A documentary has claimed purple sweet potato can help you live until 100. Professor Craig Wilcox has been studying the Okinawan diet for the last decade and believes a key factor in their vigorous health can be attributed to the vegetable. Sweet potatoes have been a go to food for the Okinawans for a long time," revealed the professor. "They are easy to grow and they are very economical to producer and they are powerhouses of nutrition." THE ART OF HAPPINESS SERIES PURPLE YAM & PURPLE SWEET POTATO THE SECRET TO LIVING UNTIL 100 A QUICK GUIDE IN STRETCHING FELXIBILITY AND MUSCLE TONE CHROMOTHERAPY COLOURS AND WELL-BEING HAPPINESS GUIDE HOW TO BOOST YOUR SEROTONIN LEVEL