, participants were put through a number of protocols, or MSG ‘challenges,’ and could only advance to the next one if they reacted to MSG and not a placebo (i.e. it wasn’t ‘just in their heads’). Even for subjects who advanced to the final protocol, the outcomes were not always consistent or reproducible, leading researchers to conclude there was ‘no definitive link.’
5. In 1957 and 1969, researchers found that in baby mice, MSG de-stroyed retinal cells and caused brain lesions, obesity, and other disturbances. When researchers took this information to the food industry, manufacturers stopped adding MSG to baby food, but for 10 years continued to add glutamate sources at levels that, in the mice studies, destroyed brain cells.
This harmful effect of glutamate on brain cells is known in the field of neurology as excitotoxicity. Glutamate is the most common neurotransmitter (chemical messenger) in the brain of mammals, and it operates in a series of complex checks and balances.
But excess levels of glutamate can disrupt this balance, triggering (or exciting) the cell to keep firing off nerve impulses. This causes the cell to damage and destroy its DNA, mitochondria (energy producers), and eventually the cell itself.
Though the blood-brain barrier keeps most surplus glutamate from reaching neural cells, there are places in the brain where glutamate can pass through, plus a number of conditions in which the barrier is compromised: stroke, diabetes, severe hypoglycemia, head injury, degenerative diseases (Alzheimer’s, ALS, and Parkinson’s), alcoholism, and alcohol withdrawal. In addition, some doctors believe that fetuses and young children, whose neural pathways are forming, are especially susceptible to excitotoxins and the effects of MSG.
Avoiding MSG
If you want to avoid MSG, you have to become a die-hard label reader and avoid the sources of glutamate listed in the sidebar. But you’ll automatically remove MSG and glutamates from your diet if you steer clear of processed foods and choose instead foods that are close to their origins, such as veggies, fruit, legumes, and whole grains.
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