From my grandparent to me, there has always been German Shepherds in our family. Starting the 80's all of our dogs started dying much earlier, ~6-7 of cancer. In the early 2000's, we switched to raw diet from premium store bought kibble to raw. Sure enough, not only did their coat improve not a single cancer death under age of 13. I know it's anecdotal, but in my dog world circle and family, we've all observed similar results.
It's a cruel that our best friends and most loyal companions live such short lives as it is. Giving them top nutrition is a small price for the added years.
As to how this applies to humans? If you want to live a long and healthy life: avoid processed foods.