The MSG Myth: Are There Really Side Effects?

By: Brierley Wright, M.S., R.D.  |  Friday, September 12, 2014
MSG—or monosodium glutamate—is a flavor enhancer used in savory foods, especially Asian foods. It contains sodium, but only a third of the amount that you’d get from the same amount of salt.
MSG also includes glutamic acid (aka glutamate), an amino acid that’s found naturally in foods like tomatoes, mushrooms and soybeans and is the source of our fifth taste—umami.
In fact, we eat about 13 grams of natural glutamate a day on average, compared to only around half a gram from MSG.
Some people say they have an MSG allergy—or that MSG gives them headaches, worsens their asthma, causes chest pain or palpitations, or causes mild mood changes or other symptoms, all of which are collectively referred to as Chinese Restaurant Syndrome (because MSG is commonly found in Asian-style meals).
Contrary to popular belief, decades of research fails to support the link between MSG and these reported side effects.
Modest amount of MSG found in the typical Western diet is not linked to symptoms of Chinese Restaurant Syndrome, according to scientific literature from the 1970s to today.
No adverse symptoms were observed when people consumed MSG as part of a meal—even at high doses (up to 147 grams/day), according to a review of studies, published in 2000 in the Journal of Nutrition.
There’s one caveat though: eating MSG may lead to classic symptoms of Chinese Restaurant Syndrome when it is consumed solo and on an empty stomach.
In a 2013 study, researchers gave healthy adults about 10 grams of MSG on average (a fairly large dose) without any food.
Almost all of them experienced headaches, as well as short-term increases in blood pressure and heart rate.
But because MSG is generally used in small amounts as a flavoring (like salt), the likelihood that you’d eat it by itself is slim.
MSG might just be the most love-to-be-hated additive of the day, but the science fails to supports its “bad guy” reputation.