Eating foods rich in flavanols, like dark chocolate or berries, might help older people remember details better by boosting a specific part of the brain that separates similar memories—but it doesn’t help them remember things after a delay, which uses a different brain area.

If you're between 50 and 69 and eat a daily dose of cocoa flavanols for three months, you might get better at remembering small differences between similar things—and your brain’s memory area might get more blood flow, helping fight off some of the memory slowdown that comes with aging.