We don't know from this study whether diet is influencing sleep or sleep is influencing food choice, or both. But the evidence is abundant that these two pillars of health -- sleep and diet -- affect each other in a number of ways. We've seen a great deal of research that diet and weight control are strongly influenced by sleep, and that too little sleep can make eating healthfully more challenging.

Lay writings about soursop as a sleep aid are easy to find. In the West Indies, soursop leaves are commonly used as a sedative. In the Netherlands Antilles, the leaves are brewed to make a beverage that enhances sleep. The leaves can also be put into one's pillowcase to enhance sleep.

Here's the flipside to the story about foods that can help you sleep better: Eating a diet heavily composed of the "wrong" foods can interfere with your sleep.