What is MSG, and is it actually bad for you? - Sarah E. Tracy
In 1968, Dr. Robert Ho Man Kwok felt ill
after dinner at a Chinese restaurant.
He wrote a letter detailing his symptoms
to a prestigious medical journal,
pondering whether his illness had resulted
from eating monosodium glutamate—
also known as MSG.
Kwok’s connection between his headache
and this common seasoning
in American Chinese cuisine
was just a hunch.
But his letter would dramatically change
the world's relationship with MSG,
inspiring international panic,
biased science,
and sensationalist journalism
for the next 40 years.
So what is this mysterious seasoning?
Where does it come from,
and is it actually bad for you?
MSG is a mixture of two common substances.
Sodium, which is well-established
as an essential part of our diet,
and glutamate, a very common amino acid
found in numerous plant and animal
proteins.
Glutamate plays a key role
in our digestion, muscle function,
and immune system.
Around the time of Dr. Kwok's letter,
it had been identified as an important
part of our brain chemistry.
Our body produces enough glutamate
for all these processes,
but the molecule is also present
in our diet.
You can taste its signature savory flavor
in foods
like mushrooms, cheese, tomatoes,
and broth.
Chasing this rich flavor
is what led to MSG’s invention in 1908.
A Japanese chemist
named Dr. Ikeda Kikunae
was trying to isolate the molecule
responsible for a unique flavor
he called “umami,”
meaning “a pleasant, savory taste.”
Today, umami is recognized as one
of the five basic tastes in food science.
Each basic taste is produced by unique
molecular mechanisms
that can’t be replicated by combining
other known tastes.
In the case of umami,
those mechanisms arise
when we cook or ferment certain foods,
breaking down their proteins
and releasing amino acids like glutamate.
But Ikeda found a savory shortcut
to producing this chemical reaction.
By isolating high quantities of glutamate
from a bowl of noodle broth
and combining them with another
flavor enhancer like sodium,
he created a seasoning that instantly
increased the umami of any dish.
The result was a major success.
By the 1930s, MSG was a kitchen staple
across most of Asia;
and by the mid-20th century,
it could be found in commercial food
production worldwide.
So when Dr. Kwok's letter was published,
the outrage was immediate.
Researchers and citizens demanded
a scientific enquiry
into the popular additive.
On one hand,
this wasn’t unreasonable.
The substance hadn't been
tested for toxicity,
and its health impacts
were largely unknown.
However, it’s likely many people
weren’t responding
to a lack of food safety regulation,
but rather the letter’s title:
“Chinese Restaurant Syndrome.”
While MSG was commonly used
in numerous cuisines,
many Americans had longstanding prejudices
against Asian eating customs,
labeling them as exotic or dangerous.
These stigmas fueled racially
biased journalism,
and spread fear that eating at Chinese
restaurants could make you sick.
This prejudiced reporting extended
to numerous studies about MSG and umami,
the results of which were much less
conclusive than the headlines suggested.
For example, when a 1969 study found
that injecting mice with MSG
caused severe damage
to their retina and brain,
some news outlets jumped to proclaim
that eating MSG could cause brain damage.
Similarly, while some studies reported
that excess glutamate
could lead to problems like Alzheimer’s,
these conditions were later found to be
caused by internal glutamate imbalances,
unrelated to the MSG we eat.
These headlines weren't just a product
of prejudiced reporters.
Throughout the late 60s and early 70s,
many doctors also considered
“Chinese Restaurant Syndrome”
to be a legitimate ailment.
Fortunately, today’s MSG researchers
no longer see the additive
in this discriminatory way.
Recent studies have established the vital
role glutamate plays in our metabolism,
and some researchers even think MSG
is a healthier alternative
to added fat and sodium.
Others are investigating whether
regular consumption of MSG
could be linked to obesity,
and it is possible that binging
MSG produces headaches,
chest pains, or heart palpitations
for some people.
But for most diners, a moderate amount
of this savory seasoning
seems like a safe way
to make life a little tastier.
