The human tongue picks up five basic tastes: sweet, sour, salty, bitter, and umami.
That last flavor—umami—comes from two Japanese words that together mean “delicious taste.” Kikunae Ikeda, a professor at the Tokyo Imperial University, was the first to describe and identify umami in 1908.
Umami is distinctly different from sweet, sour, salty, and bitter. It makes the mouth salivate and leaves an aftertaste that many find pleasant but difficult to describe. You can find umami in tomatoes, parmesan cheese, shiitake mushrooms, bonito flakes, soy sauce, cured meats, and the seaweed kombu.
Professor Ikeda found that the amino acid glutamate is largely responsible for umami. He submitted a patent for glutamate salt, or monosodium glutamate (MSG), and began producing it in 1909. (1)
What Is Umami?
Natural glutamate gives food its umami flavor. (2) The following foods are high in glutamate and have that distinct umami flair when paired with other umami-rich foods:
Synthetic MSG is harmful to your health. MSG may be found in processed foods and has been linked to inflammation, type 2 diabetes, infertility, and much more.
- Ocean vegetables, especially kombu seaweed
- Green tea
- Tomato, especially ripe tomato
- Chinese cabbage
- Cheese, such as parmesan or Roquefort
Interestingly, umami is one of the first flavors that a newborn infant encounters.
Research has found that glutamate is the most abundant amino acid in breast milk, making up more than 50% of the amino acids in breast milk. (3)(4) The naturally high concentrations of glutamate (umami) in breast milk support newborn gut tissue. Glutamate is an energy source for cells that make up the lining of the gut. (5)
In adults, umami is equally important. Studies show that glutamate drives our digestion, sending signals to the stomach, small intestine, and liver. (6) In fact, just like the tongue, cells in the stomach can also sense umami. (7)
Besides its role in digestive health, glutamate is also an excitatory brain chemical. It plays an essential role in learning and memory. The body uses glutamate to produce another brain chemical called GABA (gamma-aminobutyric acid), which is a calming and inhibitory brain chemical in the adult brain.
Sometimes the body loses the ability to convert glutamate into GABA. A build-up of glutamate with a deficiency of GABA has been linked to serious disorders, like:
- Alzheimer’s disease
- Stiff man syndrome
Glutamate’s role in brain development and brain health points to why MSG (synthetic glutamate salt) has such a bad reputation.
The Problem with MSG
MSG is a synthetic reproduction of natural glutamate. As free (unbound) glutamate, it is added to foods to enhance flavor and mimic natural umami. Like most synthetic isolates, MSG has its fair share of problems.
For example, in animal studies researchers have shown that MSG contributes to inflammation, weight-gain around the midsection, and type 2 diabetes. MSG also destroys liver tissue, leading to fibrosis, non-alcoholic fatty liver disease, and pre-cancerous lesions. (8)
MSG may also play a role in the growing problem of infertility in women. (9)
MSG has been found to increase levels of free glutamate and GABA in the brain, provoking seizures and changes in behavior. (10) Last year, researchers at Aarhus University in Demark published a study suggesting that a single dose of MSG (150 micrograms, or 3% of a teaspoon) is enough to generate headaches, elevate blood pressure, and make the muscles around the jawline more sensitive. (11)
How to Spot Hidden MSG
There are a number of processed foods that contain MSG or high levels of free synthetic glutamate.
The FDA (Food and Drug Administration) requires that food manufacturers list added MSG in the ingredients as “monosodium glutamate.” However, there are many processed foods high in MSG or free glutamate—and they require no label.
When looking at food ingredient lists, watch out for:
- Hydrolyzed vegetable protein
- Autolyzed yeast
- Hydrolyzed yeast
- Yeast extract
- Soy extract
- Protein isolate
- Natural flavor, which often contains synthetic free glutamate
What To Remember Most About This Article:
Umami is one of the five tastes of the human tongue—along with sweet, sour, salty, and bitter. Umami was first identified by Professor Ikeda at the Tokyo Imperial University in 1908. The flavor of umami may be found in soy sauce, parmesan cheese, tomatoes, and seaweed. Once Professor Ikeda discovered that the amino acid glutamate was responsible for the umami flavor, he secured a patent to produce monosodium glutamate, or MSG, in 1908.
Natural umami is one of the first flavors detected by a newborn baby in breast milk. Glutamate is the most abundant amino acid in breast milk found in naturally high concentrations to support newborn gut tissue. Glutamate further supports digestion in adults and is also an excitatory brain chemical that regulates learning and memory.
Synthetic glutamate in MSG is problematic. MSG has been linked to inflammation, type 2 diabetes, and the destruction of liver tissue. Even one dose of MSG can elevate blood pressure, cause headaches, and increase sensitivity in the muscles around the jawline.
Watch out for MSG in processed foods. MSG may be labeled as "monosodium glutamate" or listed as hydrolyzed vegetable protein, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extract, protein isolate, or natural flavor.
- Kurihara, K. (2009). Glutamate: from discovery as a food flavor to role as a basic taste (umami). The American journal of clinical nutrition, 90(3), 719S-722S.
- Giacometti, T. (1979). Free and bound glutamate in natural products. Glutamic acid: advances in biochemistry and physiology, 25-34.
- Davis, T. A., Nguyen, H. V., Garcia-Bravo, R., Fiorotto, M. L., Jackson, E. M., & Lewis, D. S. (1994). Amino Acid Composition of Human Milk Is Not unique1'2'3.
- Sarwar, G., Botting, H. G., Davis, T. A., Darling, P., & Pencharz, P. B. (1998). Free amino acids in milks of human subjects, other primates and non-primates. British Journal of Nutrition, 79(2), 129-132.
- Reeds, P. J., Burrin, D. G., Stoll, B., & Jahoor, F. (2000). Intestinal glutamate metabolism. The Journal of nutrition, 130(4), 978S-982S.
- Torii, K. (2008). Physiological role of dietary free glutamate in the food digestion. Asia Pac J Clin Nutr, 17(S1), 372-375.
- Nakamura, E., Torii, K., & Uneyama, H. (2008). Physiological roles of dietary free glutamate in gastrointestinal functions. Biological and Pharmaceutical Bulletin, 31(10), 1841-1843.
- Nakanishi, Y., Tsuneyama, K., Fujimoto, M., Salunga, T. L., Nomoto, K., An, J. L., ... & Gershwin, M. E. (2008). Monosodium glutamate (MSG): a villain and promoter of liver inflammation and dysplasia. Journal of autoimmunity, 30(1), 42-50.
- Eweka, A. O., & Om’Iniabohs, F. A. E. (2013). Histological studies of the effects of monosodium glutamate on the ovaries of adult wistar rats. Annals of medical and health sciences research, 1(1), 37-44.
- López-Pérez, S. J., Ureña-Guerrero, M. E., & Morales-Villagrán, A. (2010). Monosodium glutamate neonatal treatment as a seizure and excitotoxic model. Brain research, 1317, 246-256.
- Shimada, A., Cairns, B. E., Vad, N., Ulriksen, K., Pedersen, A. M. L., Svensson, P., & Baad-Hansen, L. (2013). Headache and mechanical sensitization of human pericranial muscles after repeated intake of monosodium glutamate (MSG). The journal of headache and pain, 14(1), 1-9.
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