The late writer Christopher Hitchens wrote that when you come to New York, you go to bed an hour later and wake up an hour earlier, and I can confirm this anecdotally myself. Noradrenaline is the key 'wake-up' drug of the brain and it may be that the shear repeated novelty and stimulus of this great city is chemically flooding my brain with this brain-protecting substance.
We've all heard the idiom about 'brain food', but could green tea represent a 'brain drink'? Of course, in the rush of enthusiasm about research such as this, we won't slip on the classic banana skin and start extrapolating wildly about the miracle benefits of green tea for brain health simply based on cell culture.
The connection appears to be strong. People with type 2 diabetes are much more likely to develop Alzheimer's disease than their healthy counterparts (up to 65% [2]). In fact, the association also appears to be strong linking the metabolic syndrome, essentially a pre-diabetic state, and Alzheimer's disease [3].