From the Tea and Health Symposium from September 2007: Dr. John Foxe, Ph.D., Professor of Neuroscience, Biology and Psychology at City College of the City University of New York, has been conducting human studies to measure the effect of theanine, an amino acid present in all kinds of tea (not herbal), on the brain and attention. Theanine can cross the blood-brain barrier and has been shown to reduce mental and physical stress. Dr. Foxe monitored brain activity in subjects after drinking either 250 mg of theanine or a placebo. The subjects then worked on various attention-related computerized tasks. “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,” he said. His research also suggests that theanine in combination with caffeine may be more effective than either one alone in improving attention. Blood concentrations of theanine increase and the brain’s alpha waves are affected just 20 minutes after consuming theanine. Alpha waves are associated with a calmer, yet more alert, state of mind. This effect lasts about 3-4 hours, and Dr. Foxe speculates that may be why people tend to have a cup of tea every 3-4 hours during the day.
(Please keep in mind that these findings do not necessarily mean that all or any particular tea will confer these benefits to the consumer. Tea research is in its infancy and caution should be used when drawing conclusions about the actual health benefits of any tea product. The Tea Table, LLC does not claim that tea has recognized health benefits.)