Developed in Spain, in the late 18th century, "Spanish" peanuts are one of the four most popular types of peanuts grown for commercial use today. These peanuts have smaller kernels covered with a reddish-brown skin. Besides, they are used predominantly in peanut candies, with significant quantities used for snack nuts and peanut butter. However, peanuts are also a good source of protein, which is essential for building and repairing body cells. On a side note, most abundant proteins in peanuts can be severely allergenic to some people, causing life-threatening reactions. So, if you’re one of these people, then peanuts are clearly not for you.