"Following acute ingestion of green tea by six human subjects, HPLC-MS2 analysis revealed that flavan-3-ol methyl, glucuronide and sulfate metabolites appeared in the bloodstream but did not pass through the blood-cerebrospinal fluid barrier. These observations emphasize the discrepancies between in vitro and in vivo evidence on the neuroprotective role of these compounds. If, as has been proposed, green tea exerts neuroprotective effects, this finding indicates that the active components are not flavan-3-ols or their metabolites. Alternatively, a systemic action may be hypothesised whereby dietary flavan-3-ols up-regulate antioxidant defences and/or reduce inflammation, the benefit of which may be effective throughout the body."
http://www.ncbi.nlm....pubmed/16910171
Which should make about a zillion or so brain cell studies looking at EGCG and brain disease irrelevant for humans. EGCG passes the blood-brain barrier in rats but according to this not in humans. So another zillion animal studies looking at EGCG and brain disease may very will be irrelevant for humans. Strange that this study from 2006 has not received more attention.
Edited by Blue, 24 August 2009 - 10:12 PM.