There are around 600 varieties of Yam available in the world. Each variety has its own taste, color and properties. Barbados Yam, Chinese Yam, Yellow Yam, White Yam, Hack Yam, Sweet Yam, Mozzella Yam are a few varieties. There are difference between north Indian and south Indian Yam. In North, Yam will be violet in color, whereas in the south it is the mixed yellow and white. Since each place, having the unique shape, color and taste, it is difficult to find the origin of Yam.

Even though, the researchers saying that the Yam is being used from B.C. 5000 in Western Africa. The Yam is derived from the West Africa word "Nyami". The meaning of the word is "Eatable". Later this word is converted to "inhame" by Portuguese or Spanish. Later the English word "Yam" is introduced.

95% of Yam is produced from Western Africa. Even today, the Yam is being used as basic food by some people in Nigeria. The Europeans were spread this Yam into various places. While getting slaves from Africa, they took this Yam also along with them as the basic food for them.

When compared to other tubers, yam has lots of fibers. It will cure constipation and bile. Since it has complex carbohydrate, it will mix with blood slowly. So sugar patient also can consume this food.