Additional Information on L-Theanine 

Stress and Anxiety

Stress and anxiety are debilitating conditions that can shorten life span while lessening performance, well being, and the enjoyment of life. Stress can impair the ability to perform mentally. It may result in reactions to situations that cause enhanced frustration, hostility or even injury. Stress slowly destroys the immune system, lowering resistance to disease and thus allowing degenerative and opportunistic diseases to occur. Stress is a cause of depression. The entire population is subjected to stress. In a 1998 survey, nearly 65 percent of the adult population indicated that they were under great stress. More than 23 million Americans suffer from anxiety illness.

PMS

Studies in cooperation with Taiyo Kagaku Co., The University of Shizuoka, and The Family Planning Institute of Japan have shown that women taking 200 mg L-theanine daily have lower incidence of PMS symptoms. These symptoms include physical, mental, and social symptoms. Overall, a significant alleviation of PMS symptoms by L-theanine was observed.

Brain Chemical May Thwart Ravages of Aging: Study
L-theanine appears to have a role in the formation of the inhibitory neurotransmitter Gamma Amino Butyric Acid (GABA). GABA blocks release of the neurotransmitters dopamine and serotonin, playing a key role in the relaxation effect.

By Keith Mulvihill

NEW YORK (Reuters Health) - A shot of a brain chemical called GABA essentially turned back the clocks in the brains of older monkeys, whose brain function briefly operated at levels normally seen in monkeys less than half their age.

The finding may one day help scientists reverse similar age-related deterioration in the brains of people, according to the report published Friday in the journal Science.

GABA, or gamma-aminobutyric acid, is a messenger chemical that is essential for optimizing how brain cells transmit messages to each other and acts to put a damper on unwanted brain signaling activity, explained the study's lead author Dr. Audie G. Leventhal at the University of Utah School of Medicine in Salt Lake City.

Although GABA's age-related decline has not been documented in humans, a host of studies in mammals, including other primates, suggests that a similar process is at work in people, explained Leventhal.

In the current study, Leventhal's team evaluated how a brain region called the visual cortex in old and young monkeys responds to micro-shots of GABA.

Monkeys between the ages of 26 and 32 -- considered very old for monkeys -- that got GABA directly delivered to their neurons responded to visual patterns, such as flashing vertical and horizontal lines, in much the same way as monkeys aged 7 to 9 years old did, according to Leventhal.

Without GABA delivery, the monkeys' aged brains had more difficulty firing neurons that specifically gauge various aspects of depth perception, motion and color, explained Leventhal. Instead, older monkeys have more random firings that make it difficult to observe visual nuances.

In younger monkeys, GABA had no effect since their brains already had optimal GABA functioning.

"The challenge now is to go and look at a variety of GABA-increasing drugs and see how they influence other areas of the brain" and whether or not they improve brain functions known to decline as people age, such as hearing and memory, said Leventhal.

"It may be that already approved GABA (boosting drugs) have a positive effect on mental decline in the brains of older adults, but nobody has ever looked," he told Reuters Health.

Nonetheless, the findings raise some hope that a general decline in GABA may be correctable, explained Leventhal, who noted that people are born and die with the same nerve cells and more research should be conducted in preserving their function.

SOURCE: Science 2003;300:812-815.

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