Take a chill pill

Theanine

Hoffman Center Staff

Clinical Nutritionist for the Hoffman Center

Faculty member of the American College for the Advancement in Medicine

Avoid Karoshi! In Japansese, karoshi means "death from over work." Stress is legendary in Japan -- so much so that according to Labor Ministry statistics there had been twenty-one case of karoshi in 1987, twenty-nine cases in 1988 and thirty cases in 1989. But a liaison council of attorneys established in 1988 to monitor deaths from overwork estimated in 1990 that over 10,000 people were dying each year from karoshi.

Theanine, an amino acid found in tea, seems to take the "buzz" out of caffeine. Imagine what would happen if theanine were extracted from tea and given as a supplement. Well, this is exactly the case in Japan. Over 50 food items (except baby food) have theanine as an added ingredient. Everything from boxed cereal to chewing gum has been "spiked" with the relaxing tea extract. What is known about the effects of theanine to warrant such broad spectrum ‘fortification’?

The relaxing effects of theanine are indeed quite real. Studies have shown that theanine can take the "worry" out of one’s head by acting on some critical pathways in the brain. First we need to understand a little neurobiology to get a better idea of why theanine is a true "chill pill". Theanine increases GABA (gamma-amino-butyric acid), an important inhibitory neurotransmitter in the brain. GABA can be considered the brain’s natural sedative that brings balance to excitability that can sometimes lead to restlessness, insomnia, and other disruptive conditions. Theanine also increases levels of dopamine, another brain chemical with mood-enhancing effects.

The technical stuff

Theanine is the predominant amino acid of tea, and accounts for 50% of the total free amino acids found in tea. It was first discovered in an aqueous extract of green tea leaves, later it was reported in other forms of tea. It was shown that theanine was synthesized in the tea roots and then proceeded to the developing shoot tips under the catalytic avtivity of a specific enzyme, L-glutaminate ethylamine ligase, and using the amino acid alanine as the precursor of ethylamide. This process is accelerated by light. The chemical structure was proven to be gama-ethylaminde of glutamic acid. The amount of theanine in tea is dependent upon the cultivation process, growing conditions and type of tea. It seems that black tea contains the highest quantity of theanine and the total content of theanine in the different types of black tea have been divided into three groups, high, medium and low. Darjeeling Gastelton black tea contains the highest quantity of theanine (250 mg, per 100 grams).

The first pharmacological effects upon human metabolism were studied by Walter Freldheim et al at the Department of Human Nutrition, University of Kiel, W. Germany. Every wonder why tea contains caffeine yet doesn’t give you the same kick as a cup of coffee? This fledgling research seemed to indicate that theanine reduced the stimulating action of caffeine.

What health conditions benefit from theanine?

Just as meditation, massage, or aromatherapy quiets the mind and body, so too theanine plays a role in inducing the same calm and feeling of well-being. Below are some health conditions that would benefit from supplemental theanine.

This natural supplement has also shown promising results in controlling the symptoms of Premenstrual Syndrome (PMS). A Japanese study tracked the reactions of women taking this non-toxic, safe supplement for two months in doses of 100 mg twice a day. The researchers documented reductions in mental, social, and physical symptoms associated with PMS.

Theanine has been shown to clinically lower blood pressure. I routinely add it to my hypertensive patient protocols at the Hoffman Center.

Based on studies on neurons in cell culture, theanine has been linked to the significant reversal of glutamate-induced toxicity, a major cause of degenerative brain disease.

Since theanine is an active ingredient in green tea, this naturally occurring supplement may also play a role in cancer prevention. In Japan where green tea is a popular beverage, surveys showed that people who consumed green tea had much lower incidence of liver, pancreatic, breast, lung, esophageal and stomach cancer.

Theanine is showing some promising results in cancer research. Two new studies show that the inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of Doxorubicin (Doxorubicin is chemotherapy that is given as a treatment for many different types of cancer). The second study showed that theanine increases the Idarubicin -induced antitumor activity and reduces associated toxicities (Idarubicin is chemotherapy that is given as a treatment for some types of cancer. It is most commonly used to treat breast cancer, and some types of leukemia).

