Many tea discussions have revolved around the topic of caffeine. Myths have been busted around the idea of the 30 second steep to lower caffeine in the cup. Research has been launched around the effect of steep time and temperature on extraction. The folks at Camellia Sinensis in Montreal have been looking at caffeine content in particular tea plants. And now Popular Science presents information about the interplay between caffeine and some other stimulants in tea.
The Center for Disease Control and Prevention reports that four times as many people get their regular caffeine dose from coffee as from tea. But does the source of the caffeine make a difference?
Caffeine may be the most powerful stimulant in tea and coffee, but it isn’t the only one, and it doesn’t act alone. The amino acid theanine is present in tea. A 2008 study by nutritional psychologist Crystal Haskell-Ramsay of Northumbria University, England, found that taken together in large doses, there was a synergistic effect between caffeine and theanine. In combination, the substances made subjects more alert than when taken alone, improving reaction time and memory. But there was a catch. When taken in small doses, such as found in tea, the theanine actually reduced the effects of caffeine.
Haskell-Ramsay followed in July of this year with a published study with co-researchers Dodd, Kennedy, and Riby, in Psychopharmacology looking at how caffeine and theanine combinations may affect cerebral blood flow.
Several other studies have been published about the connections between caffeine and theanine, including papers in The Journal of Nutrition and the Journal of Nutrition Neuroscience.