Tart cherries contain melatonin, a hormone that helps make you feel sleepy. Two tablespoons of tart cherry juice has been shown in studies to be just as effective as a melatonin supplement. So, pour yourself a little cherry juice nightcap for a tasty bedtime sleep aid. Cherries and blood pressure. Cherries are an excellent source of potassium, which helps to lower blood pressure by getting rid of the excess sodium in our body. Eating cherries helps keep potassium and sodium in balance, and can prevent hypertension from occurring.