Of all the supplements that the great and powerful Oz has spoken about on his popular syndicated TV show, L-theanine has elicited some of the most exciting responses from his viewers and consequently, our customers. Let's face it, unless your name is Cheech, and you've got an alternative strategy, almost everyone must manage a certain amount of stress in their lives, and a supplement that can help us cope with this stress, especially in these uncertain economic times is L-theanine.
L-theanine is a free (non-protein) amino acid found almost exclusively in tea plants, 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.
Green tea’s calming effect 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.
First, 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.
The regulation of blood pressure is partly dependent upon catecholaminergic and serotonergic neurons in both the brain and the peripheral nervous system. Studies on spontaneously hypertensive rats showed an impressive blood pressure lowering effect with L-theanine. The lowered blood pressure effect was dose-dependent with the highest test dose creating the most significant drop. L-glutamine was used as one of the controls. Although L-glutamine is similar in chemical structure to L-theanine, it did not exhibit an anti-hypertensive effect. Preliminary studies report that L-theanine has been found to increase the anti-tumor activity of some chemotherapeutic agents (doxorubicin and idarubicin) and to ameliorate some of the side effects of these drugs. It appears to increase the inhibitory concentration of these drugs in the tumor cells, although the mechanism is not known. At the same time, L-theanine decreased oxidative stress caused by these agents on the normal cells, possibly due to its mild antioxidant activity.
Stress and anxiety are debilitating conditions that upset the balance of our hormones leading to a loss of our well-being, performance—even lifespan. Stress impairs the immune system, leaving us vulnerable to opportunistic infections, and can cause depression. In 1998, pharmaceutical sales of anti-anxiety drugs totaled over 700 million dollars, while sales of antidepressants totaled close to 5 billion dollars! People under stress can mitigate many of the harmful effects of stress with L-theanine without becoming sedated in the process. It should be noted that if an individual were already relaxed, taking L-theanine would not produce further relaxation.
Research into L-theanine is derived from the contradictory observation that green tea, with its high caffeine content, produces a very calming effect. The seemingly multi-dimensional reasons for this relaxation effect will continue to be studied. Current areas of ongoing research include using L-theanine to calm hyperactivity in children and adults, as support for PMS sufferers, to support healthy blood pressure levels, to sharpen mental acuity and concentration, and as an anti-cancer agent alone and in synergy with other cancer-fighting agents. L-theanine may find another area of application in reducing the negative side effects of caffeine brought on by the over-consumption of coffee, soft drinks, or other caffeine-containing substances.
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