WASHINGTON, Sept. 18 Leading scientists from around theworld convened today in Washington, DC for the Fourth International ScientificSymposium on Tea & Human Health to review the latest findings on the potentialhealth benefits of tea, including studies on how it may help maintain ahealthy body weight, control blood sugar and even help us think more clearly.New studies adding to the body of knowledge regarding the comfort beverage'spotential ability to reduce risk for several chronic diseases, such as heartdisease and certain cancers were also presented.
Tea Theanine Link to Attention and Focus
The results of several ongoing human trials presented by John Foxe, Ph.D.,Professor of Neuroscience, Biology and Psychology at City College of the CityUniversity of New York, have found that theanine from tea actively alters theattention networks of the brain. Theanine is an amino acid present almostexclusively in the tea plant. After drinking tea, the amino acid theanine,which is present in Green, Black and Oolong varieties, is known to be absorbedby the small intestine and cross the blood-brain barrier where it affects thebrain's neurotransmitters, and increases alpha brain-wave activity. Thisalpha brain rhythm is known to induce a calmer, yet more alert, state of mind.
Dr. Foxe and his team used electrophysiological measures to monitor brainactivity after individuals drank solutions containing either 250 mg theanineor placebo. The subjects were asked to complete a variety of attention-related computerized tasks. "Our results showed that after having theanine,individuals showed significant improvements in tests for attention and thatactivity in cortical regions responsible for attention functions wasenhanced," said Dr. Foxe.
New research in Dr. Foxe's laboratory, the Cognitive NeurophysiologyLaboratory at the Nathan S. Kline Institute for Psychiatric Research inOrangeburg, New York, suggests that the effects of theanine in combinationwith caffeine are even greater than with either one alone in improvingattention. Theanine may work synergistically with caffeine to help induce amore calming, relaxed state, but one that allows the mind to focus andconcentrate better at tasks. A cup of tea contains an average of 20-25 mg oftheanine.
"What's more, we have seen that just 20 minutes after consuming theanine,the blood concentrations increase and the brain's alpha waves are impacted.It lasts about three to four hours, which we have speculated may be why peopletend to drink a cup of tea every three-to-four hours during the day," addedDr. Foxe.
Tea May Help Maintain Brain Health
Numerous studies have concluded that diets rich in fruits and vegetablessupport the body in fighting neurological decline through antioxidantmechanisms associated with their high flavonoid content. However, theimportance of polyphenolic flavonoids in supporting healthy brain cellsappears to go beyond the simple oxygen species scavenging, involvingpleiotropic effects on numerous biological pathways to help keep human braincells from dying and even help repair them when they are subjected to insultsthat damage the cells' DNA.
Human epidemiological and new animal data from around the world suggestthat drinking tea, especially rich in catechins, may help support the brain aswe age. Indeed, tea consumption is inversely correlated with the incidence ofdementia, Alzheimer's disease and Parkinson's disease, which may help toexplain why there are significantly lower incidence rates of age-relatedneurological disorders among Asians than in Europeans or Americans.
Dr. Silvia Mandel, of the Eve Topf Center for Neurodegenerative Diseasesin Israel, has been studying the effects of tea on brain functions inlaboratory and animal models for over a decade. Her most recent studies,presented at the symposium, looked at animal models of neurologic