My personal take is that body and soul are different parts of our organism, along with a third part, spirit. I think without healthy relationship of all three of these parts our body will wither/become ill. That's not to say that there aren't factors outside of soul and spirit that can cause harm to the body, but all three must be healthily nurtured for each to be free from dis-ease. "Body" is the part I can touch and feel: blood and bone. "Soul" is that indescribable "thing that is uniquely me" and yet also can connect so easily at the level of collective unconscious with that which is uniquely you. "Spirit" is that part of my being that brings the soul and the body together, it is my inspiration, my get-up-and-go, the spark that light the fire that illuminates my soul. When the 3 are united and working harmoniously together it is fairly easy to live in this human state that we like to call "happy". On a higher level, when the three become one, we may achieve nirvana.