While plants and micro organism have the capability to produce the vitamins necessary for the metabolism themselves, humans and animals have unfortunately lost this ability during evolution.
One of our discoveries many years ago is the danger of oxidation. When the fats inherent in all ingredients are exposed to oxygen, heat, light, and time, they begin to oxidize.
Since the advent of food processing, much debate has ensued as to which food is best. There are extruded, pelleted, baked, canned, semi-moist, life-stage designed, high protein, low protein, "natural," fortified, anti-allergenic, and disease treatment formulas.
The importance of raw, natural, fresh foods in the diet is self-evident. It is the form of food all creatures on planet Earth are genetically adapted to.