Found out that it takes at least an hour and a half for EGCG to be absorbed and to reach the brain in sufficient quantity. Hmm...
What about the two other compounds in tea that may have an effect on the brain, namely caffeine and L-theanine*? Caffeine gets into the brain very quickly—within 30 minutes—and seems to leave pretty quickly too. By contrast, L-theanine takes its time—it reaches its peak after an hour, and levels dwindle more slowly.
David Camfield and his colleagues think that this difference in timing may explain why experiments using caffeine and L-theanine have yielded mixed results when it comes to mood and cognitive (= thinking) performance. They did a meta-analysis of a large number of published studies of the effects of caffeine and L-theanine together and came to the conclusion that the effects were mild to moderate at best.**
However, all of these studies involved a single dose of the compounds given together at a single time point. This is not at all how we drink tea!
Instead, we usually sip tea over a rather long period of time—time enough to build up L-theanine levels and even EGCG levels, while keeping caffeine levels up all along. It's as if your brain were given all the compounds simultaneously in a continuous infusion.
You may even have noticed a time sequence when you sip your tea, first arousal from the caffeine, and then, when the L-theanine kicks in along with the caffeine, an ability to focus, followed by a sense of calm coming from the EGCG.
Is that what you have experienced?
* L-theanine is a non-protein amino acid found almost exclusively in tea.
** Camfield, David A; Stough, Con; Farrimond, Jonathon; Scholey, Andrew B. Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis. Nutrition Reviews, ISSN 0029-6643, 08/2014, Volume 72, Issue 8, pp. 507 - 522
No comments:
Post a Comment