First, I would like to apologize to every single person to whom I every suggested that a few veggies in dog food could be healthy.
While not wrong, per se, it was the thin edge of the wedge. Back in the early 2000s, which seems like a millennia ago, there was a trend of making the veggies the 1990s popularized visible. Little bits of “fresh” peas and carrots, mostly. Cheap and easy to source, they did also provide a few vitamins and minerals that otherwise might need to be supplemented.
Now they’re everywhere. And not just little bits. It is now incredibly difficult to find a dog or cat food that doesn’t have a significant amount of peas, pea protein, or pea fiber added; and those that don’t simply use lentils or chickpeas instead. While dogs, unlike cats, are not obligate carnivores and some can be healthy on a veggie or even vegan diet, it is not ideal. As grain-free high-protein diets have become popular, we’re seeing more and more legumes used as protein sources. In the past few years, these diets have been increasingly linked to a risk for cardiomyopathy. This may be due to a problem we “solved” in the 1980’s: the critical role of the amino acid taurine. Unfortunately for dogs, they weren’t included in this solution; the role of taurine in feline diets is well recognized, but dogs have some ability to synthesize taurine from cystine (another amino acid), and so there are no requirements for taurine in dog food.
Unfortunately, not only are peas and other legumes low in taurine, but other newly popular ingredients like rice bran and beet pulp interfere with cystine absorption– therefor reducing the ability of dogs to synthesize taurine. Many grain free diets also contain “novel proteins,” which have also been linked to cardiomyopathy risk; however, many, such as lamb and even ostrich had a long use history and weren’t truly novel. They do have low cystine levels, though!
Research is ongoing. I’ll definitely be keeping an eye on the findings, I would encourage anyone with dogs to do the same– especially at risk breeds like dobermans and all retrievers. In the meantime, I’m choosing to limit legume based foods and treats, and Flora gets plenty of high-taurine organ meat treats during training. I don’t think she minds.