Researchers from Mass General Brigham tracked more than 130,000 people for over four decades and found that those who regularly consumed moderate amounts of caffeinated coffee or tea had an 18 percent lower risk of developing dementia compared to those who rarely touched the stuff. //

the apparent benefits weren't tied to heroic levels of caffeine intake, just to steady, mid-range consumption – roughly two to three cups a day – suggesting that consistency matters more than turning yourself into a walking coffee bean. //

The researchers are careful to point out that the findings are observational, meaning that they can spot patterns but can't prove cause and effect. //

Even so, the sheer length of the study – 43 years – gives it a bit more weight than the usual "scientists watched 12 undergrads for a fortnight" variety. Tracking habits over that kind of timespan is no small feat, and it offers a rare glimpse into how everyday behaviors play out over the long haul.