As people sit down to enjoy July 4th cookouts this weekend, they're sure to find a slice of watermelon on their dinner plates. Watermelon is the perfect summer fruit -- sweet, juicy, and refreshing. Not only is watermelon a great hot weather taste, however, it's also amazingly good for you.

Among its many phytonutrients, naturally occurring compounds that interact with the body to improve health, is one called citrulline. Researchers are just getting to know this particular nutrient, but what they've discovered is that it can give your body a boost, in more way than one.

Citrulline increases nitric oxide levels in the body, which opens up the blood vessels, just like Viagra, they say. Though researchers also say that citrulline isn't "organ specific" like Viagra, it does increase circulation body-wide. Seems like a good enough reason to try a slice, doesn't it?