Benefits of the non-essential amino acid: L- Theanine

Marianna Nakos
3 min readOct 11, 2023

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Theanine comes in two forms: L-theanine and D-theanine and is an amino acid found in tea and some mushrooms. L-theanine is the most common form.

L-theanine was discovered in 1949 in the leaves of green tea specifically from the leaves of the Camellia sinensis plant. Although it has also been identified in some mushrooms, tea is the primary naturally occurring source of L-theanine. This amino acid is responsible for a unique taste constituent of the tea, producing a caramel flavor and an attractive aroma and that helps to alleviate tea polyphenols.

It might affect the levels of certain chemicals in the brain such serotonin and dopamine. These influence mood, sleep, and emotion, and cortisol, which helps the body deal with stress. It has a chemical structure similar to glutamine (GABA and glutamate), producing its own calming, anxiety-reducing effects.

Benefits of L-Theanine:

  • It helps increase focus
  • It lowers cholesterol
  • It improves gut health

Which are the different amino acids?

There are three categories of amino acids: essential, nonessential, and conditional amino acids. Our bodies do not have the capacity to manufacture the (9) essential amino acids and they receive them from the food we eat. The body can manufacture the (11) nonessential amino acids (alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine and tyrosine) from the essential amino acids supplied via food or during protein breakdown. Conditional amino acids are needed during certain conditions and are only considered essential when you’re ill or stressed.

Which foods have all 9 essential amino acids?

Foods that contain all nine essential amino acids are called complete proteins.

  • beef (+ B-vitamins, zinc, and iron)
  • poultry (+ iodine, iron, zinc, vitamins (especially B12)
  • fish (+ heart healthy fatty acid, Omega 3s, is found in salmon)
  • eggs (+high in vitamins A, D, E, K, B2, B6, B12 and minerals such as zinc, iron and copper)
  • Soybeans (+ vitamin K, vitamin B1, and omega 3s)
  • quinoa (+high in fiber, magnesium, B vitamins, iron, potassium, calcium, phosphorus)
  • buckwheat (less concentrated than meat)
  • blue-green algae (+ lowers cholesterol or other fats (lipids) in the blood)

Why do we need amino acids?

Your body uses amino acids to make proteins. The different types of amino acids and the way they’re put together determine the function of each protein. So, amino acids are involved in many important roles in your body. Amino acids help:

  • Break down food
  • Grow and repair body tissue
  • Make hormones and brain chemicals (neurotransmitters).
  • Maintain healthy skin, hair and nails
  • Build muscle
  • Boost your immune system
  • Sustain a normal digestive system

Overall, despite not being considered an essential amino acid, L-theanine offers a range of health benefits that make it a valuable dietary supplement. t is well-tolerated and has a favorable safety profile, making it a popular choice among those looking to enhance their well-being and cognitive performance.

However, as with any supplement, it’s essential to consult with a healthcare professional before incorporating L-theanine into your daily routine, especially if you have any underlying medical conditions or are taking medications.

https://www.sleepfoundation.org/sleep-aids/l-theanine-for-sleep#:~:text=L%2Dtheanine%20is%20found%20in,occurring%20source%20of%20L%2Dtheanine

https://www.sciencedirect.com/science/article/abs/pii/S0753332217336569#:~:text=l%2Dtheanine%20was%20discovered%20in,and%20caffeine%20bitterness%20%5B11%5D.

https://examine.com/supplements/theanine/

https://www.ncbi.nlm.nih.gov/books/NBK234922/#:~:text=Nine%20amino%20acids%E2%80%94histidine%2C%20isoleucine,called%20the%20essential%20amino%20acids.

https://my.clevelandclinic.org/health/articles/22243-amino-acids

https://www.webmd.com/vitamins/ai/ingredientmono-1053/theanine

https://www.piedmont.org/living-better/what-is-a-complete-protein

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