Grown in the United States, Runner peanut varieties are popular because their plants produce consistently high yields. Plus, they are more frequently used for peanut butter. As a matter of fact, peanuts are an especially good source of healthful fats, protein, and fiber. They also contain plenty of potassium, phosphorous, magnesium, and B vitamins. Fiber, for instance, improves blood cholesterol levels and lowers the risk of heart disease, stroke, obesity, and type 2 diabetes