Purple Yam - Consisting of flesh both purpleand dark purple in color, the purple yam contains not only all the nutrients ofthe regular yam, but also a significant amount of selenium elements andanthocyanin. Anthocyanin plays an effective role in the prevention andtreatment of over 100 types of diseases. It has been labeled as one of theseven most necessary nutrients for good health. Selenium is also an imperativeelement in the reduction of fatigue, aging and enrichment of blood for thehuman body; it is touted as the king of cancer cures.