Although it looks similar to sweet potato, yam and sweet potato are not related at all. Featuring a cylindrical shape with blackish or brown, bark-like skin and white, purple or reddish flesh, yams are starchier and drier than sweet potatoes. While there are over 600 species of yam available all over the world, only a few of them are considered edible. Yam can be cooked, fried, boiled, roasted or pounded before eating. Yam should not be eaten raw due to its acrid nature – the tubers contain toxic substances that can irritate and inflame the throat and buccal cavity if consumed raw. It is a rich source of carbohydrate, dietary fiber, vitamin C and B6.