Monosodium glutamate
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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.
Key Takeaways
Monosodium glutamate (MSG) is a type of sodium salt that is commonly used as a food additive and flavor enhancer. It is made from the amino acid glutamic acid, and is used to enhance the flavor of many processed foods. MSG is also known to have potential health benefits, such as aiding in digestion.
Our bodies make glutamate, but it's also present in a variety of whole 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.