Neurologically-active amino acid in tea called L-theanine ...

Neurologically-active amino acid in tea called L-theanine (gamma-ethylamino-L-glutamic acid).

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L-theanine is a free (non-protein) amino acid found almost exclusively in tea plants (Camellia sp.),
constituting between 1 and 2-percent of the dry weight of tea leaves. It is the predominant amino acid in
green tea leaves, giving tea its characteristic umami or "5th taste" (besides the four traditional tastes:
sweet, salty, acid, and bitter). Attempts to isolate the L-theanine, with its physical and neurological
benefits, from the tea leaves were once difficult, expensive, and inefficient. Economically feasible
methods of producing the identical L-theanine now exist and do not require a mountain of tea leaves.

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Physiological Effects

The calming effect of green tea may seem contradictory to the stimulatory property of tea's caffeine
content but it can be explained by the action of L-theanine. This amino acid actually acts antagonistically
against the stimulatory effects of caffeine on the nervous system. (1) Research on human volunteers has
demonstrated that L-theanine creates a sense of relaxation in approximately 30-40 minutes after ingestion
via at least two different mechanisms. First, this amino acid directly stimulates the production of alpha
brain waves, creating a state of deep relaxation and mental alertness similar to what is achieved through
meditation. Second, L-theanine is involved in the formation of the inhibitory neurotransmitter, gamma
amino butyric acid (GABA). GABA influences the levels of two other neurotransmitters, dopamine and
serotonin, producing the key relaxation effect. (2)

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Alpha Brain Activity

The brain emits weak electrical impulses (brain waves) that can be measured on the surface of the head.
The predominant frequency of electrical impulses correlates with different types of mental states and
activities. Brain waves are classified into four categories (delta, theta, alpha, and beta)—each with an
associated mental state (Fig. 1). Delta is seen only in the deepest stages of sleep. Theta is seen in light
sleep and drowsiness. Alpha is present in wakefulness where there is a relaxed and effortless alertness and
Beta is seen in highly stressful situations and where there is difficulty in mental concentration and focus.
It is well known that alpha brain waves are generated during a relaxed state and therefore alpha waves are
used as an index of relaxation.

http://web-us.com/l-theanine_anxiety_reducer.htm

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L-theanine may help relieve stress by inducing a relaxing effect without drowsiness. L-theanine as been
shown to promote the generation of alpha-brain waves, an index of relaxation. It may also boost natural
resistance to microbial infections and perhaps even tumors. Researchers suggest further isolating and
refining L-theanine from tea to use it as a drug to boost the infection defense of the body. Although
limited, there is clinical evidence to support these claims.

http://www.drugs.com/npc/l-theanine.html

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Theanine (delta-glutamylethylamide) is one of the predominant amino acids ordinarily found in green tea,
and historically has been used as a relaxing agent. The current study examined the acute effects of L-
theanine in comparison with a standard benzodiazepine anxiolytic, alprazolam and placebo on
behavioural measures of anxiety in healthy human subjects using the model of anticipatory anxiety (AA).
Sixteen healthy volunteers received alprazolam (1 mg), L-theanine (200 mg) or placebo in a double-blind
placebo-controlled repeated measures design. The acute effects of alprazolam and L-theanine were
assessed under a relaxed and experimentally induced anxiety condition. Subjective self-reports of anxiety
including BAI, VAMS, STAI state anxiety, were obtained during both task conditions at pre- and post-
drug administrations. The results showed some evidence for relaxing effects of L-theanine during the
baseline condition on the tranquil-troubled subscale of the VAMS. Alprazolam did not exert any
anxiolytic effects in comparison with the placebo on any of the measures during the relaxed state. Neither
L-theanine nor alprazalam had any significant anxiolytic effects during the experimentally induced
anxiety state. The findings suggest that while L-theanine may have some relaxing effects under resting
conditions, neither L-theanine not alprazolam demonstrate any acute anxiolytic effects under conditions
of increased anxiety in the AA model. 2004 John Wiley & Sons, Ltd.

http://www.ncbi.nlm.nih.gov/pubmed/15378679?dopt=AbstractPlus

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But green tea has another naturally occurring compound that’s worthy of attention and praise, the amino
acid L-theanine. Although it’s not an antioxidant, L-theanine has been shown to:

Have a calming effect

Protect and restore the brain

Stimulate the immune system, and even make cancer chemotherapy more effective with fewer side
effects.

Induce deep states of relaxation without sedation

Relieve some PMS and menopausal symptoms

Increase focused attention and improve learning

Relieve nicotine addiction

Prevents jitters caused by caffeine (while increasing mental clarity)

Promote sleep

Calm and Focused: How Does L-Theanine Work?

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L-theanine has several advantages over prescription medications and herbs. It helps you feel calm without
feeling drowsy and mentally alert without feeling jittery. And although research to date has been limited,
L-theanine has few if any side effects.

According to Carolyn Perrini, CLS, CNC in her article “L-Theanine: How a Unique Anxiety Reducer and
Mood Enhancer Increases Alpha Waves and Alertness, “L-theanine acid stimulates the production of
alpha brain waves, creating a state of deep relaxation and mental alertness similar to what is achieved
through meditation. Second, L-theanine is involved in the formation of the inhibitory neurotransmitter,
gamma amino butyric acid (GABA). GABA influences the levels of two other neurotransmitters,
dopamine and serotonin, producing the key relaxation effect.”

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http://naturalmedicine.suite101.com/article.cfm/green_tea_and_ltheanine_natural_anxiety_relief

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