Theanine (N-ethyl-gama-glutamine) is a novel non-protein amino acid, rare in nature but found in tea (Camellia sinensis) and a common mushroom called Boletus badius. This amino acid has a molecular weight of 174.2 grams/mole and the formula C7H14N2O3. Theanine is a chiral molecule so mirror image versions are possible. In nature, the L-form is dominant. It was discovered by the Japanese in 1949 and has been synthesized enzymatically for commercial production since 1964.
Green Tea and Theanine
In nature, theanine is most commonly found in tea leaves where it may be up to 50% of the amino acids, and 2% of the dry weight. Contrary to popular thought, research indicates that theanine is more abundant in the older leaves while caffeine and epigallocatechin gallate (EGCG) are more abundant in the young leaves and apical buds.
Theanine contents of tea are not equal. Mass produced black teas are generally of low quality and contain less than 10 mg per cup, while high quality green teas contain much more. High quality oolong and matcha teas are the best bets and may contain upwards of 50 mg a cup. Theanine is said to give quality teas a distinct, fifth, “frothy” taste separate from sweet, sour, salty, and bitter.
Physiological Effects of Theanine
Theanine has many positive physiological effects:
- Decreases blood pressure and heart rate
- Liver Protective
- Decreases appetite and obesity
- Improves mood and decreases feelings of anxiety
- Improves focus and learning ability
- Improves post-exercise mental and cognitive recovery
- Neuro-protective qualities
- Immune system stimulation
- Suppresses tumors and aids chemotherapy in cancer treatment
The active, bio-available form of this molecule appears to be the L-form (L-theanine). It is absorbed readily and moves into the blood stream within 30 minutes of ingestion. Theanine seems to blunt the effects of caffeine and attenuates the sympathetic component of the central nervous system (CNS). It readily crosses the blood brain barrier where it aids cognitive functions like clarity, focus, and mood. These properties are enhanced in a synergistic fashion when combined with the substance called honokiol extracted from magnolia bark. Theanine also seems to aid in the chemotherapeutic treatment of some cancers while reducing the side-effects of adjunct drugs like doxorubicin. It enhances the abilities of special white blood cells called T-lymphocytes which are then primed to be much more sensitive to cancer cells and microbes.
Dosage Recommendations for Theanine
While positive cognitive results have been substantiated at 50 mg/day, the recommended dosage for theanine (L-theanine) appears to be between 50 and 200 mg/day. This can easily be obtained with a cup or two of quality green tea or supplements obtained from the local health food store. While multiple studies show it to be non toxic, some anecdotal reports indicate that dosages over 300 mg may cause light-headedness.
Supplemental Research;
Food Chem Toxicol. 2006; 44(2):286-92 (ISSN: 0278-6915) Sadzuka Y; Sugiyama T; Nagamine M; Umegaki K; Sonobe T
Biol Pharm Bull. 2005; 28(9):1702-6 (ISSN: 0918-6158) Sadzuka Y; Inoue C; Hirooka S; Sugiyama T; Umegaki K; Sonobe T
Nutr Rev. 2008; 66(2):96-102 (ISSN: 0029-6643) Bukowski JF ; Percival SS
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