MSG (Monosodium Glutamate) is added to foods as a taste enhancer. The FDA says MSG is safe, except for some folk to take too much of it, or those who suffer from asthma.
At MSGTruth.Org, there is a long research list that begs to differ. There's also NoMSG.com, a consumer group site battling against MSG; MSGMyth.com, a reference website compiled by Debbie Anglesey; MigraneWeb.com, which has a section of its site dedicated to MSG; and the British watchdog group's FedUpWithFoodAdditives.Info's fact sheet on MSG.
Yes, it's controversial. A nice, concise summary of that controversy is found on the British fact sheet.
For those who have had a reaction to MSG, there's no debate. Also called "Chinese Restaurant Syndrome," reactions to MSG can range from feelings of nausea to migranes, dizziness, and heart palpitations. It can trigger asthmatic attacks. And, it's not a quick response/recovery: it takes a good couple of days to bounce back from an MSG reaction according to the University of Illinois Medical Center.
There are those that argue that long term effects of MSG can include Parkinson's Disease, Alzheimer's Disease, Autism in children, Diabetes (I and II), and obesity in children and adults. (Yes, MSG is argued to cause you to want to eat more.)
Both sides can agree on one thing: too much MSG will cause bad reactions in humans. The FDA report suggests that amount to be around 3 grams. And, with the growing list of foods containing MSG, perhaps it's not too hard to imagine that more and more people are getting excess MSG in their diets ....
From MSGTruth.Org, a partial list of common foods with MSG (go to link for complete list):
McDonald's French Fries
KFC® fried chicken and most of their other products
Progresso® Soups - all of them
Kraft® products nearly all contain some free glutamate
Planters® salted nuts - most of them
Accent® -this is nearly pure MSG
Braggs® Liquid Aminos - sold at Whole Foods
processed cheese spread
supermarket poultry or turkeys that are injected or "self-basting"
flavored Ramen noodles
boullion - any kind
flavored potato chips
Parmesan cheese - naturally high in free glutamate
From Rense.com, a partial list of ingredients that all mean the same thing, MSG has been added, quoting from Excitotoxins - The Taste That Kills by Russell Blaylock, MD:
Hydrolyzed Vegetable Protein
Hydrolyzed Plant Protein
Plant Protein Extract
Textured Protein (Including TVP)
Hydrolyzed Oat Flour
And, if that's not enough, there's also the ingredient "natural flavor" or "natural flavoring." Yep, you guessed it: another synonym for MSG.
Personally, I believe MSG is bad for me and I avoid it. I know enough to know that Panda Express Gourmet Chinese Food takeout causes me to feel terrible the next day -- but my real testimonial comes from some flavored Kettle Chips (Maui Onion) that I splurged on, even though I usually avoid fried potato chips. Bad reaction (including dizziness, which was scary), and the cause? MSG.