Caffeine might be good for more than keeping you alert.
Researchers in Japan found that while drinking at least one cup of coffee a day lowered stroke risk by 20% and drinking two cups of green tea a day lowered it by 14%, the benefit from both was likely greater than either one on its own.
The drinks work in different ways: An antioxidant in green tea, catechin, has anti-clotting effects. Chlorogenic acid in coffee may lower your chance of developing type 2 diabetes, a risk factor for stroke. Aim for a cup of joe and two cups of green tea a day.