Green Tea; Theanine, Caffeine, and GABA

Among its many health benefits for people with Barrett's esophagus, green tea also seems to reduce reflux by tightening the lower esophageal sphincter. Green tea's effect on reflux is caused by the caffeine and theanine in it, both of which affect the CNS control of the LES. Caffeine decreases the amount of GABA in the Vagus nerve while theanine increases the amount. More GABA in the Vagus nerve produces a tighter LES, and a tighter LES produces less reflux. Since the theanine in green tea has a more potent effect on GABA than caffeine, green tea should, in general, reduce reflux. Indeed, it does just that for me.

Since caffeine undoes some of theanine's good deeds, it might be nice, especially at night, to brew a cup of high-theanine, low-caffeine tea. I know that most of the caffeine is released from tea leaves in the first 30 seconds or so, but I can't find reliable information on the release of theanine from tea leaves. Decaffeinated green tea may offer a solution as it seems that supercritical CO2 decaffeination (a method used for all organic decaf green teas), leaves in most of the theanine. Also, I believe there's more theanine in high quality loose leaf tea than in teabag tea, so I would generally recommend loose leaf teas.

A post on theanine supplements coming soon....