Turns out that coffee's good for more than jump-starting our mornings or keeping us awake during meetings. A lot of recent research suggests that coffee offers a host of potential health benefits.Every day, Americans drink 400 million cups of this incredibly complex beverage, which contains more than 1,000 compounds that can affect the body. The most commonly studied are caffeine (a nervous-system stimulant that's known to have positive cognitive effects) and polyphenols (antioxidants that can help…