By Alan Bjerga
Sept. 18 (Bloomberg) -- Tea may improve the ability to concentrate because of a substance found almost exclusively in several types of the beverage, according to research presented at a conference highlighting ties between tea and good health.
Theanine, an amino acid present in black, green and oolong teas, actively alters the attention networks of the brain to improve both calmness and alertness, according to John Foxe, a neuroscience professor at City College of the City University of New York.
``The only way you or I are going to get ahold of theanine is through a good cup of tea,'' Foxe said today at the conference at the U.S. Department of Agriculture in Washington. His research was sponsored by Unilever, which includes Lipton Tea among its more than 400 brands.
Claims of health benefits have helped tea sales in the U.S. surge, to $6.5 billion last year from $1.84 billion in 1990, according to the Tea Association of the USA. Beyond helping alertness, tea can also ease the symptoms of Alzheimer's disease and reduce cholesterol, scientists said.
Foxe said that in human trials, theanine has been shown to affect the brain's alpha waves within 20 minutes, and that the calming effects and state of heightened alertness can last three to four hours.
High Doses
The doses given to test subjects were about 10 times what a person would get in a normal cup of tea, said Foxe. He now plans to lower the amount of theanine administered to see its effects at lower levels.
Improved alertness is one of several benefits tea companies and scientists are touting for the beverage, which Americans consume at the rate of 2.25 billion gallons a year, or 4 percent of world consumption. That's far behind global leaders India and China, which together drink about 40 percent, according to the Tea Industry Forum in Kingston, Australia.
Researchers have also linked tea to better heart health and immune function and reduced risk of some forms of cancer.
Sylvia Mandel, a scientist at the Eve Topf Center for Neurodegenerative Diseases in Israel, said her research suggests the equivalent of two to four cups of green tea a day may keep brain cells from dying in animals induced with Parkinson's disease. The next step is to see if the results can be replicated in humans, said Mandel, whose research was funded by her center.
Today's conference was sponsored by the American Cancer Society, the American College of Nutrition and the New York- based Tea Association, which includes Peet's Coffee & Tea Inc. and Tazo Tea, a unit of Starbucks Corp.
留言列表
