Monosodium glutamate (MSG) is the sodium salt of glutamate, the most common naturally occurring amino acid. It is used as a food additive, and confers the protein-like flavor (amino acids are the building blocks of proteins) called umami to foods when used in the proper proportions.
Since the 1970s the use of MSG to flavor foods has been controversial. Many people report symptoms of what came to be known as “Chinese Restaurant Syndrome,” which can include headache, flushing, numbness, and weakness.
While MSG is typically blamed for these complaints, the high concentrations of salt, sugar, and gluten typical in American Chinese restaurants should also be suspect. Indeed, even after several double-blind placebo controlled studies, scientists have failed to establish any link between MSG consumption and the symptoms described.
It has also been suggested that MSG can lead to acute neurotoxicity. These fears arose from a study showing that neonatal mice that were injected with or force fed very high doses of MSG suffered from brain lesions. While this may sound alarming, the same toxicity did not occur when the MSG was administered with food, even at high doses.
That the toxicity does not occur in the presence of food should be reassuring, but evidence shows that the danger is even less significant for humans. Mice are particularly sensitive to MSG, and even much higher doses of orally ingested MSG are safe for human adults and babies.
Probably the biggest concern for ingesting substantial amounts of MSG is that it increases palatability (that’s the scientific term for tastiness) of foods and can encourage overeating. However this effect may actually be beneficial in patient groups who have trouble getting sufficient nutrition, such as cancer patients and the elderly.
To summarize, while foods that contain high doses of MSG are rarely healthy, MSG itself does not contribute to health problems.
When it comes to the science of wellness, distinguishing the facts from the urban legends can be tough. That’s why we’ve enlisted Darya Pino – a scientist, foodie, and self-proclaimed geek girl. Check out the ZocDoc Blog every Tuesday to see her bust the biggest myths in health.
Image: Best Dumplings in the World, a Creative Commons Attribution (2.0) image from Stewart’s photostream.