JAMA:  Coffee and Tea Intake, Dementia Risk, and Cognitive Function

Findings In this prospective cohort study of 131 821 individuals from 2 cohorts with up to 43 years of follow-up, 11 033 dementia cases were documented. Higher caffeinated coffee intake was significantly associated with lower risk of dementia. Decaffeinated coffee intake was not significantly associated with dementia risk.

Drinking 2 or 3 cups of coffee resulted in half as many people getting dementia.  You can read the entire study, or stop being a pussy and have a cuppa joe.