From the brain cancer study:

“Findings from this study suggested that higher consumption of coffee may contribute to the lower development of brain cancer in Asian populations. Tea consumption had an inverse association for the risk of brain cancer in American populations, instead of other populations.”

That’s a pretty important footnote that might mean the causal factor here in this study is not coffee or tea, but other foods in the diet. It’s certainly a good reason to pause and question whether to dive into an 8 cups/day routine.