Theanine can "brew" up an immune response. In two studies theanine was shown to increase the human immune response to viruses, bacteria and fungi. Theanine is a precursor to a substance called alkylamine, which are also present in some bacteria, cancerous cells, parasites, fungi, and other disease-causing agents.

By taking theanine one may be able to prime the body's immune system against these agents, by teaching disease-fighter immune cells to recognize and remember alkylamines.

Another study at Brigham and Women's Hospital in Boston and Harvard Medical School revealed that L-theanine is broken down in the liver to ethylamine, a molecule that primes the response of an immune blood cell called the gamma-delta T cell.

We know from other studies that gamma-delta T cells in the blood are the first line of defense against many types of bacteria, viral, fungal and parasitic infections. The T cells prompt the secretion of interferon, a key part of the body's chemical defense against infection. Bottom line — taking theanine to relax, might increase your immune response!

I’m sure it’s obvious by now that it could also be employed in a hyperactive/stress condition. Attention deficit and hyperactivity disorders, insomnia, panic and anxiety attacks, obsessive compulsive disorder and anger management would all benefit from theanine therapy.

How do I take it?

We have a very interesting approach to dosing theanine. We have used the general recommendation of 100mg, three times per day, with or without food. However, I prefer to measure GABA levels via a urine test (as part of a full neurotransmitter panel) so I can see how much theanine is required to reach a therapeutic range (it is my clinical opinion that 15 to 35 ug/gCr is a therapeutic range). This way I can be very accurate with dosage, and monitor results. After urine testing GABA levels, I dose from 100mg to 600mg per day.

Got tea?

Last time I put my thoughts to the computer screen I wrote an article on EGCG, the potent antioxidant from green tea. Here I am at it again with an article on another extract of tea with additional benefits. New research is showing that yet another substance from tea, specifically black tea, called theaflavins, may lower total cholesterol and raise HDL. The point I’m trying to drive home is that tea seems to contain a wealth of healthy compounds that are just beginning to be explored. I don’t know about you, but I believe all doctors should recommend regular tea consumption to their patients, and explore the wonderful extracts available within their leaves of health.

References

Abe Y, et al. 1995. Effect of green tea rich in gamma-aminobutyric acid on blood pressure of Dahl salt-sensitive rats. Am J Hypertens 8:74-9.

Cardiovascular risk factors among Japanese and American telephone executives. Int J Epidemiol 6:7-15, 1977.

Comstock GW, et al. 1985. Cardiovascular risk factors in American and Japanese executives. Telecom Health Research Group. J R Soc Med 78:536-45.

Juneja LR, et al. 1999. L-theanine—a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Tech 10:199-204.

Kakuda T, et al. 2000. Inhibiting effect of theanine on caffeine stimulation evaluated by EEG in the rat. Biosci Biotech Biochem 64:287-93.

Kakuda T, et al. 2000. Protective effect of -glutamylethylamide (theanine) on ischemic delayed neuronal death in gerbils. Neurosci Lett 289:189-92.

Kobayashi K, et al. 1998. Effects of L-theanine on the release of -brain waves in human volunteers. Nippon Noegik Kaishi 72:153-57.

Sadakata S, et al. 1992. Mortality among female practitioners of Chanoyu (Japanese "tea-ceremony"). Tohoku J Exp Med 166:475-77.

Sesso HD, et al. 1999. Coffee and tea intake and the risk of myocardial infarction. Am J Epidemiol 149:162-7. Simons LA, et al. 1992. Health status and lifestyle in elderly Hawaii Japanese and Australian men. Exploring known differences in longevity. Med J Aust 157:188-90.

Yokogoshi H, et al. 1998. Hypotensieve effect of -glutamylmethylamide in spontaneously hypertensive rats. Life Sci 62:1065-68.

Yokogoshi H, et al. 1995. Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Biosci Biotech Biochem 59:615-18.

Toxicol Lett 2001 Apr 30;121(2):89-96

Cancer Lett 2000 Oct 1;158(2):119-24

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