Was it this special amino acid which set in motion the past millennia of green tea connoisseurship in Japan, and now the rest of the world? While many think of tea, e.g. black, green, or white tea, as stereotypes of a softer caffeine temperament, or for those who don’t quite need the whole-kick of a morning coffee, it’s wrong of those who assume such limited virtues.
All tea is produced from the Camellia sinensis shrub, which under variable circumstances, can be prepared into the spectrum, or grades, found between matcha, green, white, and black teas. As you’ll find out, caffeine alone wouldn’t explain such diversity, and in fact no tea expertise is complete without acknowledging the incredible benefits of L-theanine, something that unlike tea, no coffee in the world can claim to contain.
First of all, this amino acid is unique to the tea plant, originally isolated in Japan from gyokuro, a type of premium Japanese green tea. It can also be thought of as a flagship to the dynamic between health benefits and countless other natural compounds, antioxidants (e.g. EGCG), nutrients, and amino acids found in tea. L-theanine’s acclaim stems from two important reasons: One, its influence on taste, providing a deep umami accent in tea flavor, and two, as an immense benefit to our psychological, and physiological well being.
Also good for context, not all tea possesses the same levels of L-theanine. Black teas typically contain the least, in place of higher caffeine content. On the other hand, green teas, but especially matcha due to precise growing conditions, are known to contain upwards of five times the normal levels of L-theanine. As matcha developed as a custom of Japanese Zen Buddhism nearly a millennia ago, we’re left to wonder if L-theanine’s favorable taste, or favorable effects are responsible for the cultivation of today’s best Japanese matcha.
More than likely it was the effects, after all, the Zen Buddhists who developed matcha in the pursuit of heightened meditative states were highly attuned to their psychological and physiological happenings. Zen monks naturally began associating special effects with savory flavor, and began to selectively root-out the most exquisite matcha cultivars alongside a specialized school of growing practices. In a tradition which continues in Japanese matcha tea-fields today, pre-harvest shading up to three weeks before hand-picking, allows for the most robust composition of L-theanine, potent antioxidants like EGCG, and valuable nutrients.
As clinical evidence today supports, our historical Zen practitioners were onto something. Numerous research publications recognize the L-theanine contained in matcha as a promoter of calm, relaxation, and alpha-brain waves. Among other studies, matcha’s L-theanine is suggested to improve sleep, focus, learning, and symptoms of anxiety. If that wasn’t enough, it has also withstood scrutiny as a neuroprotective and cardioprotective compound, with additional functions in modulating immune and neurotransmitter responses.
Yet, beyond any basic summary of health claims or study outcomes, it is far superior to familiarize oneself with just how exactly something so little, can do so much. It is true that most modern clinical research has precipitated from inquiries to the natural synergy between L-theanine as a conjunct to caffeine (both naturally occurring in matcha), but modern pharmacology holds many more of the answers we seek.
What’s happening in the body
As a ‘non-essential amino acid’ L-theanine is an analogue, or close structure, to its protein-building counterparts L-glutamate and L-glutamine, both of which are critical to normal protein synthesis and balanced neurotransmitters. In the body it is absorbed by the small intestine and can be converted by the liver into active L-glutamate; however some L-theanine that is consumed isn’t first broken down, instead it can cross the blood brain barrier (BBB) to modulate many of the same glutamate receptor sites. It’s important that you know, glutamate is the most abundant excitatory neurotransmitter in the brain and central nervous system. Excitatory neurotransmitters require a careful balance in the brain in order to avoid excitotoxicity and hypofunction, i.e. serious imbalances in neurotransmitters.
Multiple studies have assessed L-theanine’s promising neuromodulating effects, one in particular being by reducing glutamatergic excitotoxicity by acting as a glutamate reuptake inhibitor. The latest science also recommends L-theanine as a powerful modulator on NMDA receptors, acting as an agonist (to increase activity). These receptors are involved in memory, learning, proper muscle impulses, and can signal the production of other neurotransmitters. When underfunctioning however, they make it difficult to avoid distractions, counter impulses, and they’ve even been associated with cognitive disorders such as schizophrenia. Overall, this amino acid helps to bear the brunt in the host of important functions of the chemically similar, and physiologically critical glutamate.
Matcha’s L-theanine doesn’t stop there, it has also been implicated in important biomarkers for brain health, neuronal growth, and in developing a more homeostatic condition between important neurotransmitters other than glutamate, e.g. dopamine and serotonin. Multiple peer reviewed studies demonstrate that L-theanine triggers an increased production of dopamine and serotonin in key regions in the brain by encouraging production of transmitter precursors such as tryptophan. L-theanine has also been found to bind to the glutamatergic AMPA receptor, encouraging the release of GABA which plays an overwhelmingly important role in the brain; it functions as a chief inhibitory signal for relaxation, muscle tone, and focus, while also protecting from a broad range of excitotoxicity.
Beyond protection, L-theanine increases plasma levels of BDNF (Brain Derived Neurotrophic Factor) and NGF (Nerve Growth Factor). For one, BDNF is associated with glutamate activity and strongly defines brain health, especially in terms of neuroplasticity and impulse control. Also, and as suggested through many shared glutamatergic mechanisms, controlled studies have determined that NGF is upregulated by L-theanine, primary roles including the maintenance, growth, and healing of neurons. Reports point to appropriate levels of NGF, as aided by L-theanine, in the prevention and reduced symptomology of neurodegenerative diseases such as Alzheimer’s and Parkinson’s Disease.
Ancient Zen monks as well as modern Japanese have shared in impressive feats of longevity, minimal disease and age-related cognitive impairments, qualities greatly attributed to the ingestion of matcha green tea at least 2, or even 3 times each day. Cutting-edge scientific figures coincide this level of consumption with the threshold levels of therapeutic benefits not only from L-theanine, but also antioxidant catechins like EGCG. Although you’ll begin to feel these effects build from ‘Day 1,’ two average servings of matcha, each day, for at least three months is recommended to fully incorporate catechin-based improvements in metabolic and cognitive function, detoxification, increased thermogenesis, and caloric output, as well as L-theanine’s range of central nervous system modulating properties mentioned.