ace 1224 wrote: "With this much speed and power, the blades in these powerful machines hit your spinach, kale, bananas, almonds and everything else with a powerful force that their cell walls literally explode, instantly releasing all the dense nutrients and flavors trapped inside. That would be hard for your stomach to do even if it wasn't already compromised by a lifetime of cooked, processed foods! However, this only happens with a high-end, powerful blender. If you make a green smoothie in an ordinary kitchen blender it may mix up the ingredients somewhat, but the effect won’t be the same. Instead, you’ll waste a lot of energy chewing the lumps and digesting what should be smooth and effortless to absorb."
In Mary Roach's excellent book, Gulp, she discussed the 19th century experiments of William Beaumont who inserted food into a fistula in a patient's stomach in order to observe the digestive process. It is my understanding that he essentially proved digestion is a chemical process--not a mechanical one--which leads me to wonder if a blender is required to break down cellular walls.
Roach also discusses an archaic theory on intense mastication (Horace Fletcher).
I am not a medical person or a biologist. Maybe someone else can chime in on this.