Tea's Healthy AttitudeWellness takes stage at symposium
By Bruce Richardson
One of the many marvels of tea is the seeming contradiction that this ancient beverage calms the mind as it stimulates our ability to concentrate. This phenomenon was one of several topics covered at the Fourth International Scientific Symposium on Tea and Human Health, held in September at the Department of Agriculture in Washington, D.C.
Tea’s ability to both calm and stimulate has been recorded in centuries-old Chinese lore and Buddhist practice. During a symposium press briefing, this enigmatic virtue caused a perplexed radio reporter to sputter, “But how can one beverage cause the brain to react in both ways?”
The reporter was responding to a finding presented by John Foxe, Ph.D., professor of neuroscience, biology and psychology at City College of New York. It took the modern invention of the MRI machine to map tea’s effect on the complex workings of the human brain. Foxe and his team used electrophysiological measures to monitor brain activity after individuals drank solutions containing 250 milligrams of the amino acid theanine. Theanine is present almost exclusively in the tea plant.
After a person consumes tea, theanine is absorbed by the small intestine and crosses the blood-brain barrier, where it affects neurotransmitters and increases alpha brainwave activity. This alpha brain rhythm is known to induce a calmer, yet more alert, state of mind. “Our results showed that after having theanine, individuals showed significant improvement in tests for attention and activity in cortical regions responsible for attention functions was enhanced,” said Foxe.
EGCG—TEA’S POWERFUL COMPONENT
The big news that came out of the last symposium, held in 2003, was green tea’s possible effect on cancer cells. The buzz word since then has been EGCG, tea’s principle catechin and a strong antioxidant. Researchers worldwide are now looking at EGCG’s effect on overall human health. More than 1,000 professional papers dealing with tea and health were published in 2006.
One of the promising new areas of study is tea’s—and consequently EGCG’s—effect on Parkinson’s and Alzheimer’s diseases. Dr. Silvia Mandel of the Eve Topf Center for Neurodegenerative Diseases in Haifa, Israel, has been studying the effects of EGCG on the neurological health of animal models. Her team found that green tea EGCG appeared to prevent brain cells from dying. EGCG treatment also showed improvements in reducing compounds that lead to lesions in the brains of animals with Alzheimer’s disease. According to Dr. Mandel, “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.” It’s worth noting that the Michael J. Fox Foundation is funding a current study on tea’s effects on Parkinson’s disease.
Tea, red wine, cocoa and many fruits and vegetables are rich in flavonoids, a type of antioxidant. Adding flavonoids to the diet shows positive effects on chronic diseases, including cardiovascular disease and certain cancers.
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 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 milligrams of flavonoids per day, while non-tea drinkers averaged about 33 milligrams. A cup of tea contains approximately 125 milligrams of flavonoids.
A diet rich in flavonoids could improve blood vessel function. New research presented by Claudio Ferri, M.D., professor of internal medicine at the University of L’Aquila in Italy, provided additional insight into how tea flavonoids provide support for cardiovascular health. “Our studies have found that tea flavonoids brought about a decrease in arterial stiffness, suggesting that tea consumption may have favorable effects on cardiovascular disease,” he reported. His studies also showed tea’s positive effects on reducing blood cholesterol levels and providing dilation of blood vessels to help manage blood pressure.
TEA AND WEIGHT MANAGEMENT
With more than two-thirds of the U.S. adult population overweight or obese, scientists are looking for medically sound ways to help consumers manage their weight. Eva Kovacs, Ph.D., clinical research manager at Unilever North America, reviewed the existing scientific literature on green tea, weight loss and metabolism. Kovacs looked at several research studies conducted in recent years that suggest that green teas may aid in weight management by reducing body fat, and in particular, visceral fat. “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 Kovacs.
Consumers worldwide are being offered a host of ready-to-drink teas that tout tea’s ability to reduce weight and speed metabolism. Kovacs warned that green tea products are no magic bullet for weight loss and should only be included as part of an overall diet-and-exercise strategy to achieve a healthy body weight.
The U.S. Department of Agriculture is spending significant time and money studying America’s soaring incidence of diabetes. Its preliminary research has looked to tea as a possible solution because individuals with diabetes have increased levels of oxidative stress. Because tea is high in antioxidants, tea or tea compounds may have an independent effect on insulin signaling and glucose metabolism. David Baer, USDA research physiologist, reported that preliminary studies point to tea consumption and a reduced risk of type 2 diabetes.
THE TEA INDUSTRY’S ROLE
One of the leading spokespeople for tea’s role in a healthy lifestyle has been Jeffrey Blumberg, professor of nutrition science and policy at Tufts University. Blumberg was one of the moderators for the 2007 symposium. He likes to point out that it’s not surprising that the health benefits of drinking tea have led to a robust body of literature that is very promising. Plants are known to have potent bioactive compounds, which is why diets rich in plant-based foods are known to support the body’s fight against many chronic conditions associated with aging and disease. Research continues to show that tea contains bioactive compounds that have roles within human cells. “The data presented at this year’s symposium extends the apparent benefits of tea beyond reducing the risk for cardiovascular disease and cancer to new facets of health,” said Blumberg. He went on to warn tea professionals that it is premature to label their products with health claims that may or may not be proven in further clinical trials. “You should wait until all the evidence is in before marketing tea as anything more than a healthy beverage.”
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