Tea also contains L-theanine which modulates the effects of caffeine: http://www.ncbi.nlm.nih.gov/pubmed/10737183
Re:What caffeine does to your brain
by provemewrong on Monday July 20, 2015 @05:28AM
(#9914874)
True, but in miniscule amounts. Significantly lower than the doses taken by the people who use L-theanine as a supplement. Also L-theanine to caffeine ratio is all wrong.
>Why pick pure l-theanine and caffeine over green or black tea?
>Most studies done on the l-theanine-caffeine combination have a l-theanine to caffeine ratio that isn't consistent with ratios you would expect from most teas. The studies used about twice as much l-theanine as caffeine by weight. The ratio found in most teas is reversed, with the possible exception of high quality green tea. [1]
Which is why I drink high quality green tea.
Why coffee specifically? Other things contain caffeine. Tea, for example.