The Campbells, father and son, call it the most important health breakthrough of all time. But it’s no magic bullet or amazing new technology. And yet the science is crystal clear: Whole fruits, vegetables, nuts, beans and grains have healing powers and serve as the world’s best medicine. That’s the message of a new documentary movie, “PlantPure Nation”. The movie tells the story of noted nutrition scientist T. Colin Campbell and his son Nelson who…