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 POTATOTHE SECRET TO LIVING UNTIL 100A QUICK GUIDE IN STRETCHINGFELXIBILITY AND MUSCLE TONECHROMOTHERAPYCOLOURS AND WELL-BEINGHAPPINESS GUIDEHOW TO BOOST YOUR SEROTONIN LEVEL