"The take home is that regular use of caffeine produces no benefit to alertness, energy, or function. Regular caffeine users are simply staving off caffeine withdrawal with every dose – using caffeine just to return them to their baseline. "
https://youarenotsosmart.com/2010/02/22/coffee/
I've read this years ago, forgot most of it and became a coffee addict again.
@koos I have read though that caffeine is neuroprotective and moderate regular users of caffeine experience onset and progression of neurodegenerative diseases of age more slowly.
@Tezcatlipoca thanks for checking! Be careful though: "This is an observational study, so no firm conclusions can be drawn about cause and effect[...]"
Also: "results of previous studies looking at this issue have been inconsistent"
I'm particularly sceptical regarding the relatively small size of the study. Out of not even 2k people, how many drink nearly a liter coffee per day?!
The study I found only had old Italians in it.
@koos Meta study on caffeine safety came out a couple days ago. Makes some really straightfoward recommendations on how much is safe: "400 mg/day for adults, 300 mg/day for pregnant women, and 2.5 mg/kg/day for children and adolescents" http://www.sciencedirect.com/science/article/pii/S0278691517301709
Of importance maybe that that is less than the 600mg/day from the other study. But also tantalizingly not that far away. 400mg is like 4 cups.
@koos True, good points. I am definitely not going to be throwing 6 cups back a day to try to stave off Parkinson's especially without considering how it affects everything else. But it is a pretty decent sample from two populations. I wouldn't be surprised if in the end they find some mechanism through which caffeine (or something else in coffee even) is truly neuroprotective. I remember there being more research than our quick searches found.