henry copeland:

Habitual tea drinking modulates brain efficiency: Evidence from brain connectivity evaluation -- ScienceDaily

Although individual constituents of tea have been related to the roles of maintaining cognitive abilities and preventing cognitive decline, a study with behavioural and neurophysiological measures showed that there was a degraded effect or no effect when a constituent was administered alone and a significant effect was observed only when constituents were combined. The superior effect of the constituent combination was also demonstrated in a comparative experiment that suggested that tea itself should be administered instead of tea extracts; a review of tea effects on the prevention of Alzheimers disease, found that the neuroprotective role of herbal tea was apparent in eight out of nine studies.
- www.sciencedaily.com