Even though yams, of which there are about 200 varieties, are one of the most popular and widely consumed foods in the world, they are not readily available in most stores in the United States. There is much confusion between yams and sweet potatoes in the U.S., as most vegetables advertised as "yams" are really orange-colored sweet potatoes. True yams in the U.S. are usually found in Asian and African food markets. They are a staple in the diets of many different countries, such as South America, Africa, the Pacific Islands, and the West Indies.
Yams, whose flesh colors vary from white to ivory to yellow to purple while their thick skin comes in white, pink or brownish-black, are a good source of dietary fiber, potassium, vitamin C, manganese and vitamin B