Monosodium glutamate
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Monosodium glutamate

October 13, 2019


Savory foods are inherently delicious—but
have you ever wondered why? In 1908, a Japanese professor pondered this
question when exploring what made kelp broth taste so good. He recognized a unique taste in it, that was
different from the four well-known tastes of sweet, sour, bitter, and salty. It turns out that glutamate, an amino acid
made by many plants and animals, was the source of this distinctive taste, which became known
as “umami” in reference to “umai”, the Japanese word for delicious. The professor isolated glutamate from seaweed
to produce a crystallized salt form of glutamate which combined one molecule of glutamate with
the ion sodium – to make it more tasty. This umami seasoning is still widely used
today, and is known as monosodium glutamate, or MSG. Glutamate is the most abundant amino acid
found in nature, and it’s one of the 20 amino acids that make up proteins in the human
body. Because glutamate is synthesized as part of
normal metabolism, it is considered a non-essential amino acid. In other words, we don’t technically need
to get it from food. Our bodies synthesize about 50 grams of glutamate
each day and store about 4.5 pounds of glutamate in major organs like the brain, muscles, kidneys,
and liver. On average we eat about 10 to 20 grams of
glutamate each day, mostly from protein-containing foods like meat, cheese, nuts, and legumes. Whether consumed from food or MSG, glutamate
is metabolized in the same way. In the saliva in the mouth, MSG separates
into its original two parts…glutamate and sodium…and then glutamate binds to its receptors
to elicit an umami, or savory, flavor sensation. In the stomach, there are more glutamate receptors,
and these activate the vagus nerve. The vagus nerve notifies the brain that protein-rich
foods have entered the stomach, and then the brain tells the stomach and intestines to
prepare for protein digestion. After leaving the stomach, glutamate enters
the small intestine where over 95% of the glutamate ingested is used as fuel by enterocytes,
the epithelial cells of the gastrointestinal tract. The rest is absorbed into the bloodstream
and delivered to cells to be used for metabolism or to make proteins. Now, it turns out that glutamate is also synthesized
by the brain, where it acts as a neurotransmitter. Some people have speculated that MSG may enter
the brain and even trigger migraine headaches. However, the glutamate we eat doesn’t affect
the amount of glutamate in our brain. This is because the glutamate we get from
food is almost entirely utilized during its journey through the gastrointestinal tract. The blood-brain barrier prevents the small
amount of glutamate in our bloodstream from entering the brain. Based on this aspect of human physiology and
confirmation in recent scientific reviews, the International Classification of Headache
Disorders removed MSG from its list of headache triggers in 2018. Within food, glutamate is either bound, or
in other words it’s attached to other amino acids in the form of a protein, or free by
itself. The more free glutamate there is, the more
umami flavor a food will have. Processes like aging or ripening will increase
the amount of free glutamate in a food. Take a deep red glossy tomato for example—it
will have more free glutamate than a firm pale one. Similarly, a cured ham will have more free
glutamate than fresh pork. Seasoning a food with MSG also increases free
glutamate. Some foods are very high in free glutamate. In 100 grams, Kombu seaweed has 2240mg, marmite
has 1960mg, and fish sauce has 1383mg. More common foods include parmesan cheese
which has 1680mg, soy sauce which has 1264mg, and oysters sauce which has 900mg. Some foods that may surprise you include walnuts
which have 658mg and tomatoes which have 246mg. Breast milk is also high in free glutamate
with its content varying by lactation stage and highest in mature milk. In fact, a breast-fed infants consume more
free glutamate per pound of body weight, than an adult. Overall, less than 10 percent of the glutamate
we consume is in the form of umami seasoning, or MSG. After decades of research, MSG is considered
safe by scientists and regulatory authorities around the world including United Nations
Food and Agriculture Organization, the World Health Organization, and the US Food and Drug
Administration. In fact, MSG has been recognized as a tool
to help people eat less salt, or sodium chloride. Consistently eating too much sodium can increase
blood pressure and may lead to hypertension, a top risk factor for cardiovascular disease. Which is why it’s recommended that we limit
sodium intake to less than 2,300 mg per day. But lower-sodium foods aren’t appealing
to everyone, which makes this recommendation a tough one to meet. MSG has the potential to help with this, something
noted in the 2019 Dietary Reference Intake report for sodium from the National Academies
of Science, Engineering and Medicine. Not only does MSG add flavor, but despite
having sodium in its name, MSG contains three times less sodium by weight than table salt. For example, increasing glutamate content
of foods while decreasing salt in a recipe can reduce the overall sodium content by up
to 40%. Okay – as a quick recap. Glutamate is the amino acid responsible for
the flavor of umami and plays an important role in digestion by signaling for protein
digestion and fueling the cells of the GI tract. Our bodies make glutamate and it’s also
present in a variety of whole foods. Glutamate can also be added by seasoning foods
with MSG. In the saliva in the mouth, MSG separates
into glutamate and sodium, which is why the body doesn’t differentiate between the glutamate
in umami seasoning and the glutamate in every day foods. Extensive research has shown that MSG is safe
to consume, doesn’t cause headaches and could be a helpful tool for lowering the amount
of sodium people eat.

