Green beans are one of the few beans that are eaten fresh. Though low in calories, green beans are packed with nutrients, especially vitamins C, K, and A. They are also a good source of iron and fiber. Mild in flavor, green beans can be prepared in a variety of different ways and are a classic ingredient in salad Nicoise and green bean casserole. They are easily grown in a backyard garden can be stored in the refrigerator for up to one week.