Feeling Anxious, Distracted?
New Research Shows a Cup of Tea Could Help

Research scientists from top medical institutions in Asia, the Middle East, Europe and North America shared new data at the Fourth International Scientific Symposium on Tea and Human Health held in September in Washington, DC. They reviewed the latest findings on the health benefits of tea, including how it may enhance brain function, help maintain a healthy body weight, control blood sugar, and reduce risk for chronic diseases, such as heart disease and certain cancers.

Tea Theanine Link to Attention and Focus
The results of human trials presented by John Foxe, Ph.D., Professor of Neuroscience, Biology and Psychology at City College of the City University of New York, explored the effect of theanine, an amino acid present almost exclusively in the tea plan, on alpha brain-wave activity. Alpha brain rhythm is known to induce a calmer, yet more alert, state of mind.  Dr. Foxe and his team used electrophysiological measures to monitor brain activity after individuals drank solutions containing either 250 mg theanine or placebo.   "Our results showed that after having theanine, individuals showed significant improvements in tests for attention and that activity in cortical regions responsible for attention functions was enhanced," said Dr. Foxe.

New research in Dr. Foxe's laboratory, the Cognitive Neurophysiology Laboratory at the Nathan S. Kline Institute for Psychiatric Research in Orangeburg , NY, suggests that the effects of theanine in combination with caffeine are even greater than with either one alone in improving attention. Theanine may work synergistically with caffeine to help induce a more calming, relaxed state, but one that allows the mind to focus and concentrate better at tasks.  A cup of tea contains an average of 20-25 mg of theanine.

 "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 people tend to drink a cup of tea every three-to-four hours during the day," added Dr. Foxe.

Tea May Help Maintain Brain Health
Numerous studies have concluded that diets rich in fruits and vegetables support the body in fighting neurological decline through antioxidant mechanisms associated with their high flavonoid content. However, the importance of polyphenolic flavonoids in supporting healthy brain cells appears to go beyond the simple oxygen species scavenging. Pleiotropic effects on numerous biological pathways help keep human brain cells from dying and even help repair them when they are subjected to insults that damage DNA.

Human epidemiological and new animal data from around the world suggest that drinking tea, especially rich in catechins, may help support the brain as it ages. Tea consumption is inversely correlated with the incidence of dementia, Alzheimer's disease and Parkinson's disease, which may help to explain why there are significantly lower incidence rates of age-related neurological disorders among Asians than in Europeans or Americans.

Dr. Silvia Mandel, of the Eve Topf Center for Neurodegenerative Diseases in Israel, has been studying the effects of tea on brain functions in laboratory and animal models for more than a decade. Her most recent studies looked at animal models of neurological diseases, such as Parkinson's and Alzheimer's. Her group provided an amount of purified EGCG equal to about two to four cups of green tea per day to animals with induced Parkinsonism. The researchers found that when the animals are fed green Tea EGCG, the polyphenol appeared to prevent brain cells from dying and showed improvements in reducing compounds that lead to lesions in the brains of animals with Alzheimer's disease.

"Not only may the EGCG help prevent brain cells from dying, it appears that the polyphenol may even rescue the neurons once they have been damaged, to help them repair. In the past, it was thought that once brain cells were damaged, there was no way to repair them. The major question is whether these promising results are reproducible in humans," says Dr. Mandel.

Tea and Weight Management
With two-thirds of the U.S. adult population overweight or obese, scientists are looking for medically sound ways to manage weight.  One area of intense research is green tea, specifically catechin polyphenols. Eva Kovacs, Ph.D., Clinical Research Manager at Unilever North America, reviewed the existing scientific literature on green tea, weight loss, and metabolism.  Dr. Kovacs reviewed recent studies that suggest green teas may aid in weight management, possibly through increased resting energy expenditure and fat oxidation. "A few studies have found modest benefits on metabolism from green tea extract, but more research is needed before recommending drinking green tea as a 'fat burner,'" said Dr. Kovacs.

Tea drinkers may find that they can eliminate liquid calories in their diet by drinking tea in lieu of sugar-laden beverages that are nutrient-poor but calorie-rich.  Dr. Kovacs warned consumers that green tea products are no magic bullet for weight loss.

Tea Consumption Tames Inflammation, Improves Blood Vessel Function
Research presented by Claudio Ferri, M.D., Professor of Internal Medicine at the University of L'Aquila, Italy, provided insights into how tea flavonoids provide support for cardiovascular health by promoting healthy endothelial function.  In his studies, subjects were given low, intermediate, or high doses of tea flavonoids.  "Our studies have found that tea flavonoids improved endothelium-dependent vasorelaxation and decrease arterial stiffness in study participants, thereby suggesting that tea consumption may have favorable effects on cardiovascular disease," he said.

These new developments in artery endothelium research add to the growing body of evidence suggesting that drinking as little as two to four cups of tea daily can promote cardiovascular health. Tea flavonoids are thought to support cardiovascular health through several mechanisms, including: providing antioxidants to help temper inflammatory markers such as C-reactive protein, reducing blood cholesterol levels, and providing dilation of blood vessels to help manage blood pressure.

Tea May Impact Genes Involved in Cancer Initiation and Development
Results from trials on the role of green tea in the prevention of cancer provided insights into the cutting-edge field of nutri-genomics, or how gene susceptibility to chronic diseases can be altered through dietary interventions.  Iman Hakim, M.D., Ph.D., M.P.H., Professor and Interim Dean of the Mel and Enid Zuckerman College of Public Health and Professor at the Arizona Cancer Center, University of Arizona, has conducted human clinical trials over the past decade on the role green and black tea may play in certain cancers. Her latest human clinical trial suggests that bioactive compounds in tea have a significant effect on genes that impact cancer susceptibility and repair from environmental insults.

 "We are seeing that green tea is impacting genes that play a role in cancer, but we cannot at this point pinpoint who will be responders versus non-responders," said Dr. Hakim.  "In addition, our recent preliminary data show a beneficial effect of green tea on lipid profile among smokers and former smokers."  Dr. Hakim's lab is currently analyzing the study data to determine if black tea has similar effects. Sherecommends at least four cups of tea per day.

Tea Drinkers Consume 20 Times More Flavonoids
Flavonoids are a type of antioxidant found primarily in plant-based foods and beverages, including chocolate, wine and tea.  Intake of flavonoids has been inversely associated with the incidence of many chronic diseases. Using the latest national food consumption databases and the USDA Flavonoid Database, Michigan State University researchers were able to differentiate tea drinkers from non-tea drinkers and analyze their diets for flavonoid intake.  "We found that just over 21 percent of U.S. adults drank tea and that the total flavonoid intake of tea consumers was more than 20 times higher than flavonoid consumption of non-tea drinkers," explained lead researcher Won Song, Ph.D., R.D. Professor of Human Nutrition at Michigan State University.

Tea drinkers averaged nearly 700 mg flavonoids while non-tea drinkers averaged about 33 mg per day.  A cup of tea contains approximately 125 mg flavonoids, which is more than most non-tea drinkers consume in an entire day.

Edited by Patricia D. Sherman

©TeaAtlas.com

Contact Us: Editor Webmaster