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  1. Hi dear Osmosis, I am a medical student and this channel is the best medical channel to, may you upload physiology and biochemistry videos!
    thanks

  2. Come on, get off that low salt diet train, it's a myth that causes more problems than it solves (if any at all), you should know better!

  3. 1'50", probably same from food or MSG cristals. Indeed, I quite dairy products 17 years ago (cheese is addictive), but I remember clearly that i used to be very SLEEPY after eating cheese.
    2'40" Some people have speculated etc. Speculated? I have FAINTED several times … even not knowing there was glutamate in the food (I live in China, and the last time was in an Indian restaurant in Shanghai, so don't say to me it was psychologic, i did not expect MSG in Indian food).
    3'16" MSG has been removed from the list of foods that can cause headaches… by "regulatory authorities": They also said that glyphosate was not harmful, they allowed Thalidomide to get to the market, Vioxx and so on and so on. And you trust the FDA, the FAO, the USDA? The guys who have responsibility there have double job: one at Monsanto one at the FDA> they are the last ones i would ever consider as serious!
    5'23": it would replace sodium? REALLY. Every time I had MSG, i had to drink like mad before fainting or losing eye sight! I can drink ONE litre of water non-stop after a dish flavoured with MSG. NOT with table salt!

    As a summary, I'd say that AJINOMOTO is a HUGE company, and that they have interfered with your "regulatory authorities".
    I will NOT use MSG, and will continue to consume SALT.

  4. Absolute garbage what RRC have been done. Thalidomide and talcum power were in the same category as this video. Bad bad bad video osmosis

  5. The Ajinomoto Group (food corporation) would be proud of your over simplification regarding the assurances of safety. However, I recommend everyone looks deeper into the existing research of excitotoxins, like MSG and Aspartame, and the real damage they can do. A great book written by a very experienced Neurosurgeon, Russel Blaylock, called "Excitotoxins", dives much deeper into the research and shows very clearly how free glutamate can bypass the BBB (which does not protect the entire brain) and cause severe damage to the brain causing several Neurodegenerative diseases. It is very well referenced and for those that want to understand this topic better you should pick up a copy, along with his other book "Health and Nutrition Secrets that can Save Your Life." Just a suggestion. That all being said, I love Osmosis and have found great value and education from your content.

  6. Still somehow people wanna eat far more of the stuff that contains MSG than that with just salt. And producers don't even lower the salt content, they simply add the MSG to the oversalted product to make consumers devour even more. What else would they do? It's capitalism.

  7. I was curious and got me some of that MSG stuff by Ajinomoto. No matter how much I put some of that stuff on my food though, I simply can't detect any difference, except that everything tastes a bit more salty when I use a lot of it.

     I call hoax.

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