Why do dogs eat grass? According to behavioral experts, it could be for one of many reasons: to induce vomiting because of upset stomachs on the theory the grass tickles the throat and stomach lining; to get attention, because they know you don’t want them to eat grass; their processed diets are nutrient deficient; their diet lacks enough fiber; or maybe because it tastes good since we can’t ask them why we get to make up the reasons!
According to experts, the nutritional value of grass is contingent on digestibility. The more digestible, the higher the crude protein value. However, this applies to rudiment animals, such as cows and sheep, who have highly unique digestive systems, i.e., they have four stomachs to process grass. The nutritional value of these native grasses varies significantly. Razz (my dog) prefers one particular field in the woods, for which I am grateful since the risk of pesticide application is nil.
This leads to the age-old question of whether dogs are omnivores or carnivores. Looking at pet food trends today, the two camps are well represented. The addition of antioxidants to a cat (the ultimate carnivore), and dog food and treats is rampant. Why antioxidants? Well, according to a 2006 study published in Comparative Biochemistry and Physiology, because blueberries contain phenolics that reduce free radicals, they may reduce exercise-induced oxidative damage (2006;143(4):429-34). The study compared antioxidant levels in sled dogs that supplemented with blueberries within 48 hours post-exercise. The researchers concluded while “the exercise protocol did not cause significant muscle damage as reflected in plasma creatine kinase and isoprostane levels, blueberry supplementation did elicit significantly elevated antioxidant status in sled dogs post-exercise. This suggests that dogs fed blueberries while exercising as compared to dogs fed a control diet while exercising may be better protected against oxidative damage.”
The most popular food additives and supplements in the antioxidant category include vitamins A, C, and E; mixed carotenoids; alpha-lipoic acid (ALA); turmeric; green tea; and mushrooms. Some of these are “nutrients” by definition; herbs are considered unapproved drugs (supplements). Does their intended use dictate appropriate labeling for these ingredients, including as a nutrient? It’s food. Are they added to support the structure-function claim? It’s a supplement.
The actual foods associated with antioxidants seem to be of little interest to my dogs. No blueberry, frozen or fresh, will be consumed in its whole form. Only lightly season cooked orange and green vegetables off my plate are of any remote interest. Salads might be destroyed if dressed with a bit of olive oil. The exception to this rule would be the treats I purchase that include these particular foods. They are a huge hit, though I wonder at times if it’s about the word “treat,” much like their response to the word “go.” So, while wild canines have been observed grazing on berries and herbs of their choice, the closest we get to that in my house would be grass.
I have been taught that if you, the family human, were to walk into a grocery store, and pick up and hold the fruits and veggies you are attracted to, your body will let you know what it’s hungry for. Dr. James Duke, an internationally renowned ethnobotanist, encourages visitors to his amazing herb garden to sample what they are attracted to since it is what their body wants. If you believe, as I do, that the body is intelligent in this regard, perhaps it’s not so far fetched to think dogs crave grass for a myriad of reasons. Maybe this means the reason all the neighborhood dogs eat from the same mud holes in the spring is that they have found a rich source of minerals we pet parents fail to provide them. And while I will confess to discussing this potentially mineral-rich mud with formulators, I still think many questions remain on the dietary choices of our four-leggeds. What scientific rationale could there possibly be for the attraction to poop!?!