Once you begin your search to improve your dog's health you're often struck with the question of supplementing them with the individual nutrients that you feel will benefit them most, based on where their weaknesses lie or adding nutrient dense whole foods that contain those same nutrients along with others. At CPN we believe you must add both types. Some times it's just not feasible to try and fortify a nutritional product with a whole food ingredient that may in turn deliver too much of other nutrients involved. That's when we must look at individual nutrients like tocopherols, antioxidants, omega 3's, some amino acids and phytonutrients. Egg is and always has been the gold standard for delivering a nearly perfect protein panel while also supplying dozens of other nutritional benefits and that is why you will find it listed as the main ingredient along with several other whole food ingredients in both Vertex and Structure. To rely on synthetic nutrients for any more than a very small percentage of the overall nutrient value is in our opinion an exercise in futility. Animals recognize natural patterns of nutrients. Synthetic nutrients are not natural. They are never found by themselves in nature. Taking these isolated nutrients, especially at the ultra-high doses found in formulas today, is more like taking a drug. There are studies that actually show the body treating these isolated and synthetic nutrients like xenobiotics (foreign substances). For an isolated nutrient to work properly in the body, it needs all the other parts that are naturally present in the food too. When they are not present with the nutrient being consumed the body must get them from stores in the body. Once those stores are used up the isolated nutrients doesn't work as well any more. Long story short: Read the label of what ever it is you're thinking about feeding your dog. Look for nutrient dense whole food ingredients. Beware of pills. They may work for a short period but for not for the long haul.